Double Bass Array (DBA) - The modern bass concept! - Page 9 - AVS Forum | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!


Forum Jump: 
 7Likes
Reply
 
Thread Tools
post #241 of 350 Old 01-27-2014, 06:12 AM
Advanced Member
 
AudioJosh's Avatar
 
Join Date: Apr 2003
Location: Toronto
Posts: 645
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked: 99
Actually, I think I like this one better and a little bit cheaper.

http://www.parts-express.com/dayton-audio-rss390ho-4-15-reference-ho-subwoofer-4-ohm--295-469

It likes a smaller box so easier to array more of them.

JoshK on most other audio forums
Quantity only when quality is ensured.
AudioJosh is offline  
Sponsored Links
Advertisement
 
post #242 of 350 Old 01-27-2014, 07:43 AM
AVS Special Member
 
coctostan's Avatar
 
Join Date: Oct 2005
Location: Indy
Posts: 1,960
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 132
What I'd like to see tried is using smaller band limited subs in the rear. I don't see why it would be vital that the rear array's extend below the lowest null and why they would need to be identical to the front subs. They would need to match the output capability of the front subs, but that is easier over a smaller bandwidth.

This would allow the use of much smaller and possibly shallower subs but would still have the same potential effect. The back subs are just active absorption and you don't need it below 20-30hz in most rooms.

Something like 8 of these shallow subs in enclosures designed to be high passed around 25hz: http://www.parts-express.com/pioneer-ts-sw251-10-shallow-mount-subwoofer--297-290

My room has angled walls at the back so I'm not sure if this would work.
sdaddy likes this.
coctostan is offline  
post #243 of 350 Old 01-27-2014, 07:49 AM
Advanced Member
 
AudioJosh's Avatar
 
Join Date: Apr 2003
Location: Toronto
Posts: 645
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked: 99
That is a very good point!

JoshK on most other audio forums
Quantity only when quality is ensured.
AudioJosh is offline  
post #244 of 350 Old 01-27-2014, 09:23 AM - Thread Starter
Advanced Member
 
FoLLgoTT's Avatar
 
Join Date: Apr 2001
Location: Hannover, Germany
Posts: 517
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 90
Quote:
Originally Posted by AudioJosh View Post

You don't get room gain...

This is not true. I have to correct the statement I made a few years ago. A DBA has room gain as every other subwoofer system does. I measured it a few months ago. I was just wrong on that. rolleyes.gif



I think the explanation is that both waves benefit from boundary gain.
FoLLgoTT is offline  
post #245 of 350 Old 01-27-2014, 10:44 AM
AVS Special Member
 
coctostan's Avatar
 
Join Date: Oct 2005
Location: Indy
Posts: 1,960
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 132
Nils, what do you think about limiting the bandwidth of the rear subs in order to use smaller enclosures?

Also, do you think the rear walls need to be parallel to the front wall in order for them to work?
coctostan is offline  
post #246 of 350 Old 01-27-2014, 10:47 AM - Thread Starter
Advanced Member
 
FoLLgoTT's Avatar
 
Join Date: Apr 2001
Location: Hannover, Germany
Posts: 517
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 90
Quote:
Originally Posted by coctostan View Post

Nils, what do you think about limiting the bandwidth of the rear subs in order to use smaller enclosures?

I've never tried it. If done well it could work I think.
Quote:
Also, do you think the rear walls need to be parallel to the front wall in order for them to work?

Yes, I think so. But again I never tried a DBA in such a room. Maybe the result is better than expected...
FoLLgoTT is offline  
post #247 of 350 Old 01-27-2014, 10:48 AM
AVS Special Member
 
coctostan's Avatar
 
Join Date: Oct 2005
Location: Indy
Posts: 1,960
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 132
Yep, I guess I would just have to test it.
coctostan is offline  
post #248 of 350 Old 01-27-2014, 11:00 AM
Advanced Member
 
AudioJosh's Avatar
 
Join Date: Apr 2003
Location: Toronto
Posts: 645
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked: 99
I think the non-parrallel back wall should work fine. It just means you have an averaging effect for your primary mode (slightly lower on the longer depth than the shallower depth). Non parallel sides would be tougher to predict I'd think.

JoshK on most other audio forums
Quantity only when quality is ensured.
AudioJosh is offline  
post #249 of 350 Old 01-27-2014, 12:03 PM
Member
 
mos6581's Avatar
 
Join Date: Oct 2011
Location: Norway
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I've finally completed my single bass array setup and made the first few measurements. I've not started on the back wall treatment yet, and I've not done any kind of EQ so far. Even without this it looks very promising.

Looking forward to getting the back wall finished and start working with the EQ.
The FR on the different measurements are almost the same, as they should be according to the theory, so I hope the EQ job will be easy.

The array is build with 4x2 Dayton HO 12" drivers and they are powered by 2 Crown XTI-2000.
mos6581 is offline  
post #250 of 350 Old 01-27-2014, 03:36 PM
AVS Special Member
 
maxmercy's Avatar
 
Join Date: Nov 2008
Posts: 2,405
Mentioned: 4 Post(s)
Tagged: 1 Thread(s)
Quoted: 55 Post(s)
Liked: 160
Very nice width response similarity!!

JSS
maxmercy is offline  
post #251 of 350 Old 01-28-2014, 07:51 AM
eXa
Member
 
eXa's Avatar
 
Join Date: Jun 2006
Location: Norway
Posts: 192
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 19
Im curious. In a SBA setup, could you place diffusers on the back wall infront of the absorbtion material without interfering with it too much? If so, how big could the diffuser be?

Edit: Thinking something like Perry R's diffuser, just on the backwall, maybe slightly wider depending on room width.

eXa is offline  
post #252 of 350 Old 01-28-2014, 09:44 AM
AVS Special Member
 
cuzed2's Avatar
 
Join Date: Nov 2006
Location: Chicago Area
Posts: 4,523
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Liked: 88
Quote:
Originally Posted by mos6581 View Post

I've finally completed my single bass array setup and made the first few measurements. I've not started on the back wall treatment yet, and I've not done any kind of EQ so far. Even without this it looks very promising.

Looking forward to getting the back wall finished and start working with the EQ.
The FR on the different measurements are almost the same, as they should be according to the theory, so I hope the EQ job will be easy.

The array is build with 4x2 Dayton HO 12" drivers and they are powered by 2 Crown XTI-2000.

mos6581,

Very encouraging and impressive!
Am looking forward to how you are handling the rear wall, also how you will EQ those 8 drivers?
Do you have a build thread for this project?

Cuzed2
CuznEddy Cinema
Officially Hanesamatized on 8/1/09
cuzed2 is offline  
post #253 of 350 Old 01-28-2014, 09:58 AM
AVS Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 5,922
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 428 Post(s)
Liked: 277
Quote:
Originally Posted by eXa View Post

Im curious. In a SBA setup, could you place diffusers on the back wall infront of the absorbtion material without interfering with it too much? If so, how big could the diffuser be?
I think you should download and play with the great QRDude program to get an idea how large diffusers need to be for LF.
Long story short: diffusers are not the solution, but a large depth of absorption might.
A9X-308 is offline  
post #254 of 350 Old 01-28-2014, 10:55 AM
eXa
Member
 
eXa's Avatar
 
Join Date: Jun 2006
Location: Norway
Posts: 192
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 19
You misunderstood the question. I dont want to replace the absobtion on the backwall, i want to place a diffuser infront of it.
eXa is offline  
post #255 of 350 Old 01-29-2014, 12:37 AM - Thread Starter
Advanced Member
 
FoLLgoTT's Avatar
 
Join Date: Apr 2001
Location: Hannover, Germany
Posts: 517
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 90
Quote:
Originally Posted by eXa View Post

You misunderstood the question. I dont want to replace the absobtion on the backwall, i want to place a diffuser infront of it.

A friend of mine placed a diffuser similar to yours in front of his absorber. It still works. But I have not seen measurents from him without the diffuser. I think you just have to find out yourself.
mos6581 likes this.
FoLLgoTT is offline  
post #256 of 350 Old 01-29-2014, 05:29 AM
FOH
AVS Special Member
 
FOH's Avatar
 
Join Date: Apr 2010
Location: Midwest
Posts: 4,753
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked: 221
Quote:
Originally Posted by eXa View Post

Im curious. In a SBA setup, could you place diffusers on the back wall infront of the absorbtion material without interfering with it too much? If so, how big could the diffuser be?

You'll be fine.

Typically, the SBA LF wavelengths involved wouldn't be significantly impacted by such a diffusor. It's a prudent approach and common practice in studios and mastering rooms, ie., effective LF treatment faced with diffusion/scattering, redirection.

------------------------------------
Flat, Deep, Clean, Linear, and Loud
------------------------------------
Active 16.8kw, 7.3 system
(3)Seaton Cat12C up front, (4)QSC K8 sides/rears
(2)Seaton SubM-HP, (4)18" IB
FOH is offline  
post #257 of 350 Old 01-29-2014, 08:24 AM
AVS Special Member
 
coctostan's Avatar
 
Join Date: Oct 2005
Location: Indy
Posts: 1,960
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 132
Exa, although it will technically work, I doubt it will fit in a practical room. Between the exceptional depth needed to absorb the SBA, the depth needed to do an effective 1d diffusor, and the distance you need to sit from said diffusor it just isn't practical. I think Follo has 20"+ of absorption at the back of his room. Add on ~6" for the QRD's and the need to sit a minimum of 4' away from them.

A better solution would be very deep RPG BAD panel clone. It acts as low profile quasi-diffusor and allows you to sit much closer. It is basically just a random pattern of holes placed over the absorption. They do more of a controlled scatter and mitigate what would be overabsorption of the highs by scattering. RPG builds them up to 4" deep, but you could do it much deeper. You might also try a limp membrane in the middle of the panel to increase the effectiveness of the insulation depth. Oh and they are much easier and cheaper to build and can be covered in cloth for aesthetics.
eXa likes this.
coctostan is offline  
post #258 of 350 Old 01-29-2014, 11:24 AM
Member
 
mos6581's Avatar
 
Join Date: Oct 2011
Location: Norway
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by cuzed2 View Post

mos6581,

Very encouraging and impressive!
Am looking forward to how you are handling the rear wall, also how you will EQ those 8 drivers?
Do you have a build thread for this project?
The rear wall will be built as a false wall with about 20cm of air gap and 30cm of rockwool. I've done some simulation with a online porus absorber calculators, and with the locally available rockwool with a flow resistivity of 9000-11000 it's not much to gain by making a thicker wall. And i also have a door to consider. I'll also use some QRD diffusors on the rear wall.
I'll use the EQ on my Crown amplifiers. If the rear wall works as intended I'll only use a shelving filter to compensate for the roll of from the sealed subwoofers and two bands to reduce the remaining peaks related to the length nodes of 31 and 62hz.. I'll also run ARC on top of this to remove any smaller irregularities in the FR.
I don't have a build thread on avsforum just a small thread on a Norwegian forum.
Quote:
Originally Posted by eXa View Post

You misunderstood the question. I dont want to replace the absobtion on the backwall, i want to place a diffuser infront of it.
As some other people have answered, this should in theory not be a problem due to the wave length. To be one the safe side I would use diffusors made of EPS and not wood. At least this is what I'm going to do smile.gif
mos6581 is offline  
post #259 of 350 Old 01-29-2014, 01:41 PM
eXa
Member
 
eXa's Avatar
 
Join Date: Jun 2006
Location: Norway
Posts: 192
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 19
@Coctostan: Something like 6-7 feet from the back wall. Doesnt sound so bad. But you got some good points and alternatives.

Got my answer tho, some kind of diffuser on the back wall should be fine. smile.gif
eXa is offline  
post #260 of 350 Old 01-31-2014, 07:18 AM
Advanced Member
 
AudioJosh's Avatar
 
Join Date: Apr 2003
Location: Toronto
Posts: 645
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked: 99
*mildly related tangent*

The thing I like about threads like this is the focus on quality of bass rather than what seems typical on this forum of an obsession over quantity and a bass arms race. Not to be dismissive of that goal but rarely does it seem that much attention is paid of quality and tackling room modes. Granted if you are focused on max SPL below the primary mode, say 40hz, down to single digits then modes aren't the major factor but really the midbass region 40-200hz is a very critical region for quality audio reproduction and where the room matters.

DBA/SBA aren't the only solutions. HK"s 4 middle walls solution, Geddes' spatial averaging solution, etc are also very good solutions although maybe a bit harder to setup originally as it requires measurement and iterations. I'd just wished more bass threads spent more time focusing on the quality aspect in addition to the quantity.

*tangent off*
maxmercy likes this.

JoshK on most other audio forums
Quantity only when quality is ensured.
AudioJosh is offline  
post #261 of 350 Old 02-02-2014, 07:01 AM
AVS Special Member
 
coctostan's Avatar
 
Join Date: Oct 2005
Location: Indy
Posts: 1,960
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 132
Josh-

I agree completely. In fact there are many cases when people keep adding capacity when it is a response issue they really need to address.
Quote:
Originally Posted by eXa View Post

@Coctostan: Something like 6-7 feet from the back wall. Doesnt sound so bad. But you got some good points and alternatives.

Got my answer tho, some kind of diffuser on the back wall should be fine. smile.gif

You have 6-7ft from the rear wall to the nearest listening positions? Is that with or without that 2' of absorption and 6-8" of diffusion? It depends on the diffusor used, but typically time based diffusion really needs you to sit a good distance away or the effect can actually be detrimental. How far depends on the diffusor design.

The BAD panels eliminate the depth of the QRD and also allow you to sit closer due to the fact that they are amplitude based.

They also allow frequencies under 1khz to be absorbed by the insulation behind the panel whereas a typical QRD with solid backing will act as a hard surface over a bandwidth from about 300hz to 1khz before doings job (this depends on design and materials). It is much more difficult to integrate a 1d or 2d diffuser with bass trapping behind it.
eXa likes this.
coctostan is offline  
post #262 of 350 Old 02-13-2014, 06:40 PM
eXa
Member
 
eXa's Avatar
 
Join Date: Jun 2006
Location: Norway
Posts: 192
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 19
Bit slow to answer.

I have nothing atm, well. a livingroom setup wich is not at all suited for DBA/SBA. This is more of a learnig process.
But with a dedicated room with say 20'ish length (my livingroom now is 21.5') i dont see any problems in sitting 7-8feet from the back wall, even if i move the front wall 2feet out to hide speakers and such. Dont think i would want to sit any closer anyways. That is actually very close to my current situation (i have the the 100" screen and speakers almost 3' into the room because of all the windows on the front wall.)
I think i modeled a 1d diffuser to work down in the 500hz range for my current livingroom, no point to go lower than that because of distance and depth. But IF you should sit abit closer, it isnt like it stops working at all, just not as good.

But yeah, again. Very good alternative. Sounds easier and got the benefit of beeing able to sit closer. So probably the best solution in a SBA setups since you already got alot of absorbtion there anyways.
Only drawback is that i like the looks of a big 1d diffuser better tongue.gif But looks is not a big priority in a dedicated room anywas so moot point. (in my opinion anyways)

Edit: Actually, now you got me thinking about 2 RPG BAD panels on my back wall (in my living room). Seems much easier and cheaper to build than 2 big 1D diffusers. Need 2 big ones 1400-1500mm wide, because there is a opening to the kitchen in the middle. Gonna read more about them (found some on gearslutz)

Edit2: When i think about it, 1200x1200mm is much more sensible since standard sheets here in Norway is 1220x2440mm. Would only need 1 sheet for the 2 of them smile.gif
eXa is offline  
post #263 of 350 Old 02-13-2014, 10:34 PM
Member
 
Adhoc1's Avatar
 
Join Date: Apr 2009
Posts: 39
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 13
I don’t know where you live in Norway but Optifusser may be an option for you. Very good performance and cheap for the size and can also be combined with a panel absorber behind for a very low mode problem frequency. Info: http://www.resonatorstockholm.com/Optiffuser/Optiffuser_Manual.pdf Size 2,88 m², 4 pcs, each 1200x600x220 mm, costs about 2800 Sw. kronor (about USD 412:- ) at Emusic here: http://www.emusic.se/Product/17813/Resonator-Stockholm-Optiffuser. (If I had had room for it, I would have gone for that one instead of the BADs I made, as these take considerable time to DIY.)

End of OT.rolleyes.gif
eXa likes this.
Adhoc1 is offline  
post #264 of 350 Old 02-14-2014, 12:13 AM
eXa
Member
 
eXa's Avatar
 
Join Date: Jun 2006
Location: Norway
Posts: 192
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 19
That is actually quite good to know. The price is really good. Ive calculated the price in wood for making some 1D diffuser that would fit for me... and i couldnt do a diffuser that big for the price they are asking smile.gif And that isnt taking in account all the hours it would take to build it.
Bookmarked. Thank you.
eXa is offline  
post #265 of 350 Old 02-14-2014, 07:43 AM - Thread Starter
Advanced Member
 
FoLLgoTT's Avatar
 
Join Date: Apr 2001
Location: Hannover, Germany
Posts: 517
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 90
Quote:
Originally Posted by Adhoc1 View Post

I don’t know where you live in Norway but Optifusser may be an option for you. Very good performance and cheap for the size and can also be combined with a panel absorber behind for a very low mode problem frequency. Info: http://www.resonatorstockholm.com/Optiffuser/Optiffuser_Manual.pdf Size 2,88 m², 4 pcs, each 1200x600x220 mm, costs about 2800 Sw. kronor (about USD 412:- ) at Emusic here: http://www.emusic.se/Product/17813/Resonator-Stockholm-Optiffuser. (If I had had room for it, I would have gone for that one instead of the BADs I made, as these take considerable time to DIY.)

Thank you very much for this hint! These diffusers are cheaper than Vicoustic's Trap Fuser and there is a sales discount for large numbers. Maybe I should start a group buy to Germany... smile.gifrolleyes.gif
FoLLgoTT is offline  
post #266 of 350 Old 02-14-2014, 02:13 PM
Member
 
Adhoc1's Avatar
 
Join Date: Apr 2009
Posts: 39
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 13
I guess you already know Nils (?); the guy behind these diffusers is the same Jens who has been active in your SBA thread on Gear Slutz. (In my view, one of the better advising acousticians at GS.) The used Styrofoam is quite tough and sturdy, not like the fragile light weight stuff you find at the lumber yard for common insulation purposes.

Personally I’m not too fond of the aesthetics so I would hide the diffusers behind a perforated or stretched metal sheet (open area should be above 65% not to degrade the diffusive properties), like here behind the sofa and part of the side walls: http://www.component.se/forum/index.php?showtopic=12725&page=24#entry188396
Adhoc1 is offline  
post #267 of 350 Old 03-19-2014, 02:12 PM
Newbie
 
Klinkenborg's Avatar
 
Join Date: Mar 2014
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10

Hi All,

 

First post here so be gentle!  I am quite taken with the idea of the DBA, however I cannot get my head around its transient response.  Imagine if you will a transient sound played by the front array.  For the sake of argument let's say the 'distance' between arrays is 15ms and the seating position is 2/3 of the room length from the front array.  Said transient will arrive at the ears after 10ms, however the delayed rear signal will take 20ms (15ms added delay plus 5ms from rear array to ears).  Does this have any noticeable effect?  Clearly this problem does not occur with the SBA, so is the latter setup superior?

 

Cheers, Carl Klinkenborg.

Klinkenborg is offline  
post #268 of 350 Old 03-19-2014, 03:08 PM
AVS Special Member
 
markus767's Avatar
 
Join Date: Apr 2009
Posts: 6,776
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1848 Post(s)
Liked: 668
^
The delayed signal of the back wall array "cancels" the signal from the front system when it hits the back wall.

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
markus767 is offline  
post #269 of 350 Old 03-19-2014, 10:03 PM
Advanced Member
 
pitviper33's Avatar
 
Join Date: Sep 2011
Location: Eastern TN
Posts: 637
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 235 Post(s)
Liked: 104
Quote:
Originally Posted by Klinkenborg View Post

Hi All,

First post here so be gentle!  I am quite taken with the idea of the DBA, however I cannot get my head around its transient response.  Imagine if you will a transient sound played by the front array.  For the sake of argument let's say the 'distance' between arrays is 15ms and the seating position is 2/3 of the room length from the front array.  Said transient will arrive at the ears after 10ms, however the delayed rear signal will take 20ms (15ms added delay plus 5ms from rear array to ears).  Does this have any noticeable effect?  Clearly this problem does not occur with the SBA, so is the latter setup superior?

Cheers, Carl Klinkenborg.
The idea is that the action of the rear array is the exact inverse of the pressure wave arriving from the front array. Therefore, because the resultant pressure is zero, there is no wave propagation from the rear array toward your ears. You should perceive nothing at 20ms in your example. It's the same kind of idea as noise canceling headphones. You can't detect the inverse signal they're playing, because its energy has been completely cancelled by the incoming wave.
pitviper33 is offline  
post #270 of 350 Old 03-20-2014, 12:42 AM
Newbie
 
Klinkenborg's Avatar
 
Join Date: Mar 2014
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by pitviper33 View Post


The idea is that the action of the rear array is the exact inverse of the pressure wave arriving from the front array. Therefore, because the resultant pressure is zero, there is no wave propagation from the rear array toward your ears. You should perceive nothing at 20ms in your example. It's the same kind of idea as noise canceling headphones. You can't detect the inverse signal they're playing, because its energy has been completely cancelled by the incoming wave.

Hi Pit,

 

Thanks for the explanation; I understood this was the theory but was interested in the practical application - just how effective is this theoretical cancellation compared with a 'total' absorber.  I am lucky enough to be able to spare the metre-thick space I would lose with an SBA so was keen to learn which system is actually superior, regardles of cost and complexity,

 

Cheers, Carl.

Klinkenborg is offline  
Sponsored Links
Advertisement
 
Reply DIY Speakers and Subs

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off