Two subs or To trap

stanly.joseph

stanly.joseph

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May 31, 2015
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Hey guys

I'm told that I need to do some bass trapping in my room to remedy certain acoustic problems but I also watched a YouTube video by audioholics stating that bass problems can be rectified by adding a second sub.

Is that accurate? And If I decide to add a second sub, does it need to be of equal size and caliber to the first sub?

I currently own have the B&W ASW855.


Thanks much guys. Appreciate it.
 
stanly.joseph said:
Hey guys

I'm told that I need to do some bass trapping in my room to remedy certain acoustic problems but I also watched a YouTube video by audioholics stating that bass problems can be rectified by adding a second sub.

Is that accurate? And If I decide to add a second sub, does it need to be of equal size and caliber to the first sub?

I currently own have the B&W ASW855.


Thanks much guys. Appreciate it.
Click to expand...


Two subs will certainly balance out a room better than a single. Both subs should be the same, yes.

Room corners generally benefit with traps or similar treatment regardless.
 
Steve said:
Two subs will certainly balance out a room better than a single. Both subs should be the same, yes.

Room corners generally benefit with traps or similar treatment regardless.
Click to expand...

So I should just treat the room first and see how it sounds? I don't think I'll be able to find the exact same sub. Its a pretty old model.

I was thinking of the SVS SB13 ultra sub.
 
If you have an old thin foam mattress, you could roll that into a tube and experiment with positioning in various parts of the room beginning with corners. Similarly stack a pile of pillows in the corners.

This would be a good starting point in understanding and potentially identifying peculiarities of your room, where standing wave reflections are originating causing frequency cancellations and peaks.
 
My $0.02 is that you want both bass traps and multiple subs. The subs improve the peaks and nulls (ideally you have 4 with different damping factors, sizes, etc.), and the bass traps help the waterfall decay. Even with both it's still a struggle to get a really smooth response, but the faster decay makes my ears "hear" smoother sound, and the subs reduced peaks and valleys from ~20 dB range to <~10 dB.
 
stanly.joseph said:
So I should just treat the room first and see how it sounds? I don't think I'll be able to find the exact same sub. Its a pretty old model.

I was thinking of the SVS SB13 ultra sub.
Click to expand...

Yes, definitely treat the room first. Here is a recent experience of mine:

http://www.whatsbestforum.com/showthread.php?20189-ASC-tube-traps-effect-of-their-absence

I am also thinking about buying Isothermal Traps,

http://www.acousticsciences.com/products/isothermal-tubetrap

for the rear wall (behind my listening seat) in order to prevent deep bass bounce and thus having even better deep bass.

I have a single sub. I used to have two subs, but at the time it didn't make much difference. Room treatment is far more important, but perhaps multiple subs are the icing on the cake. Proper room treatment is probably cheaper too.
 
FlexibleAudio said:
Talk to Nyal at Acoustic Frontiers. He da man.
Click to expand...
I haven't done it yet but Nyal told me most speakers can benefit from subwoofers. But the main speakers/subs must be properly tuned using an external crossover that will allow control of both. Paraphrasing Nyal; properly integrated subs improve the transition from bass to midrange resulting in better articulation in that area.

Nyal is an excellent acoustician - I'm very pleased with my Nyal designed dedicated media room:)
 
stanly.joseph said:
So I should just treat the room first and see how it sounds? I don't think I'll be able to find the exact same sub. Its a pretty old model.

I was thinking of the SVS SB13 ultra sub.
Click to expand...
You don't need to match subs. Check out this article on Swarm subwoofer approach--basically you want different subs (or at least different cut-off frequencies, gain, volume, phase, and damping), with different sizes/types being advantageous to randomize the peaks and nulls (peaks are really hard to address even with trapping, so constructive interference can be your friend).
https://drive.google.com/file/d/0BxgUOGOB5HbfR0JTRF9XZjkyUms/view?pli=1
 
Gosh this is getting more confusing! Have anyone used this software measurement kit?

47e2b2e2f275dd7a1d1fb1b3e2aa6503.jpg
 
stanly.joseph said:
Gosh this is getting more confusing! Have anyone used this software measurement kit?
Click to expand...
I use something similar--you need some way to measure room response. I use REW free-ware and a used calibrated mic. It's pretty easy, but will take a few sessions to get the hang of it. I found it enlightening (if depressing) to see what my baseline performance was prior to treatments and subs.
 
LenWhite said:
I haven't done it yet but Nyal told me most speakers can benefit from subwoofers. But the main speakers/subs must be properly tuned using an external crossover that will allow control of both. Paraphrasing Nyal; properly integrated subs improve the transition from bass to midrange resulting in better articulation in that area.

Nyal is an excellent acoustician - I'm very pleased with my Nyal designed dedicated media room:)
Click to expand...

That is correct but crossover is only the beginning if the room is not properly designed. Room correction and time alignment are also critical to integrate the subs properly. The problem then is managing your analog sources. Time alignment (phase) and room correction get done in DSP. I opted for maxing out room treatments via Nyal as the first step. If the bass is not to my liking I may add subs and an analog crossover (like the Pass XVR-1) but time and room correction are out for me given my love of vinyl. That said, with a good room design, the timing and phase alignment can be handled by sub placement (assuming the room's design has minimized modes). Room correction is also less important if the modes are dealt with in the design phase.
 
ACHiPo said:
I use something similar--you need some way to measure room response. I use REW free-ware and a used calibrated mic. It's pretty easy, but will take a few sessions to get the hang of it. I found it enlightening (if depressing) to see what my baseline performance was prior to treatments and subs.
Click to expand...

What's the difference between the below room analyzer and let's say the Audyssey XT32 or Anthem room correction?

49e835077c4e3c88b5fdddf6bd30de8c.jpg
 
Sure the Audyssey XT32 will give you a compensation picture but it is has its own biases. For one it is heavy on everything above 5kHz.
 
I ordered the XTZ room analyzer. Might need some help interpreting the results since I'm new at this stuff.
 
stanly.joseph said:
I ordered the XTZ room analyzer. Might need some help interpreting the results since I'm new at this stuff.
Click to expand...
Contact me and I'll help if I can. I do not use room correction, which Audyssey, Dirac, etc. employ, but a mic and impulse and spectrum analysis software is your friend.

AC
 
Here's a link to the REW download. While there's no absolute standard, this app seems to be pretty widely used which makes getting help interpreting results easier.

http://www.roomeqwizard.com/
 
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