CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => Speakers => Topic started by: OJneg on April 07, 2015, 01:36:47 AM
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I'm going to design and build this guy from scratch. The goals outlining this project go as:
- Must be relatively small form factor. Height isn't a huge issue, but depth is if we're gonna put it on a desk
- Flat response in near-field listening position (this is actually easier for a small monitor than it is for the big mothatruckas)
- 2nd order (max) electrical filters
- Achieve reasonable bass extension, but we're likely going to need to augment with a dedicated subwoofer for ultimate sub-bass extension. This is an acceptable compromise given the nature of the application
- At the same time, it can't sound like a boomy mess even if positioning is less than ideal. This calls for a sealed cabinet
- Must be more resolving/accurate/technically capable than your average headphone. This is so I can scoff at people who think their headphone collection is the shit
Questionable FR: http://www.changstar.com/index.php/topic,2275.msg77945.html#msg77945 (http://www.changstar.com/index.php/topic,2275.msg77945.html#msg77945)
Using some pricy Scandinavian drivers as shown:
https://www.madisoundspeakerstore.com/approx-5-woofers/seas-excel-w15ch001-e0037-5.5-magnesium-cone-woofer/
(https://www.madisoundspeakerstore.com/images/products/w15ch001.jpg)
https://www.madisoundspeakerstore.com/scanspeak-soft-dome-tweeters/scanspeak-revelator-d2905/9900-00-1-tweeter-textile-dome/
(https://www.madisoundspeakerstore.com/images/products/preview/d2905_9900.jpg)
Cabinets are almost finished. Need to finalize crossovers and figure out clever way to flush mount drivers with given tools.
(http://i.imgur.com/YVksNsi.jpg)
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Yikes, that's $1k in drivers alone. So you're going with biamping and active crossovers? Any porting in the enclosure?
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Wow OJ... I probably won't ever be able to hear how they sound, but I'm looking forward to measurements!
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Yikes, that's $1k in drivers alone. So you're going with biamping and active crossovers? Any porting in the enclosure?
No, passive and sealed
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Wow, I wonder how you got those drivers? Added up still cheaper than most mid-fi headphones.
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Thats some badassery going down here, which sub driver would you be using? The sub drivers I imagine would make most of the cost really.
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How do you plan on dealing with early desk reflections?
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How do you plan on dealing with early desk reflections?
Most pro monitor companies do it via a waveguide, but that's not an easy thing to DIY at all. Good performing waveguides are generally computer modeled. Assuming that's not an option in this case, I might suggest trying different tweeter surround options.
(http://audaud.com/photos/uploaded/MainSpkrSurr.jpg)
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What about using tweeters with limited vertical dispersion patterns?
Also keep in mind that the woofer might also suffer from early 'floor' reflections. The result would be severe comb effect.
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What about using tweeters with limited vertical dispersion patterns?
Also keep in mind that the woofer might also suffer from early 'floor' reflections. The result would be severe comb effect.
Well in this particular case the tweeters are already in place, so it's a bit too late for that. There would however possibly be an advantage to using a tweeter like the RAAL 70-10D, which naturally has limited vertical dispersion. The downside is that it's over $700 for two of them. RAAL has developed a smaller and more affordable version for OEMs which is used by Ascend Acoustics and Philharmonic, but I don't think you can buy it for DIY. There are a bunch of cheap ribbons from Fountek and Hi-Vi, but they're pretty much all crap. Much more distortion from those than a good Scanspeak Revelator.
The option that I'm curious about for dealing with this is the MTM approach, which has inherently limited vertical dispersion, and no need to tilt the cabinet back to time align the drivers. I'm not sure how MTMs behave in the nearfield though.
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Too answer all of the above succinctly:
I already have a good idea of how a 2-way (cone & dome) performs on my desk. It's good. Even with $15 drive units it's better than most headphones. The idea of this project is to scale up the driver capability and see what sort of concrete gains I can get out of it. I'm not going to worry about the flurry of acoustic issues that are always there with speakers.
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Rest of the components came in yesterday and I finished putting them together today.
(http://i.imgur.com/Cx38tt4.jpg)
(http://i.imgur.com/I4Mm7m3.jpg)
Took care to use recessed binding posts, much nicer for the application
used pricy flat-foil inductor in series with woofer
Some minor nicks on the baffle cutouts, nothing that bothers me. I'll probably apply some tung oil later. Just started listening tonight. More to come.
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Wow that is a strikingly shallow enclosure. I never see them like that. Always assumed it made it sound bad
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Wow that is a strikingly shallow enclosure. I never see them like that. Always assumed it made it sound bad
Still adjusting cabinet filling. Might need to stick some dynamat on the rear if I feel that the shallow depth is a problem.
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No dynamat. Use this:
http://www.parts-express.com/sonic-barrier-3-4-3-layer-acoustic-sound-damping-material-with-psa-18-x-24--260-530 (http://www.parts-express.com/sonic-barrier-3-4-3-layer-acoustic-sound-damping-material-with-psa-18-x-24--260-530)
or this:
http://www.parts-express.com/sonic-barrier-1-1-4-3-layer-acoustic-sound-damping-material-with-psa-18-x-24--260-535 (http://www.parts-express.com/sonic-barrier-1-1-4-3-layer-acoustic-sound-damping-material-with-psa-18-x-24--260-535)
Consider use of bigger box and port.
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Marv, is something like this BS?
http://www.parts-express.com/acry-tech-acoust-x-1-gallon-absorption-coating-paintable-damping-material--260-105
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So, can one of you build me a better speaker than a KEF LS50 for the same price? :)
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Marv, is something like this BS?
http://www.parts-express.com/acry-tech-acoust-x-1-gallon-absorption-coating-paintable-damping-material--260-105 (http://www.parts-express.com/acry-tech-acoust-x-1-gallon-absorption-coating-paintable-damping-material--260-105)
Never used it. Probably no different from roof asphalt stuff for three times the price.
So, can one of you build me a better speaker than a KEF LS50 for the same price? :)
Possibly, but if you like and want the LS50 sound, get an LS50. The mini-monitor OJ is building above will probably sound better than the LS50. Then, again those Seas and Scanspeak drivers are extremely expensive.
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By the way, does anyone have any comments about the jbl 3 series 2 way monitors?
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Yea, no dynamat crap. Too messy and not as effective as people say it is. Plain ol pink fluffy fiberglass is lot better but, your cab is very small(depth wise specifically) especially for a bookshelf speaker. I wouldn't get that paint goo either. Can find very similar local home dept or even Walmart hardware department. They have paint/ spray on rubber as well but, I wouldn't use it for internal enclosure section.
I never tried foam stuff that Marv listed but, it does look good and best option so far. I only ever used plain ol' fiberglass with sometimes combination of fiberfill/pillow stuffing. Never did anything fancy ever with speakers. I know some people fill their enclosures with bags of sand or concrete but, never found point of that either.
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So, can one of you build me a better speaker than a KEF LS50 for the same price?
That's an interesting question that you always hear people go back and forth on audio forums. If KEF were just buying drivers from Viking-land and putting them in a box then I would say yes. Clearly any DIYer is going to be able to build something better for the same price; I think we all know the 1/5 rule. But the LS50 has special qualities (proprietary coaxial driver, special curved baffle) that is hard for a DIYer to copy in his garage. Whether all that tech really delivers in terms of sound quality is a different topic altogether.
I've liked the LS50 when I heard it in the past, and right now I am having some issues with this guy sonically. I destroyed my microphone so I'm trying to tune things by ear right now which is turning out to be rather difficult. I do think these are easily on the level of something like an LS50 but I'd need a direct comparison to be sure. Certainly different design goals for each.
I just remembered that my brother is back in town and so are the LSR305's I gave him. I can try to set them up for a quick comparison.
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Never used it. Probably no different from roof asphalt stuff for three times the price.
I've used roof sealer before to coat the inside of headphone cups. I don't recommend it. For concrete, shingles, etc it's all fine, but for anything that you'll be working with hands-on, it's a world of mess. If the more expensive stuff actually fully dries into a non-tacky surface, I'd maybe try it again.
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Having heard many well acclaimed studio monitors in the last six months, I'd say that tonality and THD wise the LS50 isn't that special. Where it really excels is dispersion geometry - sweetspot is quite wide and high frequency rolloff when moving to sides is rather gradual.
Pretty sure that one could build a better resolving bookshelf speaker with more low end reach for the same money, but it's really the unique summing properties of the coax driver that sets the LS50 apart.
What would really interest me is to use my LS50 serial numbers to get a pair of coax drivers and make a floorstander with these and a pair (or two) of ten inchers. Tri-amp and DSP cross the drivers.
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(http://i.imgur.com/5CNkv6n.jpg)
Set up like above for comparo. Hilo LO > TOCOS pot > Parasound Zamp > NegMonitor vs Hilo MO > LSR305 balanced TRS input set for 4dBu
Started going back and forth and went WTF. Vocal on NegMonitor was effed to hell. Tried sitting on some books but it wasn't just the off-axis response. Of course I turn them back vertical and things lock into place. So much for quick switching; have to give each the spotlight and listen
Biggest difference is bass volume. The 305 has a lot more mid bass volume, akin to my OSMT. Sealed cabinet is never going to extend as low. In this case though it's too much given the positioning (rear of cabinet is <9" from wall). I did try pushing down LF trim but it needs more than 2dB. The reason I made mine sealed in the first place
Other than that, it breaks down like this
LSR305
+ More bass punch
+ More vibrant, faster
+/- Hyper-dynamic JBL sound
- Slight artificial tinge on acoustic instruments
- Cuts out some low-level stuff
NegMonitor
+ More precise, more nuanced
+ Bass doesn't overhang
+ Deeper stage, disappears better
+/- More reserved, consistent sound
- Congested lower mids, upperbass
- Less dynamic
Overall I'm fairly happy that I've got the tonal balance pretty close to the 305, considering I know the 305 to be quite flat. The 305's do tend to grate on my ears after a while, for whatever reason. Almost like a technicolor sort of effect. Probably because they're hyper-dynamic with too much port energy. After listening to the 305 for a good part of the day and then going to AB against the NegMonitor, the music really does start to wash over you. I'm so happy that these drivers can be so precise and resolving while still having certain euphonic qualities. A lot of precise and resolving headphones are missing that natural quality or are just straight up fatiguing. I can only hope that adding that additional damping behind the woofer will clean up the lower-mids and add even better blackness. The fact that these are still comparing well in what is essentially a raw cabinet gives me hope.
BTW, the 305 is still way better than any headphone <$1000. Highly recommend for headphone lewsers who are interesting in getting into real hi-fi :D
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Hard to tell anything without a calibrated mic in front of the whole setup.
What was the rationale behind enclosure dimensions? My way of doing it would be to measure each driver in the enclosure without the crossover, use two digital outputs and two amp channels to create an optimal digital crossover and then try replicating it with passive components.
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Enclosure dimensions were based on recommend .15ft^3 for Seas in sealed enclosure. I did try playing around with values in WinISD but I found the recommended would yield the best results, as it did.
That method sounds like a lot of unnecessary complication. I basically design crossovers in LTspice without ever using a mic. The trick is including the RLC models (for example, the tweeter has a resonance just like the woofer and the woofer has a rising impedance due to voice coil inductance). You also need to know where the breakup points are and guesstimate how many dB you need to be down at that point. Stick to the book, use 2nd order slopes, plug and chug. Choosing a 2200Hz instead of 2000Hz isn't going to give you sonic nirvana.
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Looks fun.
I wish I had the space for speakers...
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take it this is nearfield listening you are doing OJ?
YOu need some bracing in that cabinet to break up the bass modes from the woofer. That could help with the congested midbass region.
In my expereince, sealed boxes work great , except they end up being a fair size bigger than ported enclosures. The bass response is much tighter when done right (as in a 10 inch woofer atleast lol).
How is the JBL for regular room listening? Like in the background or sitting 10-12 feet away?
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How is the JBL for regular room listening? Like in the background or sitting 10-12 feet away?
Excellent. It needs more room to open up and show what it can do.
This cabinet is so small and tight I don't think bracing is necessary. Mainly reflections from rear of woofer methinks.
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Mainly reflections from rear of woofer methinks.
yeah! exactly. and bracing helps with this.
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I find it interesting to learn that a few of the classic 2-way monitors also share the sealed cabinet design. LS3/5A and Yamaha NS10 for example. Although I don't think either of those designs are up to snuff with modern 2-way monitors.
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Hey, those look like my drivers....
Try a bigger cabinet with a port with the Seas. The port might be a bitch to make because of lack of space. That will open up the Seas a bit - give it some and dynamics, even in the mids. The Seas are extremely inefficient once baffle step is considered, so it will never be a super dynamic and lively sounding driver.
Another consideration if you don't play super loud... drop the x-over of down to 1600Hz. Those Scanspeak tweeters will handle it. They are very slightly horn loaded after all. Those are one of the best tweeters I've ever heard.
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Yes, you mentioned that. After a fair bit of tuning and damping, I've accepted that the sealed cabinet sound will not go away. A compromise I'm willing to live at this point.
I'm going to order one of these flat packs and stick the Alpha 15A's in them. I'm guessing those drivers sound a lot better in a cabinet (less excursion) than on an open baffle.
http://www.parts-express.com/denovo-audio-knock-down-mdf-30-cu-ft-subwoofer-cabinet-for-dayton-audio-15-ultimax-subwoo--300-7082
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BTW, the 305 is still way better than any headphone <$1000. Highly recommend for headphone lewsers who are interesting in getting into real hi-fi
Goddamnit. I have been struggling with the realization that speakers are actually fucking awesome. I was lurking the wide world trying to figure out where to start. I remembered chatter about the yamaha hs5/8 and the jbl 305/8, then I remembered the negmonitor thread, and then I read this specific line. There should probably be a thread dedicated to "so you've decided to buy a gun speakers..."
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Ordered one of these, should get here this week:
http://www.parts-express.com/denovo-audio-knock-down-mdf-30-cu-ft-subwoofer-cabinet-for-dayton-audio-15-ultimax-subwoo--300-7082
Need to revive DIY capsule mic so I can take useful measurements
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The journey continues:
http://www.changstar.com/index.php/topic,2701.msg77601.html#msg77601
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Here's the response 1 m away from baffle. I pulled the monitor away from the wall for this. A lot more bass than indicated when in position. That's pretty much what I'm hearing but take measurements with grain of salt as I'm doing it with large diapraghm condenser with cardiod pattern. Apply inverse of FR of what's below in your mind.
(http://i.imgur.com/tVIpm2b.png)
(http://i.imgur.com/6uJyZu5.png)
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At listening (where my head is) position with subwoofer engaged:
(http://i.imgur.com/k85Jmgu.png)
Can't use ARTA here because of crossover needs.