Has SVS met its match? (1 Viewer)

[Mark Seaton]

Indeed, the B-DEAP 32 is an interesting animal. When we creatively use a B-DEAP sub in a confined home theater, we could in one way consider it a dual 12" sealed sub below maybe 16-22Hz. Above this frequency there is progressive loading from the horn, where we then reach the flat passband in the 28-32Hz region. You will see a gain of 10-18dB in the passband over that of these drivers if they were in a sealed box. In this range, we need 1/10th to 1/60th the power which would be required from the pair of sealed subs. What gets interesting is that the region where the drivers operate more like a sealed box, a solidly constructed room will begin to significantly augment the low frequency reproduction. This is the same effect that occurs in a car's cabin, yet at more than an octave lower, and typically in a much more lossy space. In most any dedicated room, you also have an initial gain in response below the 1/4 wavelength equivalent of the ceiling height, mixed in with the effects of the same factor with respect to the other dimensions of the room, where you ultimately end up in the "pressurization" region of the room. Below this point, you are effectively modulating the pressure of the room, as sound is not really propagating as the distances are small relative to the room's dimensions.

While many like to conceptualize sound as waves, we should remember that all our ears react to is the rate at which the air pressure modulates at the eardrum. As such, we most certainly still "hear" the bass below this "pressurization" region.

One of two reasons for using a pair of B-DEAPs in a room is to provide more displacement below the loss of horn loading. A single B-DEAP32 has more than enough output for any home theater above about 30Hz. By operating well below its operating limits, distortion and compression remain exceedingly low. Distortion does rise below about 30Hz, but I haven't had a chance to measure distortion in-room.

Conversely, the ServoDrive mechanism in the ContraBass has the unique benefit of maintaining, if not improving linearity at its upper output limits. The ContraBass should offer more peak output below 20Hz than a B-DEAP 32, yet the B-DEAP will have 10-20dB greater peak capability above 25Hz with the unique phase and impulse characteristics of an efficient horn.

Best Regards,

 

[Sebastian]

When did SVS become the bench mark for subwoofers?

 

[Craig Chase]

Sebastion... You were at the meeting where we voted on this, don't you remember ?

 

[ScottCarr]

Craig
I was on phone con, I thought we were voting on having a meeting to determine if we needed to have a meeting to schedule the meeting on making that exact topic.

The proposal was, We are voting on having a meeting to determine if a meeting is needed to schedule a meeting to decide if SVS Benchmark.

If I remember correctly we determined SVS to be a subwoofer and not a benchmark so no further meetings were scheduled.

 

[Sebastian]

Ah silly me getting a subwoofer confused with a markedbench or is that benchmark? Is there a difference between a markedbench or a bench mark?
Nevermind they are both marks.

I have a hard time staying awake at these meetings. Thanks for keeping me up to date.

Hmm I used to have buddy named Mark.

 

[ScottCarr]

Sebatian
Yes you did have a hard time staying awake at those meeting. Fear not, our next meeting will be more exciting. We will be discussing why we are selling our equipment and turning to Bose for all our audio needs.

Oh yeah, while you were snoozing we determined a Bench Mark is the potential a dog ponders. A marked Bench is the execution of that ponder.

 

[Sebastian]

Thanks a lot Scott! I know I can always count on you to fill me in.
Hey has any of meetings discussed what we are doing for my 2nd anniversary for being a member of HTF come April 14?
Last year we did nothing, because it was too close to the tax cut-off so everyone was at the post office. Well, that what they told me anyways.

Sorry I missed yours, I am sure it was a blast.

I think we offically hi-jacked this thread. Sorry Ed.

 

[Ned]

SVS is the benchmark for value.

 

[Arthur S]

Mark

Thanks for the detailed response to my post.

If you wish to read the extensive report conducted by Don Keele on the HSU 1220 that includes distortion measurements you can readily find it on the "Reviews" page at HSU.

I would still like you or someone else who is familiar with the B-DEAP to post the price of the B-Deap 32.

I would greatly appreciate your response.

Thanks

Artie

 

[Mark Seaton]

Hi Artie,

My apologies. In writing the response, I forgot to post the suggested list price of $3,450 each. For now, both the ContraBass and the B-DEAP32 are passive.

Best Regards,

 

[Craig Chase]

Mark - As you would know, I have never owned one of your subwoofers... though that could change at some point...

Considering the Contrabass against other subs available... it is quite the engineering feat...

When Widescreen reviewed the contrabass, they discovered it could deliver 112 db at three meters... and do it on a continuous basis.

When most companies test a sub, the max SPL is on a "pulse" basis, at two meters corner loaded, or one meter if not.

The Keele review shows the 1220 can achieve 104 db/16 Hz at two meters on a short term sine wave, 110 db with room gain on a "pulse"

This basically means it would take 4 1220's and appx. 800 watts of amplifier (feel free to check the math) to match what the contrabass can do with a continuous basis...

The 4 1220's would be able to maintain that level for 3-4 seconds...

The Contrabass could do it (112 db/16 Hz/3 meters) all night... with a 200 watt amp

There is a reason why the contrabass is considered to be worth $5000... in fact, a bargain....

Mark Seaton... Feel free to correct me ...

 

[Mike_Skeway]

Craig, you know you want (need) to get a ContraBass and a B-DEAP32. :p)

I am thinking about a few of them for my PA. The question would be which one? Hmm, Mark, I may need to talk to you about that one of these days.

 

[Craig Chase]

Mike - Even though I know the Contrabass is a killer, the sub I have now are more than my ears can take...

then again... at some point, maybe I will grab a contrabass !

 

[Ned]

My friend has dual contrabass's and in general, the extra SPL is mainly the low hz stuff, which isn't "eary bass". It's the sort of bass that rumbles the room, flaps your clothes, and socks you in the chest cavity. I never really get the feeling of "ow my ears hurt" like you do when someone cranks up the higher frequency stuff on a stereo.

 

[Wayne Ernst]

I stumbled across these home theater pics where the owner has the Contrabass - which was finished off with truck bed liner.

Contrabass Sub

 

[Mark Seaton]

Good observations Craig.

I didn't check the exact math yet, but that looks about right. Since I know many are interested in test results, I can tell you to just wait a few months and keep reading the mags... You'll see all sorts of data by summer.

One of the very unique quality of the ServoDrive mechanism is the distortion characteristics with respect to drive level. With any conventional subwoofer, distortion is lowest at low drive levels and increases as it is driven harder. The ServoDrive mechanism is exactly the opposite. As more power is applied to the motor, the more the motor strength dominates the non-linearities and distortion reduces. Distortion is in fact lowest above about 10W of input. Interestingly, ANY signal effectively "biases" the system to maintain lower distortion. As an example, there was a scientific application where our designer used a 500Hz constant signal at low power to maintain the very low distortion needed. This means that content at higher frequencies actually helps lower distortion when in combination with low frequencies. Again, this is backwards from a conventional driver. With most systems, IM (intermodulation) distortion is a very significant problem. In the case of the ContraBass, this condition makes for a lower distortion output, and is a regular situation during playback.

While measurements do give us a good indication of how a subwoofer performs, they are most easily compared when other factors are similar. Radically differing distortion, compression, and dynamic characteristics make direct comparison less intuitive and require more examination.

For those who want to take a look at another interesting install where we hid a ContraBass in an adjacent closet, check out the links to the following pictures:

ContraBass Cavity

ContraBass Cavity Inside

Best Regards,

 

[Craig Chase]

Thanks Mark - The most impressive portion of that is the fact that the 1220 is a really powerful subwoofer... and the two Hsu amps and the 4 1220'2 would run about $3400 delivered... a very good value...

The Contrabass being able to do what it does in a simple looking, 120 pound box is remarkable...

I doubt the Krell Master Reference Subwoofer comes close ... for $30,000...

And yes, a Contrabass is tempting... but it looks like Mark has the review angle covered... no shootout needed ... bummer ...:frowning:

 

[Mark Seaton]

Hi Craig,

Indeed a very competent review is covered, but shootouts are always fun. I'm in and out of town for about a month here. After that I will have the new cosmetic finished and deliverable for the ContraBass, and with the use of the B-DEAP in home theaters Tom Danley is thinking about going bigger and lower with the similar design concept. BTW, a patent was just filed on the B-DEAP(Boundary-Dependent External Air Path) design and utilization.

It is nice that in the market lately there has been a sort of "subwoofer limbo" going on ... "how low can you go?"

Cheers,

 

[Craig Chase]

Mark - Sounds like good stuff... I am looking forward to seeing the high WAF Contrabass....

 

[Mark Seaton]

Well, anything is a WAF improvement over the access panel on the top and the old guitar cloth style grill. This one will be a lot cleaner looking with more conventional looking grills. The access panel and input connector will be on the bottom instead of the top. The re-work of the grill and overhangs will also allow for veneering and possibly custom paint options at additional cost. The form factor is still the same, but we are making some minor adjustments where a total re-design is not needed.

Mike- You are only 2-2.5 hrs north of us. I have done some work with one contractor in your area, but indeed, a few B-DEAPs make for some amazing low end in S-R applications. Feel free to e-mail me or call our office any time.

Best Regards,