What kind of Bass Trap is this?

[Gammon2018]

Hi all - so I was visiting a friend's studio this week and asked him about the bass traps, which were professionally designed around 20 years ago. He showed me the plan, which I've included a picture of here. Does anyone know what kind of bass trap this is, or what the benefits would be to this kind of bass trap as opposed to just cutting 703 into triangles and stacking it all the way to the top? Thanks in advance!

[Gregwor]

That is a tuned membrane trap.

Greg

[JasonFoi]

The membrane creates a resonant cavity which will cause the trap to absorb deeper than just the oc703, but with a narrower Q. Also, due to the high flow resistivity of oc703 it doesnt make sense to me to use it more than 8" thick by itself. You can model any trap you are curious about using the following calculators


http://www.acousticmodelling.com/porous.php


http://www.acousticmodelling.com/multi.php


The following thread has lots of GFR data for commnly used materials. Oc703 is 16,000 or 23,000 depending on where you look.


https://www.gearslutz.com/board/studio- ... mbers.html