CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => Speakers => Topic started by: Marvey on March 02, 2013, 05:44:57 AM
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Madisound BK-16 Fostex fe166 kit.
Getting back to speakers. This is going to be a test mule for exploring backloaded horns and the EC Leviathan or 2A3.
Photo of current system / setup (http://www.changstar.com/index.php/topic,833.msg21242.html#msg21242)
Discussion of active crossovers (http://www.changstar.com/index.php/topic,833.msg21910.html#msg21910)
Frequency response (http://www.changstar.com/index.php/topic,833.msg21912.html#msg21912)
EQ settings (http://www.changstar.com/index.php?action=dlattach;topic=833.0;attach=3106;image)
Why? (http://www.changstar.com/index.php/topic,833.msg21917.html#msg21917)
System Description (http://www.changstar.com/index.php/topic,833.msg21920.html#msg21920)
Fe166En Nearfield Measurement (http://www.changstar.com/index.php/topic,833.msg28744.html#msg28744) (no smoothing)
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My jaw dropped when I saw those cuts and routing. And then I panned over and saw the Fostex box. ;D Is that from Madisound? Looks like fun!
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good stuff. Speakers are fun
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Tell me how it sounds! that 16 kit looks delicious. It is indeed from madisound.
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I shouldn't even watch this thread... but that does look interesting! :-Z
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The kit is cheep in terms of money. You can slap it together quickly, or take your time. I'm taking my time on this one.
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Progress. Can never have enough clamps. BTW, all these are indoor low light shots with the Fuji.
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Plywood instead of MDF for cost reduction?
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Plywood instead of MDF for cost reduction?
It's birch, costs a bit more than MDF.
Since it's a kit, it makes sense. I use to hate wood chips and having to extensively predrill over and over back in my speaker building days and I had to cut it myself.
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Do you put any fasteners in there or just glue the sh_t out of it?
So much for taking you time with this one ;)
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Plywood instead of MDF for cost reduction?
It's birch, costs a bit more than MDF.
Since it's a kit, it makes sense. I use to hate wood chips and having to extensively predrill over and over back in my speaker building days and I had to cut it myself.
You don't see plywood when u zoom in?
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You don't see plywood when u zoom in?
It's birch plywood. The more expensive, lighter alternative to MDF for box building (also chips more easily when cutting and requires tons of predrilling).
edit: I think this is the specific kit: http://www.madisoundspeakerstore.com/full-range-speaker-kits/fostex-bk-16-folded-horn-kit-pair/
Complete aside: I once used random construction adhesive for box building thinking it would be better than regular old wood glue. I spilled a bunch on my ungloved left hand thinking I could remove it with SOMETHING later. Fast forward an hour and I'm frantically using everything (including gasoline) to get it off. I looked like I had a zombie hand for a couple of weeks there. It wouldn't come off without skin.
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Longish setting wood glue is absolutely necessary. Not fun fitting all the pieces together on top of the the left side panel and then having to fit the right side panel in place.
One speaker is undergoing testing right now. Hard to gauge overall clarity or openness because only using one speaker, but it does sound promising.
- Kiss flat FR good-bye. The horn and driver WILL create a comb effect in the response for the bass and lower mids. It will be interesting to see if surgical EQ can correct this. I am not hopeful.
- I was afraid this would have a slightly rising response like the Voxactiv's. It does not. In fact, I would describe this speaker has having a somewhat reverse TH-900 response. Bass extends surprisingly low to 50-60Hz, but then drops like a rock. Upper mids on up through high treble are recessed. Strong emphasis on low to mid-midrange.
- Rolled off up top. Personally, I WILL need a supertweeter to augment the Fostex. A joke among speaker designers is that these kinds of full range horns are for old people who have lost their high frequency hearing. I think there's some truth to that. As an FYI, old audiophiles hate it when you even hint that their high frequency hearing is shot. They get all testy, defensive, and shit.
- It's very fast sounding. Evident on string plucks, percussion, voices, etc. Very punchy. Throws sound at you. I almost jumped off my seat to the bass Jennifer Warnes' Rock You Gently. Funny considering that only the harmonics of the bass notes were being produced - the fundamental bass notes being well below what this speaker could reproduce.
- Amazingly resolving in the midrange.
- Congested on passages where there was a lot was going on. But this could be because I was using only one speaker, and hence driving it louder than I would if there were two speakers.
- I suspect the solid-state electronics used are holding this speaker back. A well executed tube amp may be the ticket for this speaker to reach its potential in terms of dynamics and resolution.
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So would you call the frequency a reverse V? How would you compare performance to say, a Klipsch RF-42 II, or would that be apples and oranges?
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Hope you could try out the Loki kit as well, been lookin into getting one :D This kit would be something to consider if it weren't for the comb effect, shall look at further impressions.
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The audiophile desktop speakers I built are similar to the Loki kit. Except much smaller woofer driver (but higher quality Seas) and actively powered. I had also built another similar kit to the Loki - again using Seas drivers. The Loki should sound great, but I'm past the point of low efficiency passive crossover 2 ways. Have built over half a dozen or so in my lifetime.
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I know its not fair to compare but are full-range's generally 'faster' than the Seas coax? I would love to go active anytime but I have no expertise on building speakers so hopefully will learn with time.
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Are you dampening the enclosure with felt or wool?
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So would you call the frequency a reverse V? How would you compare performance to say, a Klipsch RF-42 II, or would that be apples and oranges?
Not really comparable. The BK16 kit is a back loaded horn. The klipsch has a front horn tweeter. Different sound and goals.
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Damping with acoustic-stuff fake will. Only a little bit behind the driver.
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I know its not fair to compare but are full-range's generally 'faster' than the Seas coax? I would love to go active anytime but I have no expertise on building speakers so hopefully will learn with time.
I would not categorize the Seas as "fast". Low efficiency designs never are. It's all about compromise. I'll say much more later when I get back home about pluses and minuses. Even active has minuses. The Fostex is almost stat fast. But with much more impact and punch.
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I know its not fair to compare but are full-range's generally 'faster' than the Seas coax? I would love to go active anytime but I have no expertise on building speakers so hopefully will learn with time.
I would not categorize the Seas as "fast". Low efficiency designs never are. It's all about compromise. I'll say much more later when I get back home about pluses and minuses. Even active has minuses. The Fostex is almost stat fast. But with much more impact and punch.
Something about low efficiency designs I've heard (< 90 db/w) don't really lend themselves to low volume listening. Like I've felt the need to turn them up, don't know if it's from lack of resolution or what, but it could be the speed thing.
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Something about low efficiency designs I've heard (< 90 db/w) don't really lend themselves to low volume listening. Like I've felt the need to turn them up, don't know if it's from lack of resolution or what, but it could be the speed thing.
this is so true - actually been toying with buying a fostex kit just for this reason. I love the way my speakers come to life but I hardly listen to them because they sound pretty flat at low volume.
..dB
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You guys talk like it's exclusive to speakers. :)p8
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aaah but it is easier to power headphones with "megawatt" equivalents to overcome this petty deficiency , I know my alternative is to heft that hernia maker up the stairs ( once it is fixed ) and just be done. real watts in speaker land are not cheap
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True, always felt that my current speakers have no dynamics at low volumes. It would be interesting indeed to hear the demerits of active crossovers. I tend to listen pretty loud in the living hall though when no one is around occasionally(80db average for short periods). The only thing in my experience that I can listen at really low volumes and be satisfied with is the HD800 as I have no particularly efficient speakers.
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aaah but it is easier to power headphones with "megawatt" equivalents to overcome this petty deficiency , I know my alternative is to heft that hernia maker up the stairs ( once it is fixed ) and just be done. real watts in speaker land are not cheap
The part about speaker amps is true as well. There is something about arc welding amps.... lose the purity of the sound.
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Some random related thoughts:
- Could rubber speaker surrounds rob the drivers of ability to reproduce soft sounds? I've noted high-efficiency drivers tend to use foam or paper surrounds. Foam or paper surrounds are of course less durable than rubber.
- Is it that the arc-welding amps lose that purity of tone, or is it because arc-welding amps tend to be used with low efficiency (but usually) very accurate speakers with complex crossover networks which rob the sound of its purity. I know we are getting into BS audiophile terms now, but there's really no way of how to put this. I tend to notice that transducers without crossovers have a purer tone. For example, the ER-4S has a certain purity to the sound compared to the UERM, even though the ER-4S is more colored.
- There always seems to be something in the way when there is a passive crossover in the signal path. Passive crossovers (2nd order) consist of at least one sizable capacitor and inductor. There are usually additional caps and inductors for baffle-step correction, and another set of RLC components parallel to the driver for impedance correction. Considering how a SE tube amp maybe has one small interstage cap and one output transformer (and well designed SS amps sometimes have no reactive components) - we seem to be adding a lot of extra shit between the driver and output of a amp.
- The backloaded horn concept is interesting. This Madisound BK-16 kit does not need baffle correction (or any crossover components). Baffle correction is needed for speakers placed away from wall boundaries because higher frequencies bounce off the speaker baffle. The wider the baffle, the lower the frequency where the higher frequencies started to get augmented. In other words, baffle correction circuitry in the speaker lowers efficiency (it essentially is a treble shelf filter to push down the treble past a certain frequency.) The BK-16 takes the backwave (opposite phase signal) and pipes it through a transmission line/horn (tuned for bass and low mids). But the time the sound reaches the mouth of the horn, the signal is in phase with that of the driver. Hence, we are actually making the backwave of the driver contribute quite a lot (rather than have the energy of the backwave be absorbed in the stuffing materials or only partially using the energy of the backwave to augment low bass, as in a ported bass enclosure.)
- The BK-16 kit sounds
good excellent at low volumes. Been staying up a night listening at low volumes (on the first floor - bedrooms are on second floor) and wondering WTF do headphones cost do much and how headphones are such a fricking waste... Don't be surprised if I cancel my Electra order and sell my Jades so I can get a Leviathan.
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I have been very curious about the Fostex BK-16 for quite a while. It is a very decently price kit, and very well regarded. I'm even more curious now. I'm holding back quite a bit for several reasons, but those Fostex BK-16 seem like pure win. Sorry if my questions are too noobish but do these through a narrow sweet spot? paired with a sub (and perhaps super tweeters) would there be any problems in using these for home theater applications (perhaps 4 channel)?
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I have been very curious about the Fostex BK-16 for quite a while. It is a very decently price kit, and very well regarded. I'm even more curious now. I'm holding back quite a bit for several reasons, but those Fostex BK-16 seem like pure win. Sorry if my questions are too noobish but do these through a narrow sweet spot? paired with a sub (and perhaps super tweeters) would there be any problems in using these for home theater applications (perhaps 4 channel)?
The sweet spot was wider than anticipated. I think the single driver concept works well. The qualifier is that polar / power response of the BK-16 kit is horrible. The drivers, because of their size, beam high frequencies. The mouth of the horns play back bass to lower mid frequencies. But think of it as customized EQ. Move your head down for moar bass. Move your head up for less bass. Angle speakers outward for treble roll-off... LOL.
I would highly recommend for home theatre, but not a cinema simulator in your home. These are certainly not high SPL speakers - too much distortion for a 6" trying to carry such a wide-range. I think you would like it more with super tweeters. For me, it's on the edge. I could easily enjoy it without supertweeters; but I'm not that deaf, at least not yet, so I do plan on getting super tweeters. Maybe in 5 more years.
As far as subwoofer integration, the point of the the BK-16 is NOT to cross anything over or put any extraneous crap in the signal path so it maintains its "purity of tone" as much as possible. I would implement a subwoofer REL style:
- Let BK-16 do its thing and play full range without any crossovers in the way.
- Take a second set of outputs from the amp feeding the BK-16, pad those outputs to line-level, and input into a subwoofer x-over / amp. This really helps the sub integrate with the speakers.
- Cross the subwoofer over anywhere from 28-38Hz with a 12db/octave rolloff. With room gain, the sub should go up to 40-50Hz where it should meet up with the speakers
The supertweeter should be added with one cap in series. Some start the rolloff higher than 20kHz. 0.47uF for example.
BTW, for my living room (TV room) I plan on building the BK-16's little brother: http://www.madisoundspeakerstore.com/full-range-speaker-kits/fostex-bk-12m-folded-horn-kit-pair/ (http://www.madisoundspeakerstore.com/full-range-speaker-kits/fostex-bk-12m-folded-horn-kit-pair/)
P.S.
BTW, come on over.
Luis came over this evening and was enamored with its sound. We should get a group buy for discount going.
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If you guys get a group buy going, I'd be interested. Seems like a fun project to try out.
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You do realize this site will be renamed to the California Full Range Speaker Club soon.
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Thank you very much Marv. The BK-12 seems even better for what I have in mind. And thank you very very much for offering an audition, I'll definitively drop by later in the week at your convenience.
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You do realize this site will be renamed to the California Full Range Speaker Club soon.
Going to need a better acronym than that.
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BK-16 kit measurements...
12" from the left driver. In-room. 1/6 octave smoothing (which is very little)
- Comb effects prevalent at 150Hz and 250Hz. There's obviously some bleed in from the horn mouth a about a 0.5 meter below.
- Minor cone breakup modes at 3.7kHz and 5kHz. Not that bad. Certainly not as bad as the resonances we see in headphone measurements.
- Lots of rolloff measuring so close to the cone.
- Generally, the measurement is not as smooth as headphones. All sorts of boundary effects come into play which create oddities all over the replace. Fortunately, we don't hear at 1/6 octave acuity with real music.
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Marv,
So taking a real broad look at that, can one assume it's "mid-centric" sound from these speakers?
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Measurement 2" from the mouth of the horn.
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Marv,
So taking a real broad look at that, can one assume it's "mid-centric" sound from these speakers?
Mid-centric with very slight ringing at the 3.7k and 5k breakup modes is an accurate way to describe it. I didn't catch the ringing at 3.7k, but Luis actually did. It's important to understand that these resonances are nothing like Beyer or Grado. Also, keep in mind this measurement near the driver only partially takes into consideration the contribution from the back loaded horn.
BTW, our (Luis and my) combined efforts using our ears to EQ actually yielded results which matched measurements. Some stuff was too hard to catch with our ears - the comb effects and so forth.
But more in the next few posts...
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Skipping a lot of intermediate measurements... This measurement was taken at what I would consider the prime listening position, about ~5 feet from the back wall and ~11 feet from the speakers.
RTA 1/3 octave. (The above measurements were 1/6 octave using MLS.)
- Note dips of comb effect at 70Hz, 100Hz, 170Hz.
- Note peaks of comb effect at 85Hz, 150Hz, 250Hz.
- Rolloff begins at 50Hz.
- The slight rise at 20Hz is probably room gain. This speakers are in a living room which opens up into the family room and open kitchen.
- Cone breakup resonances can still be seen at 3.7k and 5k.
- Lacks last 1/2 octave or treble air. It probably won't matter to me in 10-15 years.
- There is more mid-bass than the graph indicates. (we gotta use our ears sometimes)
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After EQ using EasyQ in JRiver...
EQ settings were very light. No more than -3db at most spots. Essentially this is how I EQ'd:
- Notched down peaks from comb effect at 150 and 260Hz, -2db and -4db respectively.
- Brought down midrange region centered at 850Hz down -3db
- Notched down driver resonance modes at 3.7k and 5k by -2db abd -3b respectively.
- Bumped up lower treble region centered at 8k by 2db.
Lots of little EQ adjustments, but very small adjustments. I don't believe in applying EQ with high magnitudes. I also tend not to mess with correcting narrow / small dips.
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Again, subjectively, there is more mid-bass than the measurements indicate. I have a very good room and only need to worry about the left wall. The speaker as it is EQ'd right now sounds nothing like a "horn". In fact, it sounds rather like a studio monitor. I may reverse the slight treble EQ bump to so it sounds less like a studio monitor. What I do find interesting is how much this speaker (and practically every other speaker I've built) responds to EQ. Headphones are EQ'able too. But for some reason, headphones always strongly impart their own sonic signature despite EQ. At least they do so much more strongly than speakers (with the drivers I have chosen so far - I tend not to pick Grado'ish or Beyer'ish drivers to work with.)
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I'll try to hit your place today after work if you're available Purrin. I'll bring my hard drive. :)
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Marv, what you're referring to as comb effects is more like the typical LF room response (with peaks indicating the resonance frequencies (unless the mode is poorly excited by the speaker or or the mic is in a node region for that mode hence not seeing it). The dips in between resonance is just because there's nothing else going on (the response is the sum contribution of all modes at the frequency so you get some contribution from to the resonances below and some from those above).
Looking at your graph the roll-off starts below 200Hz (the horn loading gives it the gentler slope I assume?). The driver itself has an Fs around 50Hz I guess? at least, it seems the loaded resonance is there such that the response drops sharply below that.
In any case, it's a good thing you did not try too hard to compensate for this, as I don't presume the full range driver has so much excursion freedom?
Looks like a nicely behaved driver overall though, ;)
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Na, it's not the typical LF room response (at least the portion 100Hz and above). I've done this a many times with other speakers. I'm pretty sure it's the interaction between the mouth of the horn and the driver. The 70Hz dip could be a room thing though. I'm hoping it's not because otherwise it would be difficult to correct.
The driver's Fs is at 50Hz. The driver does not have any excursion - my guess is 1mm (forgot the specs). It wouldn't do high SPL. And at higher SPL, it does not sound so nice either.
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Humm, interesting. If you can give me the dimensions of the horn (some 2D diagram would be awesome, maybe some scan of the assembly brochure?), I can try a simple simulation of the horn, we'll see what it really does vs. a planar baffle (or no baffle at little even though it's a little silly).
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OK, 20 points for whoever can pick out the funny or interesting thing in the photo...
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Speakers driven straight out of the Schiit headphone amp :)
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How does that sound? And what is the power output at that resistance?
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I have no idea what the Mjolnir power output is at the nominal 8 ohms of those Fostex (rises to 60 odd something at 45-50Hz and 32 ohms at 20kHz). The Crest amp seems to provide better bass extension, solidity, and slightly better control. The Mjolnir output has more air (not unexpected giving its 1+ ohm output Z) and clearer with more microdynamics and plankton - it's more involving of a listen.
You guys didn't notice my super high-bandwidth speaker cables?
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Holy Schiit!
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Now I have no excuse not to try a simulation of the horn loading effect!
http://www.madisound.com/pdf/fostexcabs/Fostex%20BK16%20Cabinet.pdf
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There you go, had a little fun simulating these and here's what I got for a start :)p1. Note that these are for bare wall enclosure (what's the thickness of the stuffing you use marv and where is it located about?), no room reflections apart from floor (speaker elevation ~10cm), no speaker cone modes (just a planar surface with free air resonance at about 50Hz), assumed perfectly rigid enclosure.
This is the A-weight SPL at about 1.5m in front and to the side of the speaker (at ~80 cm height), the black curve shows the speaker pretty much unbaffled:
(http://i374.photobucket.com/albums/oo181/acharpen/Fostex_BK16/Fostex_BK16_BareWall_SPL_dBA_zps0c46d1fd.png)
Marv, as you suggested (can't beat DIY guys to figure these things out before the engineers lol), at least some of the resonances in bass/mid-bass region at due to the horn loading, here are some contour plots of SPL at ~80Hz, 140Hz, 235Hz, 315Hz. That could help to decide on favored glasswool placement (note that without glass wool it probably sounds nasty with the horn mouth output as much if not more energy than the cone itself at these frequencies):
(http://i374.photobucket.com/albums/oo181/acharpen/Fostex_BK16/Fostex_BK16_BareWall_ContourPlot_78Hz_zps71295f5c.png)
(http://i374.photobucket.com/albums/oo181/acharpen/Fostex_BK16/Fostex_BK16_BareWall_ContourPlot_140Hz_zps36118384.png)
(http://i374.photobucket.com/albums/oo181/acharpen/Fostex_BK16/Fostex_BK16_BareWall_ContourPlot_235Hz_zps4423f020.png)
(http://i374.photobucket.com/albums/oo181/acharpen/Fostex_BK16/Fostex_BK16_BareWall_ContourPlot_315Hz_zps3de7b5f1.png)
Finally, here's some SPL contour plot outside the enclosure at 1.1kHz to get an idea of the directivity pattern (includes floor reflections):
(http://i374.photobucket.com/albums/oo181/acharpen/Fostex_BK16/Fostex_BK16_BareWall_Directivity_1kHz_Sideview_zps6072c49b.png)
(http://i374.photobucket.com/albums/oo181/acharpen/Fostex_BK16/Fostex_BK16_BareWall_Directivity_1kHz_Topview_zps33cf1212.png)
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Wow, excellent! You have finally made something useful with all those colors. :P
I deleted the 1/6 octave measurement on right speaker (the one located further from any walls), but I can tell you the following:
- Notable peaks were measured at 85Hz, 150Hz, 250Hz, and 1.7kHz. The simulation is incredibly close for the bass. The calculated theoretical peaks past the cloud region past 300Hz tend not to be strongly seen in the real world - I am not sure why - I've noted this goes for open baffle designs as well.
- Stuffing only in the area behind and the small crevice directly below the driver. Too much stuffing takes away from the dynamics of the speaker.
- The speakers on are stands, elevated about 10cm above the floor.
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Dave D./planet-10 of frugalhorn recommends CAT5, especially single runs of 24awg if you want to increase the output impedance of the amp a skosh to help tame any peaky upper-mids and add a little warmth in the mid-bass.
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This is what I found about the frugalhorns (dimensions starting on page 4):
http://www.p10hifi.net/FH/downloads/frugel-hornMk3-1v0-250212.pdf (http://www.p10hifi.net/FH/downloads/frugel-hornMk3-1v0-250212.pdf)
(In response to this (http://www.changstar.com/index.php/topic,841.msg20852.html#msg20852) by Arnaud)
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Applied the final fourth coat of Tung oil today, after burnishing with steel wool. (Sanded each in-between coat with 400grit sandpaper). Polished with rags. Last step will be to apply oil/wax for a final hand polish. My crappy low light slightly OOF pictures don't do the finish justice. Tung oil is not quite like lacquer. Instead, the oil hardens into a resin that is more into the wood rather than over it. This process probably takes a lot more effort than the old Japanese folks high on fumes working on the TH900.
The right speaker baffle has a more interesting grain pattern than the left. The panels reflect light differently depending upon the angle. The stands are the same wood, but not treated yet.
EQ settings tell me a supertweeter should solve a few things, if I can integrate it the right way.
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All this speaker talk makes think twice about planning a KGSSHV as this years main audio project.
Btw, what about genre bandwidth with a wide-bander? I'm actually thinking of building a 3 way floorstander.
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Wow, excellent! You have finally made something useful with all those colors. :P
I deleted the 1/6 octave measurement on right speaker (the one located further from any walls), but I can tell you the following:
- Notable peaks were measured at 85Hz, 150Hz, 250Hz, and 1.7kHz. The simulation is incredibly close for the bass. The calculated theoretical peaks past the cloud region past 300Hz tend not to be strongly seen in the real world - I am not sure why - I've noted this goes for open baffle designs as well.
- Stuffing only in the area behind and the small crevice directly below the driver. Too much stuffing takes away from the dynamics of the speaker.
- The speakers on are stands, elevated about 10cm above the floor.
Marv, thanks for the comments, indeed the speaker simulation feels much more rewarding than headphones because you can get sensible results with pretty much just a geometry amd basic driver mechanical properties. For headphones, it is so much trickier and without real material data and other physical properties, it's just a crap shoot to be anywhere close to real results (still is extremely valuable to get a handle on the physics though and key parameters, I learned a great doing stat diy simulations).
For the resonance at 1.7kHz, I wonder if it may be the first cone breakup? It's rather flexible fiber cone it appears so I wouldn't surprised to start seeing these from the midrange up. I could also investigate that further with a more detailed cone model (really just used a rigid piston with tuned Fs and arbitrary damping in the stuff I posted above because I was mainly after the horns resonances).
It could get even more interesting actually... If can convert the geometry to a parametric model, then an optimiser would automatically search for the optimal geometry to reach a particular target. It would take some effort on my side to setup the optimization, but that could be rewarding!
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Nice! Worked out well.
The exposed plywood edges and contrast bugs me though.
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EQ settings
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I'm going to look into local CNC routing. If it's not too much, I may even look into the Spawn designs since I have the space. Shipping on the flatpacks is a wee bit too dear since it's just a cheapy project for me.
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Latest picture of setup 3/15/2013.
- Integrated cheap Hsu STF-2 sub "REL" style. Will swap the driver out for something better and make volume or port tweaks accordingly if possible.
- Integrated Fostex T90 supertweets.
I'll note specifics in later posts.
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FR from sitting position. Octave and 1/3 octave smoothing. Still thinking of ways to integrate the sub better in terms of FR. The blending of the subs and mains is almost seamless though, something I don't want to give up. Hi-Fi is not simply flat FR, there are many other un-measureable aspects to take into consideration. Otherwise I would have stuck with my low efficiency extremely accurate active crossover system of yesteryear.
The ~10db downward slope from 20Hz to 20kHz is appropriate for measurements taken at the listening position. It would sound bright if the line were flat at the listening position. Right now, I think it's a little warm sounding. Maybe a broad 0.5 to 1db push down at 200Hz would do the trick.
I'm having a hard time integrating the tweeters. Again not necessary a matter of FR, but rather of seamless blending. I suspect the cheap Bennic caps are imparting some coloration. At least that's what I hope. I am worried that a horn tweeter just won't jive with a paper cone; but heck Fostex does recommend these T90 tweets with their drivers. Maybe I need the special Fostex caps.
BTW digital PEQ is applied in JRiver. There's no reason not to use it.
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I visited a guy who had speakers looking very similar to these, also using Fostex parts. but no clue what they sounded like as he wasn't finished... kind of curious now! looks very neat.
sorry for asking but how much does it cost to build something like this? like including a basic finish to make them look cuter? (no ponies)
also kinda off-topic but does the Air Motion Transformer exist in DIY form? very impressed with what I heard. though not sure if they're the best option. mainly just curious.
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The Hsu sub is integrated REL style. The secret to REL's blending is found in their instruction manual. REL sees the sub there more to augment existing speakers' at the low end and gradually blend things in. I had an older 12" VTF series sub from Hsu (and a REL Stadium series), but I could never blend that VTF sub in properly. The Hsu 10" STF-2, which I picked up for cheap, seems to fair better than the VTF.
Here is the setup / config:
- The speakers play full range. Absolutely no x-over here to mess things up.
- Behringer DCX2496 is used as the DSP for the subwoofer.
- X-over using LR 12db slope at a low 30Hz.
- Time delay of 0.80m. (Back from driver to mouth of horn is approximately 66in. Distance from sub to mouth of horn is 34in. 66-34 = 32in = 812m) I need to run step response measurement to make sure it's right, but I feel this approximately measurement is good enough. Without the time delay, we can hear the sub kicks in earlier than the mains.
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I visited a guy who had speakers looking very similar to these, also using Fostex parts. but no clue what they sounded like as he wasn't finished... kind of curious now! looks very neat.
sorry for asking but how much does it cost to build something like this? like including a basic finish to make them look cuter? (no ponies)
also kinda off-topic but does the Air Motion Transformer exist in DIY form? very impressed with what I heard. though not sure if they're the best option. mainly just curious.
~ $500 for the kit with stands. Just need a ton of clamps to ensure a precision fit and a lot of elbow grease to sand and shiny up the wood. The left speaker which I put together required some minor sanding on the edges to get a straight fit. After I figured it out, I got the right speaker pieces to fit together perfectly. The clamps, tools, sandpaper are extra. But I had some of those already lying around and borrowed some from a neighbor.
I believe Parts Express sells a Heil driver.
I'll provide a flow-chart of the system in a later post.
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Marv, for 30inch of separation, isn't the delay more like 2ms?
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Yeah, the 0.80m was "m" meters or 2.33ms.
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True, always felt that my current speakers have no dynamics at low volumes. It would be interesting indeed to hear the demerits of active crossovers. I tend to listen pretty loud in the living hall though when no one is around occasionally(80db average for short periods). The only thing in my experience that I can listen at really low volumes and be satisfied with is the HD800 as I have no particularly efficient speakers.
The disadvantages of active crossovers are simple: cost (and quality)
- Supposing a pre-amp feeds the active crossover (AXO) and the AXO splits the signal into bass, midrange, and treble, that means 3x amps. There are of course hybrid approaches such as using an AXO to split bass and above, and then using a passive for the mid/treble split.
- The AXO becomes yet another component in the chain, so the quality of the AXO becomes critical. I've stated that I feel passive crossovers suck the life out of music. Well AXOs can certainly do that do, especially if they are a bunch of op-amps slapped together. I think the only way I would do an AXO is with tubes (not because they sound lush, but rather because they provide clarity and immediacy which transistors and especially chips cannot.)
- One method I used in the past was to use the Behringer DCX2496 digital EQ/crossover. I took the low, med, high channels into 3 amps via a 6 gang pot. It was a good sounding system for cheap. Way better than the all Linn Activ system that I had previously owned, but for 30% of the cost. Ultimately, such a system would be limited by the quality of the DCX2496 because it also serves as the DAC. It's decent as a DAC. But not great. The DCX2496 however serves as a great subwoofer DSP processor / XO.
BTW, at this point, the only way I would do an AXO is this way:
(http://www.dnaudio.com/P4170762.JPG)
(http://www.dnaudio.com/P4170763.JPG)
Donald North is my hero. 'nuff said.
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Frequency response of the system after latest tweaks at listening position. I could make it perfect, but that just wouldn't be right. Measurements with 1/3 octave and one octave smoothing. Somehow I lost the 1/6 octave measurement. It was still impressive.
Couple of notes:
- Digital EQ correction for mains and supertweeters done via EasyQ VST plug-in in JRiver MC18.
- Corrections were minor -3db here, -2db there and here for the mains and tweeters.
- Mains play full range. Absolutely no XO in the way.
- Sub EQ and XO handled by DCX2496. There was a room resonance at 30Hz which required -9db notch. Also another resonance at 55Hz which required a -6db correction. @LFF: I completely re-did the sub.
- Only one sub, but I have a decent room to work in. Response does get screwy at different listening spots. I think two subs would help. Yes, that in-room listening positioning bass response!
- The treble roll-off is normal. Tweeters are highly directional at high frequencies. I have the two speakers angled inward so the intersection point is about 2 feet in front of the listening position. I found this arrangement best for the soundstage - so the left speaker avoids reflections from the left wall as much as possible.
(http://www.changstar.com/index.php?action=dlattach;topic=833.0;attach=3102;image)
(http://www.changstar.com/index.php?action=dlattach;topic=833.0;attach=3104;image)
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Wow, that looks amazing! Why not 'make it perfect'. I know perfect is impossible, but why not try to get as close as you can?
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Because one adds more and more PEQ filters without any discernible improvement in sound just to get a good looking line. I think I already have 5-6 PEQ filters on the mains, and even that is slightly overboard. Honestly, I could get away with just 2 or 3 PEQ filters and be happy. I'll post the EQ.
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EQ settings on the mains and supertweeters. These were the settings on the mains when LFF and Anax last heard the system. It's actually slightly brighter than I would prefer it; it is however more accurate. I would have preferred it maybe .075db lower in the lower treble. (Fractions of a db, especially if the EQ band is wide, make a huge difference - hopefully this gives people insight of where I am coming from when I shit on headphones with nasty ringing or simply horrible FR characteristics.
(http://www.changstar.com/index.php?action=dlattach;topic=833.0;attach=3106;image)
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Why?
So anyways, why did I want to do this? I heard a back-loaded wide-band horn speaker, the Voxactiv, at THE SHOW, and very much liked certain aspects of it: the immediacy, the purity of tone, the dynamics.
It sort of got me thinking because I had built many multi-way speaker systems, with PXO and AXOs (half of my parents' garage is dedicated to old speaker cabinets.) The AXO systems I built were super precise, detailed, clean, and powerful sounding, but because the AXOs were of crappy quality (cheap Digital XOs, cheap op-amps, etc.), they always sounded rather flat and clinical. As for the PXO systems (and I did not want to spend a fortune on $$$ inductors, caps, etc.), well, I felt that the PXO components always sort of sucked the life and dynamics out of the music. I had also built high-efficiency horn systems based on JBL compression drivers. Those were clean, loud, dynamic, but there was always the horn coloration, and it always seemed if the horns were more meant to beam energy through a crowd, like an alien-death-ray, despite any attempts at EQ.
Anyways, I think the headphone experience rather ruined me because it made me truly understand and appreciate how transducers without PXOs of any sort were really special in their clarity and immediacy - despite the fact that Grados have probably caused me some hearing damage. I started to get accustomed to very simple signal paths - with great DACs with great amps (no pre-amp in the way either.) I think the moment that really made me realize the shortcomings of PXOs was when I started to use the UERM. Great accurate FR, but I always felt the UERM to have a slight PXO veil and suckage-of-life, especially when not powered by an amp, compared to other IEMs with simpler 2-way or no crossover. Then I heard the active PP6, and realized that AXOs have short-comings in another way. The PP6 really reminded me of my prior AXO systems: super precise, detailed, clean, and powerful sounding, but... soulless.
So going back to the Voxactiv's, their big problem was a rising frequency response which pretty much made LFF ask: WTF guys? How can you stand that shit?
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How can you stand that shit?
So that's what got me really thinking. It many ways, the old-fart rich audiophiles are very primitive in thinking. They like doing things the hard way. Like finding some exotic tube, preferably from some fortress in Poland or central Europe, which only manufactures said tubes in the spring and fall (summer being too hot - no A/C; and winter being too cold - all energy must be used for sustenance), which has special properties in ameliorating the rising treble response.
To me, it's 2013. Computers can perform complex PEQ without even breaking a sweat. Packages like JRiver MC come with some great DSP tools, and if we don't like them, we can simply obtain other VST plug-ins. Now, there's the old-fart rich audiophile argument that EQ fucks things up, and I agree to some extent, but only when the EQ is extreme. However such an argument is bullshit anyways. A recording is usually EQ'd from the mic. The board could have global EQ. The mixing process involves EQ. The mastering process involves EQ. Your recording has already been EQ'd at least three or four times over. Any EQ with a delicate touch is not going to be a case of the cure being worse than the disease as so many old-fart rich audiophiles would like to believe. I'm sure there's a reason why HiFi equipment doesn't come with tone controls anymore: that $5K amp is too bright, the $10K amp will fix your problems.
Knowing how easy it is to apply PEQ at the source rendering level changes a lot. It put my fears to rest of any screwy frequency response behavior of wide-range back loaded horns without the use of a crossover circuit.
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It works
So anyways, the darn experiment worked, much better than I would have hoped. It turned out the comb effect from the interaction between the mouth of the horn and the speaker driver wasn't that bad and was predictable enough from various angles to be EQ'able. (We can still see vestiges of it in the FR graphs.)
The bass group delay from the horn in relation to the mids and treble was not discernible with the 6' BK-16 kit. The 8' Voxactiv's we heard at THE SHOW had a very discernible bass delay with much of Tom Wait's lower register appearing to come out from the horn fractions of a second before the driver. Anax and I pondered if perhaps the Vox's much longer horn path caused this effect. I will say that the 8' Vox was more dynamic and faster sounding. This seems consistent with others who have built the 8' Fostex kit. What makes speaker building fun is that there are a lot of compromises to be made. Decisions are never easy. Improve one thing, lose on another.
So anyways, here is a description of the system setup:
- POS Dell Core 2 Laptop feeds PSA PWD2DAC via USB. JRiver MC18 is used to resample x2/x4. EasyQ is used to EQ Mains/Tweeters
- PSA PWD2 DAC feeds the Schiit Mjolnir via generic XLR balanced cables
- Schiit Mjolnir 3-pin XLR "headout" jacks feed the mains (fostex fe166 drivers) - absolutely no crossover or other shit in between
- From the terminals of the mains, single strands of Ethernet cable feed the Fostex T90 supertweeters with one cheapo 0.22uF Bennic cap in series.
- Schiit Mjolnir 3-pin XLR "preout" jacks feed in the analog inputs of the Behringer DCX2496.
- Behringer DCX2496 feeds the cheapo Hsu STF-2 subwoofer's plate amp. Subwoofer PEQ/XO/delay is performed by the DCX2496.
Costs:
- $400 POS Dell laptop
- $2000 ($800 alternate DAC)
- $750 Schiit Mjolnir Headphone Amp
- $500 (Madisound BK-16 Fostex fe166 kit - you gotta put it together)
- $200 Behringer DCX2496 DSP EQ/crossover
- $380 Fostex T90 supertweeters (optional)
- $370 Hsu STF-2 sub (optional)
- Cables, adapters, soldering iron, clamps, wood glue, tung oil finish, etc. are extra.
This setup sounded better overallthan any other moderate SPL setup at the 2012 SHOW. I shit you guys not. I'll let LFF, Anax, or Ultrabike (later) to attest to that. It is hard to beat custom measurements and EQ though. It's all about setup and integration, not high priced components. Add the following to be able to do measurements:
- $150? ARTA
- $55 Behringer ECM800 microphone
- $99 Microphone preamp
- $59 Soundcard
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Very interesting read Purrin! Just 2 questions if you don't mind:
-How do you measure your speakers? What equipment, position, software etc. do you use?
-What would you recommend the non-DIY'ers?
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Very interesting read Purrin! Just 2 questions if you don't mind:
-How do you measure your speakers? What equipment, position, software etc. do you use?
-What would you recommend the non-DIY'ers?
- I use an ancient version of commercial measuring system CLIO running on a Pentium 4 PC. I have started to augment the CLIO with ARTA - indicated above.
- I would recommend that non-DIY'ers first learn how to use a soldering iron. No pain no gain.
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what soundcard are you using?
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Some cheapo generic soundcard from the 90s that came with the CLIO kit.
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Really impressive, Marv. Amazing sound on the relatively cheap.
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The old type of audiophiles are rather stupid in a sense, they abhor PEQ and other DSP stuff but are somehow able to live with crappy drivers/resonances, we get them a lot in the headphone community as well.
That being said, thanks for elaborating on the AXO stuff, the only way I see that AXO is viable has always been on the digital side but none of the dacs are that great if they could do crossover splitting. Guess that in the interest of lower cost, will be sticking on the passive side of things for a while.
Great job purrin, very nice results. Would be fun to see CSDs if you can get anything meaningful though.
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Very nice work. One thing I've always wondered about is a wide-bander in a flow resistance enclosure, rather than a horn or traditional box type setup. Has anybody ever tried that? In theory at least, no crossover combined with the room nullifying effects of a FR enclosure with maybe a bit of EQ would be the best of all worlds, requiring little more than maybe a few corner traps where the FR effect doesn't work.
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I don't think anyone has tried that. These HE wide-banders tend to have very little x-max. I would worry that the flow-resistance enclosures are too close to open baffles - any cone I've seen mounted on a open baffle tends to have excursion like crazy. I know John K's Nao Note II RS uses H frames instead of straight open baffles (I don't know if he stuffed anything inside the back of the H frames), but this was only for the woofers.
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What I was thinking is something like an Omega Super 6 that would run full range from about 45ish Hz to 18Khz, in a flow resistance box to cancel out the side and rear wave. Two subs I guess with some bass traps or EQ or both could be used to fill in the bass response where FR enclosures don't work anyway. The one FR speaker I'm familiar with is the Krypton, which is a 3-way, with two 8" mid-woofers that work from 160-1200Hz. I don't know how much bass output the Super 6 would lose if the box was a FR instead of just ported.
I suppose one possibility would be two opt for a two-way setup, using a method like Reference 3A where the mid-bass driver is driven without a crossover, with a single cap acting as a high-pass filter.
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Yeah, the use of x2 8' drivers would work better. Much larger surface area than one tiny 6', so less excursion for each driver. I don't think a Super 6 type of design (one 6' cone) in a flow resistance enclosure (I guess it's similar to a U-frame with stuffing in the back) would work well at even moderate SPL. The ported boxes or even rear loaded horns really help load the cone to keep its excursion from going crazy.
Instead of x2 8' drivers (I am not a big fan of MTM designs), I could do x4 8' drivers in an stuffed U-frame with a super tweeter in the middle, and then lend off the bass duties to a woofer. Then again, Donald North could have beat me to it:
(http://www.dnaudio.com/copenhagen2003_1.jpg)
It's a great idea you have though Dave. Now you've gotten me excited. (P.S. Dammit, stop giving me ideas.)
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SYSTEM UPDATE:
BTW, on a related thought... I realized how dumb it was for me to notch the 30Hz room mode on the subwoofer DSP unit rather than in JRiver (where the EQ also affects the mains.) I have now implemented the 30Hz room resonance notch in JRiver. This also relieves the 6' Fostex drivers from trying to reproduce bass notes it couldn't reproduce in the first place (I'm sure the little driver was playing 60Hz and 90Hz tones - 2nd and 3rd order distortion - instead of 30Hz.) This seemed to have made a huge difference in the clarity of the driver and eliminated some odd noises from the horn (the horn is tuned to 50Hz, and the driver Fs is at 50Hz).
I tried doing the same with the 55Hz room mode, but in the end, I've decided to still let the mains handle it for better mains and sub integration. This may change once I get a better subwoofer in because the Hsu is not exactly a tight sounding sub.
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That's a cool looking speaker, but does the woofer have enough baffle? Seems like it would interfere with itself with so little baffle on the sides.
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I'll summon Donald to see if he can answer some questions. Woofers in open baffles are almost always EQ'd to adjust for the roll-off. Given the size (18') and excursion capabilities (max 75mm p2p) of that Aurasound monstrosity, the EQ requirements would be less extreme. The Qts .45 of that woofer (if it is the NS18-992-4A) would lend itself to an open baffle design as well. I wonder if the compensation circuits are part of that tube AXO box.
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On my DNA Sequence speakers, I used a custom version of the Aurasound NS15-992-4A, which has a 20Hz Fs and 0.5 Qts. Their NS18 will also work beautifully as a dipole woofer. For my speakers I intentionally made the baffle narrow to minimize baffle resonance problems and apply EQ to flatten the bass down to 30Hz.
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Those look really nice Donald :)
Marv, any mic pre recommendations?
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Anything that will take an SE output (the Behringer mic - I think it's SE), and with phantom power. Luis may know better than I. He did make a custom pre-amp from high quality parts for his binaural head though.
http://www.musiciansfriend.com/pro-audio/rolls-mp13-mini-mic-preamp
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Sweet!
Are you planning to stick with Schitt, or thinking of doing some amp rolling?
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EC2A3 comes to mind if Craig will let me steal one of them. The intent of such as design was to make use of the Levi. However, Schiit's upcoming Statement hybrid also comes to mind. Anax's S7 (tubes rolled for HD800) didn't work out too well and lacked sufficient gain (and probably power) to get moderate-high SPL. My main concern with tubes is sloppy bass. A Nelson Pass design would be interesting, but the NP integrated amps cost more than the entire system.
I am very happy with the Mjolnir right now. That circlotron circuit got's something special.
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Ive heard good things about the Pass Integrated. I had an Aleph 3 before and that one at 30wpc sounded more powerful than 100+wpc onkyo and sony amps :)
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EC2A3 comes to mind if Craig will let me steal one of them. The intent of such as design was to make use of the Levi. However, Schiit's upcoming Statement hybrid also comes to mind. Anax's S7 (tubes rolled for HD800) didn't work out too well and lacked sufficient gain (and probably power) to get moderate-high SPL. My main concern with tubes is sloppy bass. A Nelson Pass design would be interesting, but the NP integrated amps cost more than the entire system.
I am very happy with the Mjolnir right now. That circlotron circuit got's something special.
Ahh of course, forgot about the Levi.
I was mostly thinking DIY keeping in line with the speakers. Pass becomes much more affordable
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This thread has really sparked my interest in some of these kits/plans. I know a few had mentioned a group buy or diy with some cnc work. I would definitely be in if we can all agree on what we would like.
If it came to diy and work from a plan, I have a friend a few doors down with a cnc as well as a machinist if needed. I can also do my part as I have a shop and can store/ship material.
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This looks like a fun DIY project. How does the rear loaded baffle compare to the design of the Moth Cicada that you posted in the other thread? Do you think the fostex drivers would work in a bass reflex cabinet design like the Cicada or would you be losing too much of the bass presence?
Also nice to hear that there isn't a discernible bass delay, seems like a common problem for the rear loaded baffle system. I was worried it would take too much technical knowledge for me to try to compensate for that.
One more thing, how did you integrate the supertweeters into the system? I didn't think you wanted to use any crossovers.
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Good going!
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This looks like a fun DIY project. How does the rear loaded baffle compare to the design of the Moth Cicada that you posted in the other thread? Do you think the fostex drivers would work in a bass reflex cabinet design like the Cicada or would you be losing too much of the bass presence?
Also nice to hear that there isn't a discernible bass delay, seems like a common problem for the rear loaded baffle system. I was worried it would take too much technical knowledge for me to try to compensate for that.
One more thing, how did you integrate the supertweeters into the system? I didn't think you wanted to use any crossovers.
I do not like the bass from the Cicada. It very much sounds like the typical ported bass in a box - keeping in mind this speaker was from a prior era - right around the time when speaker companies started to put more effort toward making properly braced and re-enforced cabinets.
The BK-16 cab I like. The cabinet is very vibration free - doubled thickness baffle in front and back - the internal panels of the horn also providing mucho bracing. The length of the back horn seems short enough to not cause any notable delay in the bass. There's still some horn coloration, but it's much better than some of the larger back loaded horns I've heard.
The bass is very open with the BK-16. Not boxy at all. I still need to hear an open baffle bass speaker like Donald's.
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Marv, if your room limits how far away from the back wall you can get with your speakers are there any options that are more forgiving/allow you to place pretty close to the wall? Or, is something like the BK-16 going to really start to suffer if you push it too close?
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You should be OK with the BK-16 up against a wall since the horn does help direct a significant amount of mid to high bass forward (and low bass is non-existent). In other words, it's much more immune to the muddy bass effect when placed against the wall because of the directivity of the horn. I pull them out for better stereo imaging. The stands in my opinion are necessary.
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You should be OK with the BK-16 up against a wall since the horn does help direct a significant amount of mid to high bass forward (and low bass is non-existent). In other words, it's much more immune to the muddy bass effect when placed against the wall because of the directivity of the horn. I pull them out for better stereo imaging. The stands in my opinion are necessary.
Interesting. Why do you think stands are a must?
I have the Fostex BK-12 cabinet (built myself, didn't get the kit) and I was thinking about sitting them on a piece of plywood and isolation spikes. I suppose building a pair of angled stands wouldn't be that much harder.
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- Need to lift BK-16 off floor to prevent mid-bass bloat, unless strong mid/upper bass is your preference. The floor will reinforce the bass. Placing against the wall (in the context of Ship's question) will also reinforce the bass.
- I can't say for the BK-12, which is different from the BK-16. It also depends on the drivers used which will result in varying responses.
- Stands are not a necessity. Angling is not a necessity. Lifting the BK-16's horn up from the floor is a necessity IMO. Whatever method is used to lift the mouth of the BK-16 horn up from the floor should be fine as long as it's sturdy.
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I've been looking into local options. Madisound's price for the kit is very reasonable.
A friend that owns a furniture company says the cost savings to route a box the size of BK-16 wouldn't be that much. And the larger enclosures like Kirishima or Victor will not be cheap.
The BK-16 isn't viewed that favorably on DIYA (most saying it's a very old design), but they commenting on it without EQ.
purrin do you have any thoughts on EnABL? It seems like voodoo to me... and I'm not too trusting of the guy that came up with it.
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I've been looking into local options. Madisound's price for the kit is very reasonable.
A friend that owns a furniture company says the cost savings to route a box the size of BK-16 wouldn't be that much. And the larger enclosures like Kirishima or Victor will not be cheap.
The BK-16 isn't viewed that favorably on DIYA (most saying it's a very old design), but they commenting on it without EQ.
purrin do you have any thoughts on EnABL? It seems like voodoo to me... and I'm not too trusting of the guy that came up with it.
There are better box designs than the BK-16. I believe the box was meant for an older driver, the fe165 which is no longer available. It just happened that the fe166 sort of worked in it. The FR of the BK-16 is very midrangy with a fairly 3db broad bump around 1k.
The EnABL stuff definitely smells like voodoo. I would like to see measurements.
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I think I am going to start a Vulcan when I return to town. Being in the woodworking industry as well I can certainly agree that the fostex kits are well priced.
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I think I am going to start a Vulcan when I return to town. Being in the woodworking industry as well I can certainly agree that the fostex kits are well priced.
I'm not sure if you're planning to EQ or not, but from my research it seems like many people dislike the 8" Fostex drivers, saying they're too shouty.
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I believe he had recommended the sigma driver with this and a tweeter, I was also thinking about the cornscala. Are you still leaning towards the Victor?
EQ and follow this thread directly, I have a lot to learn but look forward to starting the process.
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I believe he had recommended the sigma driver with this and a tweeter, I was also thinking about the cornscala. Are you still leaning towards the Victor?
EQ and follow this thread directly, I have a lot to learn but look forward to starting the process.
I am more than likely just going BK-16 since I don't have a large enough room for Victor and I plan to EQ them. Also I feel more comfortable knowing there are some baseline EQ settings for the BK-16 (though I do plan to measure them) and that I can bug purrin more shall noob questions arise :&
But I'm probably only going to start this in the fall.
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I'll take more baseline measurements of this kit to assist you guys.
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Please do. I'm interested to see how bad the "shoutiness" really is on the larger full-range drivers.
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I stumbled upon this kit from parts express http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-702
(http://www.parts-express.com/images/products/hires/300-702_h.jpg)
(http://www.parts-express.com/images/products/large/300-702_li.jpg)
I know this is an MTM transmission line , one of the DIYrs used these speaker boxes with the Merrill DCA5.5 full range driver as the box volume calculations are reported to work well for the driver.
$260 with free shipping sounds like a great place for an experimenter to start
..dB
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Looks decent enough for the price. My audio project for the summer is to put together Troels Gravesen 3-Way Classic bigger-than-bookshelf speakers.
Also one of the local diy guys is about to finish designing a pretty promising speaker amp, will whip up that as well.
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Wow, $260. Transmission line too!
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I stumbled upon this kit from parts express http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-702
I know this is an MTM transmission line , one of the DIYrs used these speaker boxes with the Merrill DCA5.5 full range driver as the box volume calculations are reported to work well for the driver.
$260 with free shipping sounds like a great place for an experimenter to start
..dB
Don do you know about Lynn Olson's Ariel? http://www.nutshellhifi.com/Ariel.html
It looks very similar to that, though Lynn's speakers used Vifa mids and a Scanspeak tweeter. From what I've read they are supposed to sound very good. I think Living Voice used a similar arrangement (maybe even drivers) for the Avatar.
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i never bothered with the EnABL with my FF85K since they're so well behaved in the upper mids. there's been gallons of ink spilled on the subject and i know there's measurements floating around over at diyaudio. Bud Purvine created the process. i googled "bud purvine enabl" and came up with this interesting article: http://www.enjoythemusic.com/diy/0310/modifying_ff85ken.htm (http://www.enjoythemusic.com/diy/0310/modifying_ff85ken.htm). if you're EQing then maybe this would be a waste. i suspect that the process has a subtle effect, but only to peeps who "know" the sonic sig of the particular driver/cab well.
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Don do you know about Lynn Olson's Ariel? http://www.nutshellhifi.com/Ariel.html
Yeah , I started building a set but the boxes became a nightmare without a workshop and assembling in the apartment. I found a guy who had a spare set of speaker boxes but he would only do local pickup and it was too far from where I lived at the time.
I managed to hear a pair at VSAC , they do sound very good.
..dB
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Don do you know about Lynn Olson's Ariel? http://www.nutshellhifi.com/Ariel.html
Yeah , I started building a set but the boxes became a nightmare without a workshop and assembling in the apartment. I found a guy who had a spare set of speaker boxes but he would only do local pickup and it was too far from where I lived at the time.
I managed to hear a pair at VSAC , they do sound very good.
..dB
Does VSAC still happen? I was searching for dates/info a few weeks ago and didn't come up with much recent news.
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I built a pair of Lynn Olsons Ariels about 10 years ago. They sounded pretty good with my tube amp. A lot of fussy routing though, you'll want a CNC router to cut all those precision grooves on the panel sides.
I also managed to build a pair of Bottlehead Straight 8's in 2007. I still have those and love them. Too bad you can't get the tweeters for that design anymore.
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Per Purrin and this thread, eventually decided to start with a Victor. Was able to squeeze out a mock up before leaving for the weekend. Think I got a handle on it, will build a completed walnut pair when I get back. Then will attempt to tackle eq and room, really excited about the potential, thank you.
(http://i1317.photobucket.com/albums/t632/strugglesness/victor_zpsd9564396.jpg)
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I built a pair of Lynn Olsons Ariels about 10 years ago. They sounded pretty good with my tube amp. A lot of fussy routing though, you'll want a CNC router to cut all those precision grooves on the panel sides.
I also managed to build a pair of Bottlehead Straight 8's in 2007. I still have those and love them. Too bad you can't get the tweeters for that design anymore.
Cool! Have you read the DIYA thread "Beyond the Ariel"? Looks like a really interesting speaker he's come up with.
Looks great struggles. Looks like you found a DCX? (you sent me a message on Headfi)
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I have been trying to track down a used one with no luck, ended up just snagging a new one from Amazon to use with 2 stf-2's I found for cheap. Hope to give it a go next week and do what I can to tame this room.
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(http://i1317.photobucket.com/albums/t632/strugglesness/victor_zpsd9564396.jpg)
wow I like this one. talk about maximizing those drivers :)
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Got itchy after the updates yesterday and saw the talk about this wittle guy (DNA Horn with Aurasound $3.60 driver), what the hell, drivers should be here Friday.
(http://i1317.photobucket.com/albums/t632/strugglesness/IMG_20130507_175338_920_zps1a1d38db.jpg) (http://s1317.photobucket.com/user/strugglesness/media/IMG_20130507_175338_920_zps1a1d38db.jpg.html)
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Wow, that's gotta be nice (the big Victor). A much better and proper horn design than the BK-16. Let me know how it goes.
LOL, I just noticed you are using a Mjolnir to drive it?
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Lol, yea, I could not resist, very impressive. :)p7 Using a Linn Classik at the moment, just waiting for the Levithan and a preamp.
For now just fiddling around, the current room is rough, 12x10, but I will take it! Having a lot of fun, learning a lot. T90a's arrive this week from b/o so that is the next thing to tackle.
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Do you think Jason has seen you guy's pictures using the mjonir as amps? What do you think the chances are of Schiit building speaker/analog stuff?
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Do you think Jason has seen you guy's pictures using the mjonir as amps? What do you think the chances are of Schiit building speaker/analog stuff?
Well, they did Sumo at one time, it will be hard seeing them go back to doing speaker stuff.
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If Schiit could make an affordable 50W speaker amp I'd be all over it. I'd even settle for 20W.
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The Statement amp will have speaker taps if I recall correctly.
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Indeed you do recall correctly.
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struggs how are those Wodens with no EQ? I'm thinking I might have to go the no EQ route, since I'm mostly listening to vinyl these days. Primarily concerned about the upper mid shout, the Frugelhorns don't look too bad in that regard either.
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I moved my setup to a new room with walls fairly close on the left, back, and right (see pic.) In the previous room, the speakers were located several feet from the back wall, with the right wall much farther from the left (the right speaker was about 6' or more from the right wall.
I would say that this new room is probably more "normal" - with speaker placement to the back wall at ~18". In this configuration, the only gross EQ adjustment (past the bass range, which is always messed up) I needed to apply was +2.5 at 7kHz with a Q of 4 (from memory, I will check settings later).
This is in contrast to the previous room where I bumped up 8kHz similarly and also had to push down a broad 1kHz bump. I believe the placement closer to the back walls (and having left and right walls closer together) helps reinforce the bass and lower mids in relation to 1kHz. I was rather surprised a how little tweaking with the EQ was necessary. I'm sure with a tweaked X-over on the tweeter, no EQ would be required (other than surgical stuff in the bass or to correct for driver peaks)
(the room is still under construction - still testing a few things for the HT)
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Here's the FR via RTA at prime listening position. 1/3 octave. The tuning is slightly different from the previous one. This is more neutral. The other one was slightly laid back. I did EQ bass modes (didn't spend as much time was I wanted on it). Gross and surgical (for driver anomalies) EQ were also applied (the surgical EQ doesn't make much of a difference to my ears other than make the graph look more linear.)
Treble roll-off in the last octave is normal since the microphone is pointing forward and probably offset from the tweeter about 25 degrees. Point the mic directly at the speaker and the roll-off goes away.
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BTW, I don't think you will have a problem with shout with the fe166s which are the 6" drivers. The 8" drivers tend to be more problematic.
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struggs how are those Wodens with no EQ? I'm thinking I might have to go the no EQ route, since I'm mostly listening to vinyl these days. Primarily concerned about the upper mid shout, the Frugelhorns don't look too bad in that regard either.
Vinyl here also, no eq at the moment. I do not find these shouty either, I really like the speaker though a bit tall, I mounted a small platform for the T90's just above the full range. I am still waiting on my amp so it has been difficult to see their full potential.
Purrin that looks great, I was curious about your thoughts on the T90?
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I was considering building an RL circuit to shelve the lower treble a bit on my FE126En, but I think my receiver's tone control is working good enough to control it. The idea of having nothing but wire in between the driver and the output gets me excited :-DD Also might try playing with the throat damping a bit more. I'm going to seal cabinet soon, so there will be no going back after that.
My own space is fairly similar to your new one purrin. 2' from the back wall. 5' from the sides. But I listen about 8' away (farther than you it looks) and there is a back wall 2' behind my head. Using test tones (chromatic scale seems to be the best for discerning) it sounds fairly even to me outside the brightness in the treble. I think it's around 5k-ish. The shoutiness (1k-2k) seems to be mostly gone to my ears, where it was unbearable when I first started listening. Go ahead and crucify me, but I think these Fostex drivers have a knack for break-in or whatever you want to call it. I don't think it's purely psychological because I can go back and forth between my more neutral 2-way and it really seems to me that the shout is gone. It's still forward, but not shout-y. Like a Grado without the ringing I guess.
Before you guys lecture me, I know ears are a shitty way of evaluating flat FR. I'm finally going to pull the trigger on that miniDSP mic so I can ground myself while I finish tweeking. And hopefully contribute some plots to this thread.
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struggs how are those Wodens with no EQ? I'm thinking I might have to go the no EQ route, since I'm mostly listening to vinyl these days. Primarily concerned about the upper mid shout, the Frugelhorns don't look too bad in that regard either.
Vinyl here also, no eq at the moment. I do not find these shouty either, I really like the speaker though a bit tall, I mounted a small platform for the T90's just above the full range. I am still waiting on my amp so it has been difficult to see their full potential.
Purrin that looks great, I was curious about your thoughts on the T90?
Are there any complex cuts that need to be made for the Victor, or bending wood?
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No bends, the internal structure is made up of butt joints and few transition pieces that are mitered to the outer frame and filled. The only detail is the inset of the driver frame with a back bevel on the opening. Feel free to message me, more than happy to help where I can.
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Also might try playing with the throat damping a bit more. I'm going to seal cabinet soon, so there will be no going back after that.
I think it's around 5k-ish. The shoutiness (1k-2k) seems to be mostly gone to my ears, where it was unbearable when I first started listening. Go ahead and crucify me, but I think these Fostex drivers have a knack for break-in or whatever you want to call it. I don't think it's purely psychological because I can go back and forth between my more neutral 2-way and it really seems to me that the shout is gone.
I tend to believe that there is a little break-in period. (I do wonder if the new measurements reflect both the new room and effects of break-in.) The damping behind the driver plays a huge role too. The BK-16 kit box has a the back wall fairly close to the driver, so sound waves (typically the midrange) will tend to bounce back from that wall through the driver and outward (it happens with any box design). As to how much or how far to stuff, it seemed to be balance between absorbing the reflection and transient response. I'm currently only using a wad of acoustic fiber behind the driver. I initially had more fiber in there: lined the inside surfaces and partially stuffed into the horn, but I pulled out it because the speakers sounded too dull with that much stuffing. I plan on playing with other materials.
Also if there are any cavities or spaces, best to fill with sand. That did wonders. Weighs down the speakers and brings about more precision and articulation to the sound. Additional, consider Dynamat or similar materials applied to the back of the magnet and on the stamped frame / basket of the driver. I also stuck Creatology foam on top of the Dynamat material.
For my next project, I plan on either adding foam or rounded wood trim to the corners / bends of the horn.
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Right now I've got the whole driver chamber (throat) packed with foam. Probably couldn't add much more, so there's only one way to go. Mass-loading sounds like a good idea; this cabinet seems to be especially resonant, but that's how horns work I guess. Also I need to get to work on a pair of stands. I'd get the Madisound ones, but they look a bit big for the BK-12. I'd like to do all of this with measurements of course.
Why bother with the horn's bends? What's that supposed to do?
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Mass-loading sounds like a good idea; this cabinet seems to be especially resonant, but that's how horns work I guess.
No No No! Cabinet / horn should not be resonant at all. The BK-16 kit was double walled on the front and back. Even without mass-loading with sand, the darn box was extremely non-resonant. I'm sure its compact size also helps a lot.
Why bother with the horn's bends? What's that supposed to do?
From what I've read, less irregularities with the FR because sound waves don't bounce as funny. Less "horn" coloration. The horn designs are new to me, I so can't say for certain until I try things out. Will keep you posted on future projects.
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It's probably just the dowels that I have in place then. Like I said, I still haven't sealed it.
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The damping behind the driver plays a huge role too. The BK-16 kit box has a the back wall fairly close to the driver, so sound waves (typically the midrange) will tend to bounce back from that wall through the driver and outward (it happens with any box design).
Why use a box then? Go unipolar or bipolar fully open if you have a nice room and sensitivity to spare...
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Why use a box then? Go unipolar or bipolar fully open if you have a nice room and sensitivity to spare...
Because the goal of the project was to specifically make a rear-loaded horn speaker, see how well it would work with flea powered tube amps, and learn from a few things from that. The goal of the project was never to make a speaker free from internal box reflections.
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Have you tried making any open baffle speakers before AS? I was thinking I could get a pair of these Eminence Alpha Drivers and "roll" them in with my Fostex. The cabinet would be easy for sure.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=290-407
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Tried making? No, not really. Only closed classic boxes got really made out of cheap speakers, because somehow nobody wanted the cheaper woodwork/more expensive driver open baffle combination.
A hybrid would work best, open baffle for mids/highs with a boxed woofer. Open baffle woofer will excite all kinds of room modes making the sound a mush, not something I'd recommend.
This Eminence woofer would do nicely as the woofer part. Seems it requires a seriously large vented damped cabinet though, otherwise bass extension will suffer.
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Have you tried making any open baffle speakers before AS? I was thinking I could get a pair of these Eminence Alpha Drivers and "roll" them in with my Fostex. The cabinet would be easy for sure.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=290-407 (http://www.parts-express.com/pe/showdetl.cfm?partnumber=290-407)
I've seen other people make OBs with that woofer, but I've never heard it. The driver seems efficient enough with decently low Fs. The high Qts also tends to work in favor of OB. Unfortunately, the Qts (and Qes) is high (like abnormally high). Meaning the magnet is way too way small. So I would have serious doubts on how good the quality of the bass would be (in terms of control or tightness). There's a reason why those Alpha woofers cost almost a dime a dozen.
The only woofers I would consider for OB would be the Aurasound NS-1818", the Peerless XXLS 12" (doubled up), or maybe some from the Dayton Ultramax/Reference line.
Linkwitz and others have made an argument that OB is better for rooms because there is an area of cancellation parallel to the plane of the baffle. The polar output of OB is basically a figure-8 pattern. With a slight H or U frame arrangement, maybe a hyper/super cardioid.
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I brought up that woofer because it seems to be the popular choice for open baffle configurations. At least over on diyaudio. High Q and high sensitivity.
I've heard all sorts of terrible things about open baffle woofers. But I've also heard a lot of bad things about full-range designs and that has turned out OK for me. So I'm willing to try anything once I guess
I figure if I get those woofers and the open baffle sounds like shit in my space, I can always scrap it and move them into a standard cabinet. Dual subwoofers :)p3 I'm really just looking for a way to get a bit better LF response and play with things. That's also why I need that omni mic soon. The BLH is OK for a lot of music, but it sounds weirdly colored sometimes as purrin mentioned before.
I'm a bit skeptical about the woofer too actually. Fairly cheap and seems to be mostly oriented towards pro-applications (bass guitar amp cabinets). The other woofers, anything more expensive really, would break my budget though. Again, I'm not worried about time spent building cabinets or tweeking. It's the driver cost that's gonna kill me. If it sounds like ass, I'll be sure to let you guys know.
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Well, they are cheap enough - so no loss. What's more important is that you get to learn - hands-on. Hands-on >>> reviewing design specs, un-informed speculation, or computer simulations.
Let me know how it goes.
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No bends, the internal structure is made up of butt joints and few transition pieces that are mitered to the outer frame and filled. The only detail is the inset of the driver frame with a back bevel on the opening. Feel free to message me, more than happy to help where I can.
Cheers, I will send you a message soon.
OJNeg I have heard a pair of speakers that used those Eminence woofers "modified" by the manufacturer. Hammer Dynamics were the company, they sort of fell off the planet. They were nice sounding speakers, but I can't really say more than that. No idea how they would perform in OB.
After seeing measurements of Radian Le Cleac'h horns these are the speakers I'm most excited about. But bare minimum $6k with the drivers and custom horns. And they'd be the size of refridgerators. 102 db/w sensitivity, delicious :)p1
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This type of build is really starting to interest me... I'm going to build some 9W mono-blocks and these should be efficient enough.
Are these Fostex used in a lot of DIY stuff? Don't answer that, I'll google it! :D
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Which 9W monoblocs?
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DocB Paramounts.
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Do some The Wire LPUHP amps instead! Should be more powerful!
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Power is not the point of the project.
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Tubes are tubes, bet The Wire shows some pretty promising THD figures. I'm considering it for powered desktop speaker duty.
That is if nice distortion figures are what you are shooting for.
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The Wire looks cool. Have fun with that.
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Chris, I'm sorry, we can't let you build the paramounts. You must build the Wire.
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Honestly, DIY options are worse than headphones. There are so many cool builds out there, it's hard to figure out what to do! Fun, fun. And of course, Purrin has me thinking I could build speakers! Another gazillion options to consider!
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Very nice, the Paramount looks like a great value. You could stick a pair of FE126En (the ones I have, $50 a piece) in a small bass-reflex cabinet and have a kick ass little system. Your 9W would have more than enough power to drive those real loud. Just another idea for you to ponder.
http://www.bottlehead.com/ (3rd and 4th picture down)
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I like! I don't want to build anything too large right now as I'm only here for a few years and don't know what my space will be like when I get back to the US... something like that I can do and always have a use for! Danke.
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Finished with the Tung Oil and have 3 coats of gloss on right now. I don't think I need any more gloss, but I guess I can always add more down the road.
I also sealed the cabinet and took out a bit of Acousti-Stuff (but tried to spread it more evenly) a la Purrin's recommendation. Of course I open the cabinet to find...
(http://i.imgur.com/nSSYCB7.jpg)
I don't know what the heck I was thinking trying to hold 'em with tape. I guess that's where a bit of that horn coloration was coming from. It was subtle to be sure, but I couldn't help thinking something was wrong with the cabinet. I thought it was just the dowels being weird but this might have done it too. Fixed 'em in with glue this time.
Although the cabinet is sealed I actually could still tweak the damping up there. All I have to do is awkwardly reach up the mouth of the horn and rip the pads off. I'm not too worried about that actually.
According to SpeedPost, my mic has arrived in America. Once I get it and figure out how to work it with REW I'll throw some plots up. :)p2
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Three coats is good. Re-coat a few months later if necessary. I usually finish with a wax made up of partial tung oil.
Use a nail gun. LOL. Felt is probably better than foam for lining inside walls.
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Purrin has me thinking I could build speakers!
or you could just buy a pair http://www.audiocircle.com/index.php?topic=118476.0
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Those are the ugliest speakers I have seen in a while.
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i love my Fonkens - uFonkens and uFonkens^2 to be exact. the ^2 sit in my 'puter-fi rig and the regular single driver FF85K uFonkens for watching movies in the family room. good for near field and small rooms as long as you're not a bass-head.
http://i23.photobucket.com/albums/b353/fishski13/uFonken2/017_zps71a8caa4.jpg (http://i23.photobucket.com/albums/b353/fishski13/uFonken2/017_zps71a8caa4.jpg)
http://i23.photobucket.com/albums/b353/fishski13/uFonken2/013_zpse45c7071.jpg (http://i23.photobucket.com/albums/b353/fishski13/uFonken2/013_zpse45c7071.jpg)
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Ha, thanks for not painting them green.
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Tubes are tubes, bet The Wire shows some pretty promising THD figures. I'm considering it for powered desktop speaker duty.
That is if nice distortion figures are what you are shooting for.
Let's see IMD and harmonic distortion broken down by what order they are for THE WIRE
I have a headphone amp sort of based around the S/E version (minus the DC offset) and it is a bit above average for its cost. Most of it is just the hype qusp built around it.
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Ok, I'm as giddy as a schoolgirl right now. My mic just came and it is sooo kewl! I've just been walking around my house and back yard with my laptop in hand to measure the ambient sound levels. This is probably the most fun $100 I've spent in audio so far.
(http://i.imgur.com/m4rkezp.jpg)
And just for reference:
Room:
- 15' front to back
- 14' side to side, but there a large opening on the left side (where the picture is taken from)
- Ceiling is sloped from side to side
Speakers (measured from baffle):
- 4.5' from the front wall, 10.5' from back
- 5.5' apart, toed it ~15 degrees
Mic:
- 4' from the back wall
- Forms a ~6' equalateral triangle with speakers.
- This is only about a foot closer than where I normally sit. But I am not on the same vertical axis as the mic (a bit above obviously)
If anyone sees any faults in how this is set up please tell me.
So questions for Purrin (or anyone): What kind of sweeps do you use? Do you do multiple sweeps then average? Also, what level of smoothing is most telling for these kinds of measurements? I've seen most other speaker plots use 1/6 octave. Thanks.
This positioning is what I found to be subjectively the best given the space. It's roughly the "Rule of Thirds" given here:
http://www.noaudiophile.com/speakercalc/
I want to try a few other placement options including off-axis response if I can.
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Hahaha! Nice....
Really quick since I'm at a work at a client site:
In this order:
- 1/6 to 1/12 octave for surgical correction of specific driver irregularities at higher frequencies. Will take measurement at 1m to driver.
- 1/3 to 1/6 octave for surgical correction of "prevailing" issues. By prevailing issues I mean from the overall room, baffle, or other effects which are constant regardless of microphone position. For example. I will put the mic at the listening position, move it a foot left, a foot right, in front, etc. If certain peaks or dips prevail regardless of mic position, then I will apply PEQ to it. Usually these types of peaks are narrow with a Q from 5-10.
- 1/3 to 1 octave for general overall sound balance.
I use RTA and pink noise for most measurements. The driver measurements - sweeps or MLS gated to avoid reflections past the mic distance. My general preference is a gentle 5-7db slope from 20-20k. Some advocate more such as a 10db slope. It depends upon the characteristics of the listening room. Less slope is needed for well padded / more diffuse rooms. More slope for more reverberant rooms.
Lots of fun. You'll learn a lot of nuances and really develop your ear for these kinds of things.
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Looks really good :)
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Looking good OJ!
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Wow, really nice.
Now I know you didn't do it, but could you let us know, theoretically if you were to do it, how you would go about it? Making those speakers, I mean.
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Round 1.
First of all, high SPL LF tones are a no-no with these speakers. Not that that's something I didn't already know. Driver Fs
is only 83 Hz. The surround deforms noticeably when I try to sweep from 20Hz. The response down there is nonexistent as you
would expect. And REW requires high SPL sweeps for some reason I don't know. Very scary, I lunged for the volume knob.
Everything I did is swept from 40Hz.
(http://i.imgur.com/J7OVbhx.jpg)
Not bad! I was expecting worse TBH. Log swept 512k from 40 to 20k. 1/6 smoothing applied. I daresay this looks even better
than Purrin's plot for the BK16 (unequalized, on page 3). But in the next measurements...
(http://i.imgur.com/Xl7ViEP.jpg)
WTF! What happened to my smooth-ish treble? (same smoothing here). Why do I have Grado mountains now? It took me a while to
figure this out. The original measurement was taken with the mic parallel to the floor. I had tilted the mic about 30
degrees upward so I could start taking measurements of my OS:MT. I felt eyeballing it midway would be the most fair
comparison. Like so.
(http://i.imgur.com/1OLfuF5.jpg)
I didn't expect it to change the BK12's plots so much though. Lesson learned, mic positioning will change HF response big
time. Now the question is, is the change from the sound hitting the mic at a different angle, or just from being moved 2"
upward? Or something else? I'm not sure. I'll try to parse that out when I start taking off-axis measurements. Current
theory is that this is just the driver being very directional and "beaming", although I would expect the HF response to be
lessened the more it moves off-axis.
FWIW, this last curve represents what I'm actually hearing the most. A nice midrange, a bit of brightness up top, and then a steep roll-off.
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Round 2
So, the OS:MT is a little speaker that I really like. I usually listen to it in the near-field and it sounds a lot different in a bigger space like this. Here's the plot according to Carmody and then my own comparison:
(http://www.parts-express.com/pedocs/tech-docs/300-706-parts-express-overnight-sensations-technical-document.jpg)
(http://i.imgur.com/ykPKxEh.png)
(http://i.imgur.com/trYEoRz.png)
It's amazing how different these speakers sound tonally. Just from listening to sine sweeps you can tell the tonal differences.
I don't have PEQ, but I do have tone controls. Here's that for each speaker.
(http://i.imgur.com/4dkQHBD.jpg)
(http://i.imgur.com/YLoal5o.jpg)
All of these plots match very well with my subjective impressions. The BK-12's horn couples with the floor to strengthen bass response big time. The OS's downward slope from 2k to 4k makes vocals seemed recessed. I find that the OS needs to be listened to on-axis in this space or else it loses focus. Carmody says that he voiced this loudspeaker with a subtle upper midrange and treble dip (for near-field listening) although it doesn't show up so much in the plots. My ears tell me it's definitely there. In a direct comparison, the BK12 can sound sibilant while the OS is never fatiguing but still has good presence.
So a question for you guys, do the bumps at ~125 and ~250 look to be room modes, or is it the horn resonances as was found in BK16? Because they're definitely there for the OS too. I think purrin mentioned comb filtering somewhere earlier in this thread, but I'm not sure how much that applies to this system. I'd like to do a cabinet simulation like Arnaud did to figure it out this cabinet's acoustic impedance characteristics.
Overall, the OS is more neutral tonally. I think it has more to do with its conventional design more than anything. Has really nice bass for such a small speaker and is totally non-fatiguing. If you want to compare it to a headphone, it's either the HD650 or LCD2 (without the veil). OTOH the BK12 is super fast and dynamic and articulate. There's something to be said for efficiency and what it gives "speed" as they say. On my 2220, I sat around 12oclock for 87dB of pink noise. For the OS, I was at full gain for 86dB. There's always the trade off between size/efficiency/bass response. The BK12 is probably best compared to a Grado that is tuned for extra bass. I hesitate to make that comparison because of the stigma and because it's not nearly as fatiguing as a Grado. I like it though.
Thanks for reading. Let's keep this thread going. :)p7
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So a question for you guys, do the bumps at ~125 and ~250 look to be room modes, or is it the horn resonances as was found in BK16? Because they're definitely there for the OS too. I think purrin mentioned comb filtering somewhere earlier in this thread, but I'm not sure how much that applies to this system.
The BK-12 measurements have peaks at 120Hz and 240Hz with a dip at 190Hz. The OS speakers have a similar response, but not as exaggerated. The dip is also lower at 175Hz. Probably a combination of the room or floor and effects of the horn or comb filtering. Try taking 1/12 octave measurements 1/2' from the horn and 1/2' from the driver if you are curious what it is. There's nothing more fun than trying to figure out what's going by gathering more and more data.
The output from the horn is going to be out of phase and also time delayed from the Fostex driver. That will do some funky stuff to the FR. It's a trade-off. We lose phase coherency and time alignment to get efficiency (bass response) leveraged from the back loaded horn.
One thing you may want to try are some stands to raise the BK-12s off the floor. Less bass @ 120Hz. The downside is that you may end up losing bass below that for something which doesn't go that low anyways. The fun part is integrating a sub. That's another can of worms and trade-offs, e.g. put a sub in the corner to increase efficiency, but excite room modes; or put the sub in more neutral place, but have it work harder. It's pretty easy to bottom modest subs with HT. IMO, subs require a dedicated subwoofer processor, i.e. EQ.
The smoothness of the smaller Fostex FE126? driver over the 6.5" FE166En in the BK-16 kit is expected. It's nice to know how smooth is it (I don't think I've ever seen a real life measurement.) The FE166En's have a few peaks / cone breakup in the upper mids / lower treble before rolling off, which is noticeable. The FE126 extends much further up to the mid-treble before cone breakup and roll-off. Of course the downside is that a strong signal below 40Hz will blow up the cone of the smaller driver. Again, it's all trade-offs.
My next project will be taking the drivers from the Moth Cicadas. Those are 8" drivers and sound even faster. It's strange, but in terms of "speed", 8" > 6.5" > 5". Go figure. Craig mentioned those are high Qts drivers where I can go sealed, which would be ideal for sub integration.
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@Tari
Maybe I'm not getting the cut of your jib, but here's the hybrid album of when I built the BK12 and the hi-fi rack. $50 of ply from Home Depot for the cabinet (and I had plenty extra). Madisound sells the pre-cut cabinet which is a better idea if you don't have the tools or experience to make the cuts yourself. You would just need to glue and screw. Here's the imgur album.
http://imgur.com/a/YuZaj
This was during winter break I think. And this is pre-Tung Oil + Gloss. The Tung Oil gives it a much richer tone that you see now.
@purrin
Yep, those horn measurements will be next. I did desk and nearfield measurements for the OS today. Also measured the OS's port output, which wasn't very fruitful. I'll try placing the mic closer next time or maybe measuring in an open space like JA does. Seeing as how this is the full-range horn club, I won't bother posting any more of the OS plots unless you guys want them.
I'm interested to see how you integrate the Cicadas into your system. They look to have some particularly bad treble nasties according to the Stereophile measurements. Are you going to try to go the purist route again and work 'em without a xover?
Also with regards to the measurements, REW help section mentions that LF measurements are best taken with the mic tilted vertically upwards. Why is this? Am I plotting even poorer bass response if it's horizontal? Thanks again.
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The rack is awesome!
- Try shoving the mic almost into the port of the OS. Make sure no obstructions (floor, walls, surfaces) are nearby.
- Continue with OS measurements. It's a good reference and comparison with the backloaded horn measurements.
- The Cicadas have severe treble peaks. I would still go no passive x-over / passive EQ circuits because that would defeat the point of a fast, highly power efficient speaker system. I would go digital PEQ to try to correct them.
- Because bass is omni-directional, pointing the mic up would place an emphasis on the bass measurement and "filter out" the mids / treble. Are you getting poorer response in the high bass? High bass is still somewhat directional and factors such as floor bounce might not be heard by the mic pointing upward. You just have to play with things and use your ears. 1/3 octave noise is a good tool too.
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One more thing. Fill spaces with sand if you haven't done so.
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Whoops, forgot about the sand. She's sealed so no going back. But now that I don't have the wimpy dowels in place the cabinet is much less resonant. Knuckle rap test tells me it's fairly solid at least, and I don't hear any overt cabinet resonances but I need to do more listening. Tapping the side of the mouth still produces a hollow sound, but I'm guessing that not abnormal. I have 2 sets of isolation spikes that I might try to fit on at some later point. I also need to try to build those stands and see if they change the sound. I know you recommend lifting them, but I feel like the BK12 needs all the floor coupling it can get. I imagine the FE166 driver itself has decent midbass response. The FE126 has none.
These speakers seem to defy conventional logic when it comes to the bass being omnidirectional. It's definitely not. Usually when you take a few steps off-axis, it feels like the tweeter got turned off. With these, it feels like the bass and treble go away. So I guess these have a more uniform off-axis roll-off than you traditional 2-way. But the treble's off-axis response doesn't look too great I'll wager.
I'm going to find my old man's camera stand and see if I can mount the mic on that effectively. That'll give me adjustable height too. I think my near-field measurements (with a single speaker) are a little skewed because I just placed the mic on the other cabinet. The surface could have caused some problems. My near-field (at my desk) measurements of the OS were very interesting though. I'll post those sometime tomorrow. I would like to try measuring outside, but tomorrow is Saturday and I don't want to piss off any neighbors. That'll have to wait for Monday.
What exactly should I be listening for with the 1/3 octave noise? I was trying log swept tones with the OS to see if I could point out where the port shuffling was happening at high SPLs. It seemed to be happening all the way up to 100Hz actually. Then I tried listening for the room modes (or horn modes?) between 100 and 300. I was able to identify the peaks but trying to find the dips was a lot harder. As in, they didn't sound like reductions in SPL just general weirdness at that area (~175Hz). I need to try this with the BK12 and measure the mouth up close and see what happens.
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Great job OJneg, can still fill, drill and plug with a birch dowel, use a face grain plug if you were particular about it.
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Here's the desktop setup. Mic is placed approximately where my head would be when listening. Parallel with ground. 2' from each baffle. This is slightly above the tweeter's vertical axis, but *way* off-axis horizontally. Note the tweeters are firing past the the mic; I'm not doing the classic equilateral triangle here. Why not? Toeing in directly removes the perception of depth and soundstage I find. They *can* be toed in directly without seeming to bright (Carmody accounted for this in his design), but this configuration seems best to me.
(http://i.imgur.com/lGOb2TC.jpg)
(http://i.imgur.com/VLfz03B.png)
Red is desk, blue is living room. Not level matched obviously.
Bass is way too boomy as you can see, although this is to be expected when the rear port is <6" from the wall. Subjectively, this is just as bad as it looks. It's the first thing you notice when sitting down to listen. Makes me wish I had built a design with a front port like the Zaph ZA5.2. The null at 170 seems to be mostly gone though, telling me this was probably a living room interaction. I'm also noting that the peak at 250 isn't here anymore, although the one at 120 still is. I think I can surmise that 120 peak has to do with the port specifically, which is why this back wall is aggravating it here to an even higher degree.
Now..the null at ~350. I'm thinking this is a cabinet resonance. Playing chromatic scale (at high SPL) lets me hear a very annoying vibrational resonance going on here. I don't think this is my port vibrating or shuffling though, that seems to happen down lower. I'm not sure if this is a construction fault on my part or just the nature of the beast. I've never noticed it with music though, but again, I listen near-field at fairly soft levels. I'll have to figure this out later.
Treble roll off is even more exaggerated in this positioning, as is expected when you're this far off-axis. But note the resonances at 1k and 2k here. More on this next.
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Get a proper / taller triprod, or move thing more forward on the platform. That surface could affect the measurements - wondering about some of those dips. Also, can you mount the mic want a little bit more forward?
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So, a buddy of mine told me I should take near-field measurements of a single speaker to get a better look at what's going on with the driver's response. He recommended I take the measurements in the center of the room elevated off the ground by at least 30", with the mic 1m away. Here's that.
(http://i.imgur.com/XkHq5P7.jpg)
(http://i.imgur.com/dx14dB7.png)
Ok, so obviously the 120 peak is gone now that I'm far enough away from the wall, although my 170 null is back (because of the living room?). But other than that, this speaker is fairly flat and well extended. Except for some problems with the upper-midrange. I originally thought this was cone breakup. Metal cone woofers are supposed to have major problems with cone break up. But it wouldn't make sense to have the whole region around 1-2k elevated. OTOH, the peak at 4k (which is also the xover point) looks exactly what I expected the cone breakup to be. It sounds like it too. Nastiness there when I play chromatic scale.
So what's going on in the presence region? I don't know. I originally though the 1k, 2k, 4k might be the triple octave penetrator that has been spotted in headphones. But I'm not hearing it. I've commented before that the OS seems recessed in this region more than anything. Here's Carmody's own commentary FWIW:
The actual woofer filter is 2nd order electrical, with the addition of a small capacitor across the inductor, which acts as a notch filter (these are sometimes referred to as "tank" or "elliptic" filters). The tweeter filter is 3rd order electrical, with an L-pad used to attenuate the tweeter's level. The crossover point occurs around 4,000 Hz. Although it's not apparent on the frequency response graph, I intentionally voiced the Overnight Sensations with a subtle dip in the midrange. I did this for two reasons. One, to ensure that the speakers would be listenable for hours and hours without becoming fatiguing . Two I wanted them to be forgiving of recordings that were "less than top-notch" (of which I have many).
It might be the tweeter's output is combining with the woofer in this region, which is why we're seeing it elevated.
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With the nearfield measurement, align + level mic directly straight on to tweeter. No angles.
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Bass is way too boomy as you can see, although this is to be expected when the rear port is <6" from the wall. Subjectively, this is just as bad as it looks. It's the first thing you notice when sitting down to listen. Makes me wish I had built a design with a front port like the Zaph ZA5.2. The null at 170 seems to be mostly gone though, telling me this was probably a living room interaction. I'm also noting that the peak at 250 isn't here anymore, although the one at 120 still is. I think I can surmise that 120 peak has to do with the port specifically, which is why this back wall is aggravating it here to an even higher degree.
Can you use port plugs? How much of the <100Hz response is the port as opposed to the driver itself?
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Good idea. I'm not sure how much output the port is delivering there. Woofer Fs is 66 Hz, and the port is tuned to the 57 Hz with a -3dB point at 50 Hz. So it's not like the driver isn't capable of 100Hz. Again, I'm not sure.
I'm guessing I could plug the port just by sticking in a towel, yes? It might screw up the rest of the bass response though. I'll probably lose the majority of my response below 100 Hz. I'll try and see how it sounds and plots.
(http://i.imgur.com/ELYMmLq.jpg)
(http://i.imgur.com/JkGGkNX.png)
Again, this is fairly flat. Note the Y-axis. But like I said, the 5dB boost in the presence region is not there to my ears. My buddy saw the near field response and provided a PEQ profile to try to fix it. First impressions are that it veils the vocals even further and I don't like it. Obviously I need to spend more time trying it out.
My current theory is that the elevated area around 1k-3k is the woofer's output combining with the tweeter's. But since I listen off-axis, the majority of the woofer's output is "beaming" and not seeming too bad to my own ears. Or the elevation here is caused by some crossover phase issues. Or I just prefer colored sound for whatever reason.
I'm still going to try to deliver THD and off-axis. More to come today. To the garage!
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Maybe try cutting some foam to fit. Pipe insulators would also probably work, and they would allow you to experiment with reducing the size of the port rather than sealing it entirely.
(http://forum.ascendacoustics.com/images/ascenduploads/qp_all.jpg)
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Usually, you don't want to apply PEQ based on the nearfield response taken outdoors, unless of course you actually hear the speakers under those circumstances. The nearfield response is good for identifying issues with the driver or crossover. It doesn't look like there is anything serious. (I do note among the various measurements a narrow depression at 3.5k.) The nearfield FR with its broad peak around 2k, looks like it would be perfect sitting on a table with some reinforcement from a back wall. I would expect everything 1k and below to be bumped up a bit.
As for the mid-bass hump, the speakers in that photo could be too close to the wall. Trying moving them out so there's about 12". I suspect the mid-bass boost is intentional. Many bookshelf speakers are designed with a mid-bass boost to make up for lack of low and sub bass.
Take a listening position measurement (sweep or RTA) with both speakers playing. This is going to be the one that counts the most.
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I agree with you purrin. But the other guy I'm talking with is kind of a nut for near-field measurements for some reason. The PEQ he suggested clearly isn't working for me at my listening position. Maybe if I listened on-axis it would. My next step will be seeing if I can improve the response at my desk since that's where I usually listen to these. That includes trying to play around with some foam in the port to cure the boominess. But until then, here's what I did today.
(http://i.imgur.com/GBJ0JOk.png)
Surmise to say distortion was very high in the bass. No surprise to me. THD is 11% at -20dB and 23% at -10dB
(http://i.imgur.com/i2El1f3.png)
3% -> 7%
(http://i.imgur.com/PsLIsMw.png)
.1% -> 1%
(http://i.imgur.com/cWbthbU.png)
.2% -> .5%
(http://i.imgur.com/3tjpEai.png)
.5% -> .6%
I read up on the RTA FFT parameters and I feel that these settings got me the most resolution and usefulness, but I'm not sure how to interpret loudspeaker distortion in a practical sense. I have questions.
- Where does distortion in loudspeakers stem from in the first place? I understand how certain acoustic devices like horns and diaphragms can have natural harmonics related to their size and specs, but why do we see distortion over a broader band of frequencies?
- So how accurate is this type of test anyway? What's all the stuff that looks to not be harmonically related to the signal but is clearly not the noise floor? Would it be fair to say these loudspeakers are dominated by 3rd order distortion more than any others?
- How useful are these for figuring out how the speakers sound? I've heard some guys like Zaph say that he voices his speakers with a downward tilt because distortion components make them sound brighter. Similarly, if I'm playing pink noise and set my eyes on flat, won't I actually have a warmer tilt if the distortion components are summing with my input signal an octave above?
- What does rising distortion tell me, as opposed to when distortion remains relatively constant with SPL?
- Does anyone ever try to EQ to correct for distortion or is that just total stupidity?
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I agree with you purrin. But the other guy I'm talking with is kind of a nut for near-field measurements for some reason. The PEQ he suggested clearly isn't working for me at my listening position.
A lot of speaker builder guys like to use the nearfield measurement because it's the most easily replicated "standard" from one person to the next. (Its' not reasonable to replicate individual listening environments.) It's also somewhat of a "standard" used by JA @ Stereophile. This measurement actually works well if everyone puts their speakers at least several feet from the back and side walls, and has a good deal of room between the listening position and the wall behind them.
Listening position measurement is best, but for obvious reasons not always possible. Studios (and custom installations) will try to aim for a slight downward slope from 20Hz to 20kHz. 10db is often quoted. I've used anywhere from a 5 to 10db slope depending upon intended purpose and room parameters.
The good speaker designer designs for an expected case use (against walls, away from walls, etc.) and documents this. Personally, I feel all top-end speakers should have baffle-step compensation adjustments like the fancier pro-monitors.
- Where does distortion in loudspeakers stem from in the first place? I understand how certain acoustic devices like horns and diaphragms can have natural harmonics related to their size and specs, but why do we see distortion over a broader band of frequencies?
- So how accurate is this type of test anyway? What's all the stuff that looks to not be harmonically related to the signal but is clearly not the noise floor? Would it be fair to say these loudspeakers are dominated by 3rd order distortion more than any others?
Most speakers are dominated by 2nd order distortion. The HiVi woofer you have could a bit funky with its design.- How useful are these for figuring out how the speakers sound? I've heard some guys like Zaph say that he voices his speakers with a downward tilt because distortion components make them sound brighter. Similarly, if I'm playing pink noise and set my eyes on flat, won't I actually have a warmer tilt if the distortion components are summing with my input signal an octave above?
One can always say that distortion components can make something sound warm, especially with drivers which produce higher bass distortion in proportion to mid/treble distortion. At reasonable volumes, the distortion products will be too low to influence an RTA measurement. Besides, the distortion products will likely be be wide band. I don't think about stuff like this too much. You start to miss the forest for the trees.- What does rising distortion tell me, as opposed to when distortion remains relatively constant with SPL?
Rising distortion with increasing SPL is normal. Distortion that tends to not change with SPL probably means the driver is performing better at louder volumes where the distortion as a percentage of the fundamental is lower.- Does anyone ever try to EQ to correct for distortion or is that just total stupidity?
You can use EQ to correct for linear distortion (FR), but you cannot use EQ to correct for non-linear distortion.
I'm not big into non-linear distortion so long as it's sufficiently low. (Although small driver attempting to play bass = bad / distortion.) The masking effect will hide the audibility of most distortion.
I'm more of a stored energy / CSD guy for regular listening. The distortion stuff gets critical for high SPL pro applications though.
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I was a sad panda for a while there. I was trying to unscrew my port and I dislocated the two pieces of it. I was getting a real nasty vibration whenever I played LF tones (or music for that matter). Had to cut open the baffle and glue the port back together. All good now.
Here's off axis measurements. I kept the mic in the same position and used a right angle to orient the speaker at each angle:
(http://i.imgur.com/RX9hKmY.jpg])
(http://i.imgur.com/IJgmux5.png)
(http://i.imgur.com/kaqdfYr.png)
So yeah, off-axis response is pretty wacky for the BK12. OSMT is very nice in comparison.
Instead of putting the BK12's THD by itself, I'm going to compare it to the OSMT. I think these plots are fairly useful in figuring out how each of these speakers sound actually. The OSMT's own inefficiency is working against it in this case, as it needs a lot more power to reach the same SPL as the BK12 for these measurements (Even though the fundamentals are not perfectly matched in any of these). Let's see. Note that the colors switch, sorry.
(http://i.imgur.com/6dptWSg.png)
(http://i.imgur.com/koWFZXv.png)
(http://i.imgur.com/XbQstkb.png)
(http://i.imgur.com/pZnxNIi.png)
So even though the BK12 fails in treble smoothness and off-axis, it absolutely kicks the OSMT's ass in distortion. Especially where it counts, the midrange. As the fundamental goes up, the OSMT looks slightly better in comparison. It's interesting to note:
- The BK12 switches from a dominant 3rd harmonic to a dominant 2nd and non-existent 3rd from 100Hz -> 440Hz. ?
- The OSMT is absolutely littered with higher-order components and hash. And I think the metal cone is the culprit here. Are metal cones the balanced armatures of the loudspeaker world?
Also here's the BK12 near-field from different positions, as well as the horn output.
(http://i.imgur.com/o7tEUsE.png)
(http://i.imgur.com/v6cdzHw.png)
(http://i.imgur.com/XGiOK7N.png)
- Notice how smooth the 1in and 2in measurements are. And note how this is only 1/24 smoothing. Even without smoothing it looks good. From 3ft away it's not nearly as clean. Why is this so? Is this just some sort of measurement artifact, or is there something that messes up the curves the farther you go away?
- I'm not sure what to really glean from the the horn output plots. Might be seeing the horn peaks that are evenly spaced here? Not sure.
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Posting this fe166 / BK-16 graph for reference. 24" from driver. 1/24 octave (basically no smoothing.)
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Gated CSD 3.02ms at 24" from driver.
Fe166 Stock.
No Smoothing.
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Here's the group delay of the driver in the bk-16 enclosure with the mic level to the cone at 24" away.
As we can see, the bass below 300 Hz is delayed a bit by up to 10ms.
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I'm going to try both of these with the BK12.
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Are you sure you're not measuring your room's CSD there? Looks way too terrible for a driver.
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AS: A room CSD would have much more energy time wise, no? More like 300ms rather than 3ms.
I'm not getting the same "ringing" at my breakup nodes like you are. My 7k peak seems to decay equally with the rest of the treble. But REW generates waterfall plots from swept tones. Are you using an actual impulse (time-domain) to get your waterfalls?
I am finding some interesting things with regards to group delay though. The full-range drivers seem to be very much minimum phase from 1k and up. But by generating a minimum phase (with respect to amplitude response) and finding the "excess" phase, I get to see where my group delay is. Sure enough, it seems to be caused by the horn dicking around in the midrange.
OSMT
(http://i.imgur.com/eWmqGKe.png)
BK12
(http://i.imgur.com/2v3ST44.png)
EDIT: How much space does the out of phase signal from the horn need to travel in order to combine in phase? If I try to take the same plots with the mic farther away, would I see less group delay? Or just better frequency response in the upper bass?
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The fe166 CSD is 100% consistent with the near-field FR measurement. This is what I love about speaker driver measurements vs. headphone measurements. CSDs really aren't necessarily. A 6" driver is going to have issues in the treble no matter what.
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Latest EQ at listening position. I sort of went AstralStorm EQ bonkers on this. Actually, not that much. The dip at 78Hz is one of those annoying uncorrectable room effects. I left the treble after 5k completely alone. Because of the directional nature of the drivers used, the slope is less steep than I would usually have it.
I'm done with this project and very pleased with the results. Moving on to the next one when I have more time to spare.
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Fostex raise their prices with effect on orders from October http://www.fostex.jp/attach_files/0000/0263/FOSTEX_kaitei_Release.pdf price increases of up to 20% there about.
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Hopefully it's an intra-Japan price raise. If US prices stay the same, there's still an effect price increase since Japan is doing it's own quantitative easing right now with substantial effects on the value on the Yen.
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I hope thats the case, this increase would match against the decrease in Yen value indeed.
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I love when things I own become discontinued or unobtainium! Always seems to make them sound better.
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Fostex raise their prices with effect on orders from October http://www.fostex.jp/attach_files/0000/0263/FOSTEX_kaitei_Release.pdf price increases of up to 20% there about.
Scared me for a second, have been waiting to pull the trigger on a pair of T500's. Rep at Madisound has not heard anything yet, guess I should just be safe.
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Just wondering, how well do couches work as bass traps? Assuming it is against a wall of course.
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If any cs member is looking for a pair of T90a's let me know before ebay ( :)p10$), after listening to the t500's I could not resist.
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I'm new here and just subscribed to see the pictures on this thread. Thanks to Marvey for your excellent write up - it is the best I've found on the BK-16.
In the next few months I'll be building a variant, the BK-161 which originally was designed for the FE168 Sigma but most often the FP163 was put into it. (similar to the BK-10 and BK-101 variants).
There is a German website (no affiliation with it, just an interest) that describes another form of a horn, basically a bass reflex with the port being a short horn. It goes lower in frequency and the horn is supposed only to work on the frequencies below the cutoff of the BR part. According to reports it works and it uses a shorter horn plus it uses drivers that are having a Qts of around 0.4 ~ 0.5.
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I just got the Sigmas in the BK-16 box. Not designed for it, but I made it work. More details later. The Sigmas are really really nice.
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The follow up. Yeah I understand - it was so hard for me to find reliable information on the BK-16 kit of even on the FE168EZ Sigmas.
If there's one single thing I would say, I think the FE166 and especially the FE168 Sigma driver perform better if roll them off a little bit on the bass with a 200-270uF cap and fill in the bass with a good 12" or bigger driver. Depends on your priorities and the demands of your recordings though.
http://www.changstar.com/index.php/topic,1680.msg44748.html#msg44748
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.......
The EnABL stuff definitely smells like voodoo. I would like to see measurements.
The "pre treatment" (or "trifoil" pattern with damar and subsequent mod-podge coating) for the FE127e was indicated by another party's testing. Subsequent measurements proved that the 7 ~ 8 Khz peak has all but completely disappeared. (that peak can be triggered by half the frequency). Have searched high and low and have not come accross any measurements for the "enabling" part and as I understand form the postings it is all based on listening tests and "subjective opinions".
Be aware that the Fostex drivers need considerable time to "loosen up", some will connect them out of phase and place them face to face with a blanket over them and let them play for a week or two before listening. No bass to be expected with less than 25 hours on them at "normal" levels. Horns are also subject to "aging"- the timber needs to acclimatise after the cabinet is constructed, have seen Japanese test results after a day, a week, two weeks and a month and the response curve clearly showed the changes.
Due to the high sensitivity the normal input required is pretty low so do not place a big amplifier in front of it, that 150 watt per channel solid state amplifier is not going to sound nice. (as you already discovered). Best is a single ended tube amplifier since you won't have crossover distortion.
Edit: Just be aware that with most SE amplifiers any type of passive filtering will increase distortion.
Regarding REW and high levels: on my computer there is a setting to increase the sensitivity of the microphone (like switching on a preamplifier) - afterwards the testing could be done with my Samson USB Go-Mic at pretty low levels (before that I was afraid of destroying the driver).
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Yeah, I noticed the Fostex drivers needed a small amount of break-in. (The Seas drivers with rubber surrounds never seemed to require break-out.) I assume the treated paper or foam surrounds the spider of the Fostex's needed to loosen up. The material seems kind of crusty when new from the box. Loosing them up probably ends up increasing Qts and lowering Fs. I won't bother placing them face to face and playing them out of phase to break them in faster since it eventually happens. There's no rush on my part since I'll keep tuning things for at least a few weeks before I am totally happy.
And oh yes, the shellac, varnish, etc. on the cone WILL work. That's certainly not BS. I've tried that before on various cheap paper cones. That's changing the resonant properties and mass of the cone.
I plan on doing a comparison between the EnABL dots and scribbling "Admiral Akbar is Great" in cursive script around the cone to see which method is better from a subjective point of view.
For those of you reading this post who are unfamiliar with EnABL, read here: http://www.planet10-hifi.com/fostex.html (http://www.planet10-hifi.com/fostex.html)
Single-driver guys tend to be a superstitious lot. I can't wait to scribble "Admiral Akbar is Great" in cursive script around the cone.
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There is a difference between having with laser detect certain resonance areas in the cone (like the FE127e / FE126e and addressing those with damar) and the voodoo of painting little dots everywhere. I've got a hard time staying open minded and believing the latter.
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I'm finding the FE166 to be tonally more laid back (than the FE126) but its presentation is more forward and coherent at the same time. I hope that makes sense. Also more open sounding. A definite upgrade on my baffle. :)p1
I'm able to cross the FE166 much lower and not worry about blowing it out with bass. First order crossover at 180Hz ATM. Fs of the FE126 was around 82Hz so it tended to boom, whereas the FE166 has Fs at 53Hz so it lets the filter be much more effective.
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I don't know if anyone still follows this topic...
I recently purchased the BK-16 kit and an Elekit TU-8200DX tube amp, and found this thread. I'm really enjoying this combo, and reading this thread from the first page.
(http://IMG_20150111_184715_132.jpg)
Here is a link to a few Nagaoka designs from a Japanese web site. http://homepage3.nifty.com/spida/eng-page9-1-5.htm http://homepage3.nifty.com/spida/eng-page25-6.htm
If you scroll down to the D-3MKII.1 enclosure for a F208e Sigma, you will notice Madisound almost exaclty copied this design for their BK series.
Nagaoka-San is now deceased, but his designs are some what legendary. Having several published books in Japan, with his designs.
Here is another link to the homepage of the same fellow that posted the above D-3MKII.1 enclosure. http://homepage3.nifty.com/spida/framepageeng-9.htm enjoy browsing! some really interestinfg stuff!
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There was another Japanese site that also provided RL horn designs for the Fostex. They used layers of wood machined with a a horn curve stacked together. Can't seem to find it.
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There was another Japanese site that also provided RL horn designs for the Fostex. They used layers of wood machined with a a horn curve stacked together. Can't seem to find it.
http://telavox.web.fc2.com/speaker_box3.html#mmt
http://telavox.web.fc2.com/assembling.html
A little bit pricey, even more so with the special acoustic dampening coating...
These folded horn designs really fascinate me! One of my FE166En have a large crease on the front suspension, and the other has a somewhat smaller one. Don't know how much it affects the sound... Madisound said they would ship a replacement tomorrow, but I asked if I could pay the difference and upgrade to the Sigma, still waiting on their response.
UPDATE: Madisound will let me pay the difference and upgrade to the Sigma's, but they are backordered and a couple weeks out. My hat's off to Madisound for their quick resolution and flexibility.
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The follow up. Yeah I understand - it was so hard for me to find reliable information on the BK-16 kit of even on the FE168EZ Sigmas.
If there's one single thing I would say, I think the FE166 and especially the FE168 Sigma driver perform better if roll them off a little bit on the bass with a 200-270uF cap and fill in the bass with a good 12" or bigger driver. Depends on your priorities and the demands of your recordings though.
http://www.changstar.com/index.php/topic,1680.msg44748.html#msg44748
What brand and what voltage cap did you use?
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Radioshack 'lytic or whatever parts I had on hand. I tired bypassing the Radioshack parts with small sized boutique caps, but I didn't like the sound. Eventually I went back to getting rid of the caps and let the play full range with the Rag. With tube amps, I preferred the caps in.
I'm a really bad person to ask about caps. Yes, they make a difference, but I don't have the time and would rather spend the time trying out different designs.
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Radioshack 'lytic or whatever parts I had on hand. I tired bypassing the Radioshack parts with small sized boutique caps, but I didn't like the sound. Eventually I went back to getting rid of the caps and let the play full range with the Rag. With tube amps, I preferred the caps in.
I'm a really bad person to ask about caps. Yes, they make a difference, but I don't have the time and would rather spend the time trying out different designs.
Thanks, just curious because the price on some audiophile caps are fairly steep.
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That's exactly why I don't want to go there. The end result is OCD where trees are taken for the forest and caps costing more than the drivers.
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I feel the Jantzen crosscaps are a respectable step up from cheap electrolytics. At the moment I'm using a 4.7u Crosscap in parallel with a 15u non-polarized 'lytic in front of my 4ohm waveguide AMTs. I'll probably move up to a Jantzen Supremes or Silvers eventually once I settle down on the tweaking.
BTW, I still think the FE166En is excellent sounding.
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Got the FE168Ez's installed in the BK-16 enclosure, and I'm really liking what I'm hearing! Definitely a step or two up from the FE166En's.
I don't feel the need for a tweeter anymore either...
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Nice. That was my experience too, made the tweeters not so necessary.