Thanks Bryan. I already have my Tri traps.Just wondering why FRK was not used on the Tri traps when virtually all advise given to people making their own bass traps was to include FRK. Including advise from Glenn and possibly yourself too. Given that Tri Traps are made to go in corners, it seems strange that FRK was not as standard with Tri Traps in particular. I don't doubt that there is a good reason, but just curious as I'm trying to learn about this stuff.