Anyone have experience with or with using true pressure traps?

I am preparing to build a two channel listening room in my basement. Planned dimensions are 17’X23’X10’. Perfect chance to get it right since it is to be built from scratch. One chance if you will.

i have some experience with velocity traps (absorption), enough to know that when using typical absorption products, it is nearly impossible to effectively address room bass nodes without creating an acoustically dead room since fiberglass and rock wool traps are exceptionally efficient at absorbing mid and high frequencies and exceptionally inefficient at absorbing low and even mid-bass frequencies.

After checking out several companies online that specialize in room treatment, Acoustic Fields ( stood out to me because they design and build pressure traps that precisely target specific frequencies (vs the broad-band behavior of velocity/absorptive traps) based on mathematical modeling identifying exactly where and what frequencies of acoustic anomalies will occur in a specific room and matching frequency-specific pressure traps in the exact room locations that reduce/eliminate problem nodes at the listening position without affecting non-target frequencies as velocity/absorptive traps do.

This approach promises to get quite expensive. I am wondering if anyone here has any experience with Acoustic Fields (or installing/using pressure traps) that would provide helpful input regarding their experiences.



Get a mic and REW and do some measurements in the space.

Are you thinking of the mass loaded membrane traps?
Those are somewhat modellable, but I think you need to have the target freq, and then tune it by adding or taking away a bit of mass at the end… much like a passive radiator.

There are also the round bass traps, which could be added later, as well as active bass “traps”. But starting with the in-wall resonant ones makes a lot of sense.

Once you know the low frequency decay, then just treat the higher freqs so that their delay is similar. (I.e. don’t go overboard with super short ring down times for high frequencies, if the low notes are taking forever to decay.)

The resonant freq on the various places will likely be different along the walls… !

Lowest in corners, then long walls, then short walls.

 Starting from scratch will give you the possibilities that most of us won't have. I couldn't be more interested in the outcome.

  It does remind me of a product though that didn't go far for room correction. Must have been a financial thing because it made sense to me. I remember some company that used correction in the form of an anti-bass wave being used to cancel out the nodes in the room. Basically a sample was taken during every moment of the music and a microphone and amplifier/speaker combination produced the anti-wave. Seems this system was placed in the corner of a room. Didn't hear much more about it after its inception. 

I am also about to build a dedicated 2 channel listening room, about 31 x 23 x 14. I am wary of  building a lot of treatments into the actual structure that I cannot reverse. So, instead, I am planning to use the ASC ISO wall construction methods and then add treatments inside the finished space as needed based upon listening and measurements. Consulting with ASC.  I also have many Stillpoints Apertures, which I will try to incorporate if possible and appropriate. Best of luck!

I participated in a call with Dennis this afternoon. He was friendly and helpful and came across to me as one who knows what he is talking about. The bottom line is that he offered his room design services for a substantial fee (which is completely credited toward a subsequent purchase of goods) and suggested that I go the DIY route, buying only the carbon and foam from him, due to my limited budget. It appears it will take a lot of carbon to build the complement of pressure traps (around 70!) needed to completely treat a room this size (17’X23’X10.5’).

Two things look to be a problem: 1) he said he is backlogged 2-3 months for design services and 2) the cost. I could possibly swing (at the high side of my budget) the number he quoted if the pressure traps were turnkey, but adding labor (and the cost of wood) for my carpenter to build 70 of the pressure traps would make the cost way beyond my means.

@arsh I briefly reviewed the description of the ASC ISO system on their website and it appears that it primarily intended for soundproofing. That is not a concern for me since the new room will be the only room in the basement and the exterior walls are cinder block and mostly underground. I am 100% focused on optimizing the sound quality inside the room itself. Did I misunderstand the ASC ISO system’s benefits? BTW I really like the concept of the Stillpoint Aperatures and hope to work four into my room budget.

@4krowme I recall there was a product from Billy Bags some time ago that used a microphone and an amplified bass speaker wired out of phase that was hung in a corner from the ceiling to cancel room bass nodes. I thought it was interesting but it was long discontinued by the time I discovered it. Would that be what you are remembering?

Dlcockrum, here you go...


"The Iso-Wall construction technique solves the three main problems with listening rooms: 1) it greatly reduces wall shudder; 2) prevents sound inside the listening room from getting out; and 3) absorbs excess bass energy by virtue of the flexible walls, turning them into giant membrane bass traps."