ServoDrive ContraBass and B deap 32 - AVS Forum
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post #1 of 15 Old 01-10-2004, 05:39 PM - Thread Starter
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Hi all. I have been reading great things about the contrabass and b deap 32. anybody have any idea what the applications of each are? they are both sold by the same manufacturer, both seem to be awesome, one has a mechanical coupling instead of voice coil (contrabass) while the other has unconventional enclosure. So, which is better??

thnks, Jaime Martin
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post #2 of 15 Old 01-10-2004, 07:11 PM
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I am not sure there is a better bewteen these two. It is more of a "they are just different" sort of thing. I would give a call over to the company and chat with Mark Seaton as he can help you with the differences and you can help him understand what you are looking for.

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post #3 of 15 Old 01-10-2004, 10:25 PM
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They are certainly 2 differenct designs.

The ContraBass is a PR design with 2x15" woofers and 2x18" PRs. It is a 3 ohm load and is around 96-97db efficient.

The B-DEAP32 is dual 12" I believe in a horn loading arrangement, an easy 4+ ohm load and is over 100db efficient. This design allows (requires) placement be carefully considered for best performance. One member of the forum has 2 of these and has an in-room response (with EQ) flat down to 11Hz and has 20Hz and something obnoxios like 120+db.

I'll let you know what a single ContraBass can do in a couple of weeks when I get mine in (waiting for everyone to get back from CES) and have a week or 2 to dial it in. I'm looking to get my old Maxell poster out again :D

I am serious...and don't call me Shirley.
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post #4 of 15 Old 01-11-2004, 12:46 AM - Thread Starter
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Excellent bpape! Any reason you did not choose the contrabass? I heard the contrabass was originally developed to call elephants in the wild through long distant low frequency signal. Wonder how big your theater needs to be to appreciate a wavelength of 14hz :-)

I think "thebland" here also has the bdeap32. Hope he chimes in.

I was doing a google search two days ago and came across a guy who does sound research and was plotting out effective sound at 20hz, I believe. He domonstrated several color "areas" in a room which he was able to detect a 20hz signal at significant sound pressures. He used a horn subwoofer and placed it in a corner (front left), unloading the woofer's "mouth" onto the left wall, about 3 feet from that wall. Then he oriented the mouth several degrees and in several places in the front of the room. At one point, he switched the cabinet of his subwoofer so that it was similar to the bdeap32, placed it about 1/3 way from the left wall, but with the mouth facing the front wall (unloading onto the front wall at an angle-so that the rectangular box was sticking out at on end and close to the wall at the mouth end). It showed near linear response throughout the room and appeared to have the best response of all. The author even commented that this was similar to the bdeap32! From this I gather that in a rectangular room, placing the bdeap32 at an angle with the mouth end close to the front wall and the other end away at about a35-40 degree angle will probably give the best bass response. It was an interesting project.

let us all know how your project works out. What amp and how many watts will you be using?

jaime
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post #5 of 15 Old 01-11-2004, 12:47 AM
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You may want to contact Jeff (theBland) he is running B-DEAP's I believe. I think the difference is a matter of wattage and output, no frequency.

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post #6 of 15 Old 01-11-2004, 12:51 AM - Thread Starter
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Hi hometheaterguy. Looks like you posted just as I was finishing up my post. thnks for confirming about "thebland". I have PM'd him on other subject. He's a nice fellow!

Jaime
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post #7 of 15 Old 01-11-2004, 12:58 AM
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Hi Jaime,

Yes, Jeff is truly the "KING of BASS". One of these days I am heading to his bass bowl to have some ultra-hi dB fun. One of these days I will have Jeff and Mark design me some slammin speakers.:cool:

A veteran is someone who, wrote a blank check Made Payable to 'The USA, ' for an amount of 'up to and including their life.'
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post #8 of 15 Old 01-11-2004, 01:57 AM
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I think Dan Wiggins and Dr. Hyre are the kings of bass. :D

After hearing Dan talk about displacing 450L of air with a single driver... :eek:
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post #9 of 15 Old 01-11-2004, 02:00 AM
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Dunno, it would take a lot to take Jeff's title away.

A veteran is someone who, wrote a blank check Made Payable to 'The USA, ' for an amount of 'up to and including their life.'
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post #10 of 15 Old 01-11-2004, 08:36 PM
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If you are looking for unconventional check out Cult of the Infinitely Baffled.
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post #11 of 15 Old 01-25-2004, 09:26 PM
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From my understanding of the design, the wide side of the BDEAP32 functions as part of the horn mouth. Would flush mounting the BDEAP32 into a wall create a large mouth and possibly a lower F3? I posted this on the Servodrive forum but recieved no answer. Perhaps if Mark sees this he can answer.
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post #12 of 15 Old 01-25-2004, 09:38 PM
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I don't know if it would lower the F3, but if the sub(s), center and mains where keep on the same plane (alignment) and the mains on-axis (the center could be recessed and the mains towed) flushing a horn loaded cabinets would not create problems.

A veteran is someone who, wrote a blank check Made Payable to 'The USA, ' for an amount of 'up to and including their life.'
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post #13 of 15 Old 01-26-2004, 06:12 AM
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JMartin,

Sorry, I kind of lost this post.....

I DID choose the ContraBass. I will be connecting it to my system as follows:

LFE out of Theta CasaNova -> Symetrix 303 (Convert from unbalanced to balanced)

303 -> Symetrix 551E (5 band fully overlapping parametric EQ)

551E -> Crown MicroTech 1200 running in Parallel Mono (around 800W into the ContraBass' 3 Ohm load)

Things have gotten bogged down as I helped find a buyer for the other single ContraBass. Mine is supposed to be shipped out today so hopefully, I can play with it a little bit before getting ready for superbowl....

I am serious...and don't call me Shirley.
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post #14 of 15 Old 01-27-2004, 01:48 AM
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Hi Catchphrase,

See the original thread on our forum where I posted a response to your question: B-DEAP Loading Explanation

Quote:
Originally posted by hometheaterguy
I don't know if it would lower the F3, but if the sub(s), center and mains where keep on the same plane (alignment) and the mains on-axis (the center could be recessed and the mains towed) flushing a horn loaded cabinets would not create problems.
Physical alignment of the subwoofer relative to the mains is a waste of time, and in fact is incorrect due to the group delay inherent in any subwoofer, which is then compounded with the delay resulting from the low pass filter employed in the bass management. If you actually measure the acoustic output, the sub will always be "late to the party." You can better adjust for this by telling the processor the subwoofer is as far as the arrival of sound indicates, regardless of physical position. What the processor does in this case is further delay the mains to match the arrival of the subwoofer... Or at least that's what it is supposed to do! :mad:

In the case of the B-DEAP-32 there will be an additional 7-12' of delay due to the horn path length and the orientation of the subwoofer. Correcting for this is part of the calibration process. Properly accounting for this can be beneficial to most any system, not just with the B-DEAP. We noticed a significant improvement in Anthony's system(mentioned in other threads) with a ContraBass.

Cheers,

Mark Seaton
Seaton Sound, Inc.
"Make no little plans; they have no magic to stir men's blood..." Daniel H. Burnham
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post #15 of 15 Old 01-27-2004, 11:30 AM
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So Mark, in theory, or in a design you have done, could you put a pair of B-DEAP's and a L, C, and R SPL cabinets Jeff currently uses behind a THX Micro-perfered screen, than a wall behind these cabinets. That way you would not see anything. Then you could delay the center, subs, etc.

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