My DIY absorbers were a weak effort (i.e., not terribly absorbent) and still worked well at the first reflection. From the web description, I think the 2" would work as well as the 4" for you primary goal here, which is to deaden the reflection over 500hz. And the 2" would be much easier to place.


Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire