Acoustic treatment


I want to build my own bass traps and was wondering if there are any other alternatives to fiberglass and rokwool. Foam is not a consideration as I don't believe it has the necessary qualities for absorption. I have heard of cotton batting, does anyone have experience with this material. The idea of fiberglass makes me itch just thinking about it, but I'm resigned to using it or rokwool if that's all I have.  Please make suggestions and let me know your experiences.

Thanks
Mike
zardozmike
@noble100, Correction, does a DBA system, or a SBA too, sound better in a treated room compared to an untreated room?

And... what is a DBA?  
b_limo: "@noble100, Correction, does a DBA system, or a SBA too, sound better in a treated room compared to an untreated room?"

Hello b_limo,

     DBA is an initialism for distributed bass array.

     My 4-sub DBA system is in an untreated room and functions very well.  I can't imagine how any bass room treatments would be beneficial.  The DBA concept works best when bass soundwaves are allowed to freely reflect off room boundaries, I think any room bass treatments that would impede these bass soundwave reflections likely would also impede the effectiveness of the DBA system.

     Sorry, I don't know what an SBA is.

Tim
I now have 14 absorbers positioned throughout my listening room/ living room "not ceiling yet" and all I can say is I'm truly a believer.

They are all 4' x 2' x6". 
Lots of misinformation in this thread...

multiple subs do not magically eliminate bass decay. Bass traps are meant to absorb the bass resonance and reflections building up and coloring the initial signal. Having multiple LF source cannot address the bass decay  issue. Without enough LF absorbtion via bass traps, the bass will sound slow, lacking in attack and transient.

Multiple subwoofer will allow the user to have a flat FR easily, but it doesnt at all adress the biggest problem which is bass resonance that can be easily measured via ETC measurements.

Bass traps should be very large, made of Roxul or Owens fiberglass, ideally at least 12 inch thick, floor to ceiling, placed in as many corner possible.



mijostyn:
"Boy are you out to lunch on this one Tim. It is not what you hear. It is about what you feel. I would bet that you have never played with a system in which you can control phase and arrival times which is why you have this rather flaky opinion. This makes a major difference in the realism of the system. Just wire one sub out of phase and see what you get. I've got news for you. You have to be in phase the entire cross over region. If you are 1/2 wavelength out of time you have one sub wired backwards. This would be the kind of biased unacceptable opinion you swarm guys would come up with. If you think the bass you have now is good, you have a long way to go. "

Hello mijostyn,

     Sorry I'm so late getting back to you, we went out for lunch and we waited about 3 months for our food! So, I literally have been out to lunch.
      I feel like you have a poor understanding in general about how and why the Swarm 4-sub distributed bass array (DBA) concept works so exceptionally well.  Here's a summary of some key DBA concept info to help you grasp it:

-Phase is important and the Swarm's phase can be continuously adjusted for the 4 subs as a group on the amp/control unit. Also, during the setup process one of the final steps is to reverse the phase on each sub individually to make sure the bass doesn't sound better with one of the sub's phase reversed.  
-The fact is that the very long bass soundwaves behave very differently than the much shorter midrange and treble soundwaves in typical domestic rooms.
-This makes sense since a full-cycle 20 Hz deep bass soundwave is about 56' long while a 20,000 Hz full-cycle high treble soundwave is a fraction of an inch long.
- It's been proven that we don't even hear a deep bass frequency under 80 Hz until the full duty cycle of the frequency sound wave has been released into the room, our ears have transmitted the details of the full-cycle deep bass soundwave to the brain and our brain processes this info as the perception of a deep bass tone present in the room. 
-In other words, we cannot detect the presence of bass under 80 Hz from less than one full wavelength. 
-We also need to hear multiple full wavelengths of bass under 80 Hz before we can detect pitch and volume.  A 56 foot 20 Hz sound wave released into a normal sized room means it is going to bounce or reflect at least once before the entire duty cycle is detected and be able to be heard at the listening position. We also need to detect multiple cycles at the listening position to determine pitch and volume.
-This implies that relatively small timing differences - 'small' relative to the wavelengths in the under 80 Hz bass region - are not going to make an audible difference in and of themselves. 
-The time domain aspect, or the timing of bass sound waves reaching the listening position, is of much less importance for deep bass frequencies than it is for mid-range and treble frequencies.  We're actually not very sensitive to arrival time in the bass region.
-There's no requirement for the correct timing so that the sound from each bass driver hits the listening position at exactly the same time like there is with the midrange and treble drivers.    
-The 4-sub DBA concept works so well due to creating numerous well dispersed additional bass room modes (bass peaks and dips) at various frequencies in the room. 
-The psychoacoustics identified principle of our brains processing these numerous varied bass room modes by averaging them out results in the perception of the bass as accurate, detailed, fast, smooth and natural.
-This is properly described as controlling the speakers to correct abnormalities of the speaker/room system, not as "room control".



Tim