B&C 21DS115 23hz 800L TH build - Page 2 - AVS Forum | Home Theater Discussions And Reviews
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post #31 of 44 Old 02-20-2017, 01:03 AM
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Reminds me of the Micro Wrecker response shape.
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post #32 of 44 Old 02-20-2017, 02:26 AM - Thread Starter
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Originally Posted by chrapladm View Post
Anyways for an ultimate 2way center channel I would build Notnyts 2way with a single 15". But there are MANY designs out there that can fit your budget also.
No doubt there are. What I really need to do is sit down with a good speaker design/building book, pg 1, and build up some sort of foundational knowledge. SO ....Okay, I wimped out tonight and pulled the trigger on an option I'd also been considering: I added up what I can sell some of my gear for, to include some amps and crossover units, a few receivers ...yeah, a bit of a hassle to raise the money but it should be no problem. So long as I can keep the budget coming out of my sideline eBay & Amazon selling, I don't feel quite as guilty

So how to uncomplicate the front soundstage until I am halfway competent building/designing?

http://www.jblpro.com/www/products/p...s/eon612#Specs
and a useful review
http://www.soundonsound.com/reviews/jbl-eon-612

3 of them, should be here in a week. I'm solving a problem throwing money at it, but until life settles down a little so I can pursue some pure DIY builds on mains, this ought to do the trick. I know it's not the most musical solution, but the EON's I've listened to were really no slouch either. 350+150 watts continuous, some pretty good DSP onboard. Should meet my cravings for a bit more "headroom", and a matching center channel as well.

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post #33 of 44 Old 02-20-2017, 02:33 AM - Thread Starter
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Originally Posted by chrapladm View Post
Reminds me of the Micro Wrecker response shape.
Agreed, very similar. I think that for a single cabinet intended for dual role high level music playback/HT, it is a really pleasing compromise.

This horn turns out a slightly lower tune than modeled, but not by much; designed tune = 23.6hz, actual = 22.2hz

Comparison with Alpine SWS15D4 loaded Microwrecker ... same basic form, just a tad louder
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post #34 of 44 Old 03-19-2017, 03:40 PM - Thread Starter
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Got it measured!

I traded some mails with Lilmike and got lined out on REW and my PC, and got some preliminary sweeps done. He plans to massage the data, do some overlays, and get them back to me. I'll post everything as I get it. For now, it's better than my speculation. Nails 20Hz solidly before tapering off. Useable up to 150 with some good signal processing, according to Mike.

His first reaction to seeing the screenshot I sent him to confirm we were in business:
Lilmike:"Holy crap! That turned out better than I'd expected. I approve ... no wonder you like it."
Me:

I also shot some video of cone motion during an energetic scene from Killer Elite; first onset of the explosion bumped the clip lights on the EP4000 pretty solidly, but that is it. Whew ... first time I've found those on a movie track. BUT, I can't load an MP4 format here. Is there another format I can save it in, convert it somehow?
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post #35 of 44 Old 03-21-2017, 09:26 AM
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Here's a couple plots comparing the model to the measured results. This is not a 100% perfect comparison, as this sub is too big to be taken outside and measured groundplane, so it was measured nearfield. Though not a perfect setting, it is adequate to assess the results of the effort.



Not at all a bad result. The tune looks like it is little lower than predicted, which is also inline with the impedance measurements.



Nice work. Thanks for making the effort to collect some measurements of the result.
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Last edited by lilmike; 03-21-2017 at 09:27 AM. Reason: fix grammar
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post #36 of 44 Old 03-21-2017, 07:00 PM - Thread Starter
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Lilmike, the thanks are mine for all the help and encouragement. This has been a fun, fun project and my enjoyment of the system is just beginning. I don't have a moment's regret choosing this driver and pursuing this build. Both have a lot to commend them. Everything is a compromise and this is no different, but it is a very good one between extension and output, fitting a comfortable range that does the music/HT double duty well, for my uses at least.

It may be a while before I have any serious desire for more of either. SQ is excellent. What's not to love?
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post #37 of 44 Old 03-24-2017, 10:20 PM - Thread Starter
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Here are a few more of the REW windows, with a little effort made to scale them. I'd be happy to get any impressions and interpretations anyone has to share. Lilmike has weighed in that the impulse, group delay, and distortion values are not at all bad:

"Waterfall is well-behaved in-band, no real stored energy except the 21 Hz fundamental and at the peak at 82 Hz. The peak is damped out by 400 ms, so not too bad. Otherwise quite good ...Group delay? Not bad, 70 ms at 21 Hz, 40 at 82 Hz, otherwise under 10. No complaints there."




For a simple build, it seems like a good return on both the $$$ and the low, low effort/complexity build. I did the build with no help, and not so much as a clamp or even a real sawhorse. To make up for the lack of clamping (the best I could anyways) I used a ton of PL 8X and a full box (1 lb) of #7, 2" Spax screws, in addition to a box of regular #6 drywall screws. I have pushed the enclosure pretty hard on some movie tracks (finally found the clip lights on the car bomb scene in "Killer Elite", but just bumped them solidly once), and it is holding together just fine. Egad, that was an EXPERIENCE and no mistake.

COST:
  • B&C 21DS115-8: $513.50, shipped
  • Lumber: Three (3) sheets 3/4" 4' x 8' Purebond birch plywood $149.54
  • Pl 8X, Kregs, Spax screws, 1 1/2" Drywall screws: $36.35
  • Behringer EP4000: $329.99, shipped (I already had mine)
  • $1,029.38
That is not all that bad for that level of performance, really. I consider it a very reasonable outlay. It offers good sensitivity and extension, and will handle enough juice to liven things up nicely. No mistake, I love it It is my initiation into a large horn-loaded enclosure, and it is the best sounding bass I've yet experienced in a home system. Period.
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post #38 of 44 Old 03-25-2017, 03:06 AM
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How/where was that measurement made? Outside (quasi-anechoic?) or at listening position? If at listening position is there any room treatment?

Revel Ultima Salon 2, Revel M106, Revel C208, Yamaha P5000S, Denon X5200, Panasonic 65" VT50, SVS PC13-Ultra
Kef LS50, Parasound New Classic, Focusrite 2i2
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post #39 of 44 Old 03-25-2017, 07:30 AM - Thread Starter
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Originally Posted by donktard View Post
How/where was that measurement made? Outside (quasi-anechoic?) or at listening position? If at listening position is there any room treatment?
donktard, the measurements were made with the horn mouth as close to the center of the media room as possible to get it as far away from reflective surfaces as possible. The UMIK was positioned on the floor, business end of the mic even with the horn mouth. The UMC22 soundcard was plugged directly into the EP4000 amp, so no (intentional) alteration of the signal at all.

I'd love to be able to take it outside and get some anechoic measurements, but a little history on the horn: I wanted a single large horn, and the simplest possible build. I wanted the Loud and Low elements of a system (the best compromise that could be reached at least), so the Iron Law meant "not Small." There is no way to move a large cabinet into/out of the basement due to dimensional restrictions on the old house ... just wouldn't fit. SO, it needed to be built in place, and thus one reason for the desire for a very simple/low-complexity build ... if/when I leave this place, it will simply have to be cut up and scrapped, so why do a fairly elaborate build like the G-horn, Lilwrecker or Submaximus? The time constraints of my school program (last semester toward a degree in Physical Therapy) were also a factor.

So I built it in place.

I am planning some measurements from my MLP this weekend, if I can. I'm interested to see what the room is doing to my signal.

No, it's not the sexiest system on this or any other forum and I could give a squat less. It is a very successful solution to my needs. And minus the cost of the amp and a few odds & ends like terminals and wire, the cost is ~$700. Given the sensitivity on the system, a person could go with a used good quality middlin' sized pro amp and get a ton of output. Attached is a screenshot of the system with 900 watts RMS that a used QSC 900 like I have sitting around, $129 delivered, would model in this system at 1340 watts peak (as per the rated 1.9dB headroom) This is a lot of performance for that price, if a person didn't have an issue with the size (and I don't, within reason).

Here is also a HR prediction of the system sensitivity compared to the well-proven Othorn. That kind of sensitivity approaching 20hz is pretty darn good. Othorn in gray, both systems at 1 watt into rated impedance.
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post #40 of 44 Old 03-25-2017, 08:35 AM
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Quote:
Originally Posted by cattskinner View Post
Here are a few more of the REW windows, with a little effort made to scale them. I'd be happy to get any impressions and interpretations anyone has to share. Lilmike has weighed in that the impulse, group delay, and distortion values are not at all bad:

"Waterfall is well-behaved in-band, no real stored energy except the 21 Hz fundamental and at the peak at 82 Hz. The peak is damped out by 400 ms, so not too bad. Otherwise quite good ...Group delay? Not bad, 70 ms at 21 Hz, 40 at 82 Hz, otherwise under 10. No complaints there."




For a simple build, it seems like a good return on both the $$$ and the low, low effort/complexity build. I did the build with no help, and not so much as a clamp or even a real sawhorse. To make up for the lack of clamping (the best I could anyways) I used a ton of PL 8X and a full box (1 lb) of #7, 2" Spax screws, in addition to a box of regular #6 drywall screws. I have pushed the enclosure pretty hard on some movie tracks (finally found the clip lights on the car bomb scene in "Killer Elite", but just bumped them solidly once), and it is holding together just fine. Egad, that was an EXPERIENCE and no mistake.

COST:
  • B&C 21DS115-8: $513.50, shipped
  • Lumber: Three (3) sheets 3/4" 4' x 8' Purebond birch plywood $149.54
  • Pl 8X, Kregs, Spax screws, 1 1/2" Drywall screws: $36.35
  • Behringer EP4000: $329.99, shipped (I already had mine)
  • $1,029.38
That is not all that bad for that level of performance, really. I consider it a very reasonable outlay. It offers good sensitivity and extension, and will handle enough juice to liven things up nicely. No mistake, I love it It is my initiation into a large horn-loaded enclosure, and it is the best sounding bass I've yet experienced in a home system. Period.


Where did you order your subs from I paid 2080 $ shipped to my door from usspeaker.
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post #41 of 44 Old 03-25-2017, 08:43 AM - Thread Starter
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Where did you order your subs from I paid 2080 $ shipped to my door from usspeaker.
Got mine from SavingsLot. Yeah, anything close to that price point, the DS is a lot of driver for the money. Whew, lot of driver period.
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post #42 of 44 Unread Yesterday, 09:32 PM
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Maybe I should quote your last post.
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post #43 of 44 Unread Today, 11:36 AM - Thread Starter
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Maybe I should quote your last post.
Holy smokes, I have nooooo idea what happened there. Editing ...
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post #44 of 44 Unread Today, 11:53 AM - Thread Starter
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Deleted that weird link ... I was afraid to click on it lest I wind up in the NSA database and wind up with black heicopters paying me a 3 a.m. visit, ninjas fast-roping onto my roof ;-)

I'll try this again. I have a lot more work measuring at my MLP and around the room, as I'm interested in seeing what this horn will do with a little room gain (if there is any). This is three sweeps, two from my MLP and got some major floor - ceiling cancellation, and another position across the room at a comparable distance from the horn mouth.
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