Originally Posted by Oli_W ➡️

Thank you for every pitching in!

This isn't my first-stop acoustic treatment- I have a lot of broadband absorption already, and some limp mass resonators to help deal with the length mode. The width mode is the one I notice at the listening position. I have membrane material and a fair bit of rock wool remaining, so am going to use it up.

It seems that people's concern is that putting the porous absorption in front of limp mass, even with the air gap, might affect the Q or operating frequency of the trap. Therefore I'm going to try with just the membranes at first, get them positioned for maximum affect, and then test out whether or not the porous absorber makes it ineffective. This is instead of building the membrane and porous absorber as a neat-looking combo, covered in fabric, and hoping for the best.

Cheers!