CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => Speakers => Topic started by: Marvey on December 03, 2014, 09:56:07 PM
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Since the Rag turned out better than I thought, I have decided to build a floor standing speaker to make the most of what it (and the Gen V) can do. Came up with a simple list of requirements:
- Must be cheap relatively speaking. The prototype must be as shitty looking as possible.
- Open baffle bass. Based on prior experiments, OB seems to reduce the amplitude of room nodes by 50%. OB should be helpful for those annoying dips which are impossible to correct without multiple subs. Quality bass without room interactions is something most headphone people take for granted.
- Decent frequency response. Don't want to have to depend upon digital EQ, so I can use turntables and CD transports.
- Simple crossover circuits. Goes with cheap. Complex crossover / EQ circuits can result in excellent frequency response, but at too huge of a cost to reduced dynamics and microdetail. Been there. Done that.
- Bi-amping with dedicated amp for OB woofers, possibly with line level passive crossover and bass roll-off compensation.
- Moderately to highly efficient at 90db+ Less of a priority since Rag is being used. But efficiency is never a bad thing. Efficient drivers tend to sound more lively too.
- Three way or more. More drivers playing within their operating areas should result in less intermodulation distortion. Not a huge priority though.
- Use of drivers which are readily available. No more unobtainable stuff like Moth Cicada drivers.
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Idea #1
Keep Eminence Beta 15" woofer from old project. Alpha has higher Qts at > 1.0 which will have much better bass extension in an OB. However that high of a Qts may be too uncontrolled for my taste. The Beta 15" with Qts ~0.50 will have to do despite less bass extension. I don't remember the Betas producing anything significant below 45Hz. Might need a sub to fill in up to 45. Oh well. IMO, OB benefits > downsides. The Acoustic Elegance 15" drivers look nice, but again, want to keep this project cheap.
Mark Audio Alpair 12P (8" driver) and Alpair 7P (4" driver). Paper drivers from Mark Audio. Realistically probably about 90db efficient. $135 + $79 respectively. Using the 8" wide-bander alone might be asking too much and the driver may be too beamy. Hoping the 4" will help a little bit in smoother high-end extension and vertical dispersion. Same cone material and similar construction should result in a more cohesive sound.
Concerns:
- How much more effective would the 4" would be in terms of dispersion width or treble performance? I haven't measured these drivers myself. I haven't see off-axis measurements.
- Use of first order crossovers will result in combing and funky vertical off-axis response.
- Imaging diffuseness.
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Idea #2
- Similar to above with same OB bass driver but with following changes on mid/treble:
- MTM arrangement with 2 x 6" Alpair 6P paper drivers which are around ~90db efficient. Choosing to double up the 6" for better efficiency and less excursion. Also hoping the 6" can extend better than the 8" before handing off to the tweeter.
- In between the woofers would be sandwiched a HiVi RT2C isodynamic planar tweeter. A RAAL with the amorphous core would be nice, but again we are talking cheap. The 70-20 RAALs which can take more punishment are not available to the general public. And any smaller RAAL will likely blow without a complex crossover. In any event, I'm letting the 6" do most of the work and letting the RT2C act as a semi-super tweeter.
- The faceplate HiVi RT2C of the tweeter will assure good horizontal dispersion and limit vertical dispersion, which in this case would be a good thing to prevent comb filtering effects. Thinking about trying something borderline like crossing over at 6kHz first order. If that doesn't work, maybe a wide notch circuit somewhere below the crossover point. At $80 a piece, they are relatively cheap and can be experimented upon.
- Finally, the RT2C isn't a dipole (at least I don't believe so), so maybe this setup might image better withoutsome of the higher frequency backwave hitting the back wall and causing too much of a diffuse stereo image.
CONCERNS:
- Questions about HiVi RT2C power handling with first order crossovers
- Cohesiveness between the HiVi (iso planar) and Alpair 6" (paper cone)
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are you co-locating the woofers with the rest of the drivers? so 2 woofers total probably?
Idea #1: I mean, Qts of ~.5 is probably okay, but that number is taken in a vacuum. What's system Q in this case, .7? I'm guessing open baffle low-Q of .2, right? I'd try to go for woofers with Qts ~.8 if you can and forego the separate subwoofer(s).
Edit: Idea #2: see if you can get the 64-10 OEM somewhere. Reach out to Dennis Murphy or Jim Salk offline and see if either will sell you a pair of 70-20s or 64-10s they've taken as returns or something like that.
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In the spirit of making this cheap and looking as horrible as possible, a simple scaffold or frame for the drivers will be first constructed. Cutout cardboard from moving boxes will then be mounted onto the frame be used as the baffle. This will allow for easy experimentation of baffle widths and shapes.
After baffles are finalized, polycarbonate or aluminum baffles can be machined so my wife does not kill me.
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are you co-locating the woofers with the rest of the drivers? so 2 woofers total probably?
Idea #1: I mean, Qts of ~.5 is probably okay, but that number is taken in a vacuum. What's system Q in this case, .7? I'm guessing open baffle low-Q of .2, right? I'd try to go for woofers with Qts ~.8 if you can and forego the separate subwoofer(s).
These would be ideal: http://www.aespeakers.com/drivers.php?driver_id=47 (http://www.aespeakers.com/drivers.php?driver_id=47)
0.82 Qts $339 each. More xmax than the cheap Eminence. Also magnet strength probably more even throughout the excursion range of the voice coil. Might be a good idea just to bite the bullet and save on PLLXO design. There is something charming (in the sense of fuck you high-end) with $75 15" Eminence drivers though. I don't think I even had to use compensation in the room to get down to 45Hz.
For idea #2, still looking for 6" driver alternatives. Must be a real ~90db sensitive though.
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Have you considered doing a full mirror of the drivers? I don't think I've ever seen this done in a fully open baffle configuration.
(http://nerds.dk/files/HighPerformanceAudioMontanaMasterReferenceMidt.jpg)
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I own a pair of Dunlavy speakers that use that array. They are my favorite. They are sealed so in a larger room I have trouble getting enough bass. Flat response, just not enough bass energy for a big open room. Sounds like a Quad that goes down to 20 Hz, just doesn't rattle the china. Have thought about doubles subs at some point. Like when I win the lottery!
I think it is a variation of a D,Appolito array. Crossovers where 1st order. Put a lot a stress on the tweeter, so he had to spend time trying several until he found one that could handle it.
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Dynaudio also uses it in their Confidence and Evidence lines, which are far superior to everything else they make.
(http://www.stereophile.com/images/archivesart/Dynconfpic1.jpg)
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I just really like the sound of this array, done right. The best of the Quad sound, with bass that goes low. And they can rock when need be. :)p7
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Hate to be the debbie downer in this thread but I think I'm going to start moving away from my OB project. It's just not there for me anymore. I'm going back to the sound of my 2-way mini-monitors and they seem to regularly wow me with their capabilities. Despite the fact that they're cheap as hell. My next project will probably be a 2-way monitor-type speaker in a medium sized enclosure that I can place strategically on stands. With an emphasis on high quality drive units (thinking ScanSpeak) and a tweeter that reliably performs on a smaller baffle. This design looks very enticing for me ATM but I'll need to look at more options:
http://www.troelsgravesen.dk/DiscoveryW18.htm
As far as I'm concerned my project and its components are Changstar property. Marv, next time we meet up I'll hand off the waveguide AMT's; I think you'll like them. You can also have the 15A's for research purposes. Or if someone else wants them to build some crazy subwoofers let me know
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There's definitely a reason why the humble two-way has been around so long pretty much unchanged in basic concept. The stepped baffle idea is an interesting one, provided that the diffraction and reflection issues can be dealt with as mentioned in the article. A waveguide would avoid those issues and still allow for time alignment, but it's REALLY easy to mess that up and end up with a fire spitting mess.
I wonder why not just opt for a sloped baffle ala Reference 3A?
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been thinking on this for a long time.
Go with the cheaper woofers. Worst case you add fancy standalone woofers and cross over somewhere between 45 and 60Hz. Two fast, powerful 15s or 18s filling in the bottom end with plenty of juice from an ep4000 or something similar will be AWESOME and you don't have to commit to getting them until you spend time with your finished build.
The spirit of the project is to middle finger speakers on the market with something epic and affordable. I think you should keep to this as much as possible (no $340 woofers for now).
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Hate to be the debbie downer in this thread but I think I'm going to start moving away from my OB project. It's just not there for me anymore. I'm going back to the sound of my 2-way mini-monitors and they seem to regularly wow me with their capabilities. Despite the fact that they're cheap as hell. My next project will probably be a 2-way monitor-type speaker in a medium sized enclosure that I can place strategically on stands. With an emphasis on high quality drive units (thinking ScanSpeak) and a tweeter that reliably performs on a smaller baffle. This design looks very enticing for me ATM but I'll need to look at more options:
http://www.troelsgravesen.dk/DiscoveryW18.htm
As far as I'm concerned my project and its components are Changstar property. Marv, next time we meet up I'll hand off the waveguide AMT's; I think you'll like them. You can also have the 15A's for research purposes. Or if someone else wants them to build some crazy subwoofers let me know
I have really really really nice silk dome tweeters for you.
The best of the classic tweeters. you can cross down low 2kHz with 2nd order.
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I have really really really nice silk dome tweeters for you.
The best of the classic tweeters. you can cross down low 2kHz with 2nd order.
That would be perfect
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This is what I have for you: http://www.scan-speak.dk/datasheet/pdf/d2905-990000.pdf (http://www.scan-speak.dk/datasheet/pdf/d2905-990000.pdf)
Measures better in RL than on their spec-page.
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Have you tried Audio-Nirvana full-range speakers?
I have not heard myself but they have interesting new "classic" line. It seems there is coming 12" Classic FR also.
Money back guaranteed, sounds good to me. And the price is right.
I would try those, but shipping to Europe+customs is too much just to find out...
Just thinking that good full-range could improve even more the spaciousness, 3-dimensionality, because the sound is coming from one "spot".
With 2-ways, 3-ways, 4-ways etc. comes the crossover problems if they are not designed well, and still they have problems.
The loudspeakers building is maybe the hobby what i enjoy the most, i think it is the "link in the chain" where is easiest to make the system sound better...or worse ;)
I have build Troels, Tony Gee, GR-Research, Strassacker, Hifitalo, and some other designs but my favourite speaker-genius guy is Wayne Parham from Pispeakers. Build the 4Pi or some corner horns and i think you have speakers for long time :)p1
Regards,
na
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Have you tried Audio-Nirvana full-range speakers?
I have not heard myself but they have interesting new "classic" line. It seems there is coming 12" Classic FR also.
Money back guaranteed, sounds good to me. And the price is right.
I would try those, but shipping to Europe+customs is too much just to find out...
Just thinking that good full-range could improve even more the spaciousness, 3-dimensionality, because the sound is coming from one "spot".
With 2-ways, 3-ways, 4-ways etc. comes the crossover problems if they are not designed well, and still they have problems.
The loudspeakers building is maybe the hobby what i enjoy the most, i think it is the "link in the chain" where is easiest to make the system sound better...or worse ;)
I have build Troels, Tony Gee, GR-Research, Strassacker, Hifitalo, and some other designs but my favourite speaker-genius guy is Wayne Parham from Pispeakers. Build the 4Pi or some corner horns and i think you have speakers for long time :)p1
Regards,
na
The pi's sound interesting. I have some old Altec compression horns sitting around that I want to do something with. Will take a different approach and not corner load. I don't see myself not doing open-baffle bass. Bass in boxes seems to problematic for rooms, unless one wants to spend a fortune and real-estate on bass traps effective at 50Hz. It's like what Donald North said, once I did it, I wouldn't want to go back.
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Have you considered doing a full mirror of the drivers? I don't think I've ever seen this done in a fully open baffle configuration.
(http://nerds.dk/files/HighPerformanceAudioMontanaMasterReferenceMidt.jpg)
I'm actually not pushing the 15" woofer hard with compensation. Just a 3db boost to extend it down a few Hz to 45-50Hz. Letting a sub take over below that.
So really no need for another woofer considering my use is at low to moderate volumes. Adding another woofer would be too problematic because it would reduce the excursion too much. There's an ideal loudness level that drivers like to be driven at. Too little excursion = small signals might be absorbed by the surround, spider, etc.
I'd add an extra woofer if I wanted a headbanger setup.
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Well, one of the Moth Cicada drivers started to distort recently. I guess it was matter of time with these being stuck in an equipment locker through ten or so summers in Calabasas. It did get me to re-thinking. Perhaps a simple + wide ranger might be a better idea. I really liked the Cicadas as the only thing between them and the amp was a single cap. So much less complexity.
Going back to the Alpair 12P paper 8" driver with 92db sensitivity. Just bought two from Madisound. We'll see how well this driver works: http://www.markaudio.com/Plans/itemlist/category/26-Alpair-12P (http://www.markaudio.com/Plans/itemlist/category/26-Alpair-12P). I'm glad Markaudio is making paper drivers now. The metal drivers of their prior generation I was always scared of. We'll see if the specs with the A12P are BS or not, or if it sounds as good as the manufacturer makes it out to be.
The other choice would have been the Dayton point source 8": http://www.parts-express.com/dayton-audio-ps220-8-8-point-source-full-range-neo-driver--295-346 (http://www.parts-express.com/dayton-audio-ps220-8-8-point-source-full-range-neo-driver--295-346). But I have servere reservations with the Dayton being paper/kevlar. I'm not a big fan of kevlar drivers. See peaky response: http://www.parts-express.com/pedocs/brochures/295-346-dayton-audio-ps220-8-brochure-9530.pdf (http://www.parts-express.com/pedocs/brochures/295-346-dayton-audio-ps220-8-brochure-9530.pdf)
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Just get Devialet's new Phantom (http://images.computeraudiophile.com/graphics/2014/1216/DEVIALET-Phantom-Press-Release.pdf) speaker. It has Heart Bass Implosion®.
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Wow, I wish you were kidding.
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I need to hear that
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Is that something from the JJ Abrams Star Wars movie?
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Proly a hybrid. It's got "SAM processing"...
(http://stuarte.co/wp-content/uploads/2014/01/LOTR-Sam-Gamgee-says-potatoes.gif)
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Just get Devialet's new Phantom (http://images.computeraudiophile.com/graphics/2014/1216/DEVIALET-Phantom-Press-Release.pdf) speaker. It has Heart Bass Implosion®.
Wheatley??!!
https://www.youtube.com/watch?v=xeKMS62GrTI
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Well, getting back to the Alpair 12P...
SYSTEM DESCRIPTION:
Alpair 12P 8" mids/high 300Hz first order high pass
Eminence Beta 15" woofer for OB bass 300Hz 2nd order low pass
Hsu Sub 10" woofer 20 to 50Hz where OB rolls off.
(http://www.changstar.com/index.php?action=dlattach;topic=2008.0;attach=8301;image)
The Alpair drivers are not bad at all for approximately $320 per pair. Madisound provided me with pairs matched at the same resonant frequency. The marketing materials on the MarkAudio website and blather on DIYAudio make it seem like they are the second coming of Jesus or something like that - requiring the use of the most exquisite resolving tube amps with uber transformers. I can assure all of you that is most certainly NOT the case. However, the drivers are quite good and very appropriately priced for their performance. I think they are almost on par with the Fostex Sigma series drivers more or less depending upon your priorities - some things are better, some things are worse.
PROS:
- Extremely detailed mids - surrounds are thin, spider allows easy movement
- Fairly efficient - as efficient as the Moth Cicadas when in effective use
- Good smooth frequency response characteristics for a wide-bander
CONS:
- Does not extend past 10kHz - no air, so sense of space/venue is not quite there - definitely needs a super-tweeter
- Paper coloration - the paper cone is two-layer and quite thick - tapping on it produces this coloration - good thing is that one gets used to it, until one hears something better without materials coloration
Attached below:
- First Attachment: Frequency response at sitting position.* Very nice flat mids. Little bit bumpy in high bass and lower mids, but this is expected interference pattern for OB. I didn't bother to EQ the OB interference bumps out. Keep in mind this is a in-room at listening position measurement, not a microphone wand at 1 meter away. In essence, performance is extremely good, other than the HF roll-off.
- Second Attachment: FR per Mark Audio spec sheet (moral of story: never trust speaker spec sheets. I'm not getting anywhere near the treble extension spec sheet says I should; sometimes I do though - the spec sheets from Seas from example have been pretty darn accurate)
* Light digital PEQ applied as follows:
1) Subs and woofer (no more than -/+ 3db at four points)
2) Alpair 12P has -4db notch at 3700Hz and a +3db treble shelf past 10.5kHz
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That explains why I really liked these. FWIW I think these were better sounding than the Fostex sigmas you had last time I came over. Those had a much more obvious coloration/grain to my ears. But I don't suppose you've tried those on the OB yet so maybe they'll be an epic win there.
if you measure it on-axis 2" away it'll probably match up with the spec sheet.
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I assume you want to keep reasonable efficiency.
Here's my idea: A big soft dome (Audax TW034 in a waveguide) and a pro midrange driver (dual 18sound 6ND430 or a single b&c 8MDN51). Using your choice of (active) bass drivers.
For bass drivers, check out this guy, maybe you can work out a deal:
http://www.ebay.com/itm/Acoustic-Elegance-Dipole-15-D8-15-woofers-Dual-voice-coil-4-Ohm-total-/251743145720?pt=US_Pro_Audio_Speaker_Drivers_Horns&hash=item3a9d0f8ef8
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For bass drivers, check out this guy, maybe you can work out a deal:
http://www.ebay.com/itm/Acoustic-Elegance-Dipole-15-D8-15-woofers-Dual-voice-coil-4-Ohm-total-/251743145720?pt=US_Pro_Audio_Speaker_Drivers_Horns&hash=item3a9d0f8ef8
We've both been eyeing those but I can't justify the cost personally. Especially now that I want to move away from OB
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@eug: Thanks. Picked two of those AE's up. I would have preferred the LO15 instead of the Dipole15, but heck, at that price, hard to turn down and not going to be picky. The DP and LO are close enough.
It's funny. I just had a conversation with Donald and the designs and how certain requirements lead to similar implementations. I did consider the tweeter (waveguide) idea + mids. Since I'm keeping the x-over simple first order and don't like vertical lobing (with my listening habits, I'm OK with beaming, but I just can't stand vertical lobing), I'd probably end up with x4 midrange around the tweeter, in essence a large co-axial, just like what Donald North did below. The trick of course is to find a good sounding midrange, and for this reason I'd probably avoid pro-drivers in the mid to highs. Pro-drivers tend to handle hundreds of watts and have stiff suspensions which tend not to work well in the home and also sort of goes against my detail/resolution sensibilities.
(http://www.dnaudio.com/seqpic3.jpg)
On the other hand, I just picked up Lowther DX-3s for cheap.
(http://www.quarter-wave.com/Project04/DX3_med.jpg)
They are really good sounding. Better than the Moth Cicada drivers. Fast, hyper-resolving, amazing transient response. Unfortunately, the Lowthers have a slightly rising response and are very hot up top straight on, even more so than the Cicadas. This means digital EQ or a notch filter or shelf filter or a strange phase plug, or a combination thereof. +10db from 8-11kHz. That's just nutty bright / annoying (even off-axis). Those are someone else's measurements below, and they are consistent with quick measurements I have taken so far.
(http://www.quarter-wave.com/Project04/Dx3_2.jpg)
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Holy balls. I just realized you take your speaker measutements at 100dB.
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... you take your speaker measutements at 100dB.
With industrial ear protection?
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So I picked up the Acoustic Elegance Dipole 15 from ebay.
(http://www.aespeakers.com/images/drivers/Dipole15-front.png)
These things are heavy. The weigh like 5 times more than the Betas. The paper cones are treated with a layer of semi-sticky stuff on the front size. Let me be somewhat succinct:
I prefer the $79 Eminence Beta 15As. I stated previously that I would have preferred the AE LO15, but figured the Dipole15s would be suitable. The crucial thing that I did not take into account is that the Dipole15s have sucky efficiency at 90db. (The LO15s are 93db). My preference has always been for higher-efficiency drivers. Although I would be generalizing, for some reason, higher-efficiency drivers tend to sound "faster" to me. In comparison, the Eminence Beta 15A's rated efficiency is 98db - and this jives with my observations using both drivers (at least relative efficiency differences between them).
The AE Dipole15s do a few things better. They are better damped, they have less of a paper coloration, they have a tighter more high-fidelity sound. What they lack is the rawness, energy, snap, punch, and speed of the Betas. Although per spec, the Betas have a Qts of about 0.5 and the Dipole have a Qts of about 1.0; the Dipoles in the 2' baffles roll-off in the bass near the same point around 50Hz - maybe a few Hz lower. In theory, the Dipoles should extend lower. I suspect the following causes: width of the baffle is primary limitation, specs for the Beta 15 are wrong - the Qts is higher - probable given the cheap light magnet.
I wouldn't say the Dipoles are worse. It's just that I prefer the liveliness and uptempo nature of the Eminence Betas. The Dipoles have a hard time keeping up with the Lowthers.
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Possible wear-in issues? Any idea how heavily they were used before?
Mind posting FR measurements on axis with the woofer? I'm curious if these do really extend flat to 2k. How are you crossing them at the moment?
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No idea how much they were used before. Put the Beta 15s back - so much better. More resolving, faster. Hits on the beat. Snaps.
The AE Dipoles probably would extend flat to 2k since the cone is damped with a later of glop over it. I expected better, but maybe the Qts of the AE Dipole is simply too high at 0.94. I should swap in your Eminence Alpha 15s and see what happens. Then again, I've always liked the lightweight thin paper cone sound for big woofers, JBL, Altec, Beyma, Eminence, etc.
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I would describe the Alphas as a fast but muddy sound. Becomes non-linear at high SPLs as you can imagine.
I'm just surprised you're not getting any more extension out of them. Super low Fs and high-ish Qts should be a major win on paper. No worries if you don't like them; you know I'll buy them off you eventually.
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Yeah, the Dipole 15s are now officially part of the Changstar speaker driver loaner program.
The Dipoles had a better sense of heft or thickness (I actually didn't like this); but with the measurement mic, all the x-over and bass EQ settings were exactly the same as the Betas to maintain optimal response. The only change being volume, cranked up about 5-6db over the Betas.
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Marv , have been meaning to ask you if you have any experience with these drivers
http://www.commonsenseaudio.com/nirvana.html
From what I can make out - same factory / people behind Lowther.
..dB
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Haven't tried them ... yet. Really good pricing. No much info on them.
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There are a few projects on DIYA , found them a while ago when doing some digging for my brother but not seen much about them. Agree that the prices are very reasonable when considering the other boutique drivers.
..dB