Hi folks,
My first post here and I'd first like to thank Ethan, and all the contributors for their advice and expertise. I'm a recording/mixing engineer based in Brooklyn, NY, and have recently been more involved in project studio design. During the design stage of recent project a question raised concerning bass trapping options, and I was led to this forum. I've seen a few "hanger" type trap designs that utilize vertical ceiling/floor space for hanging insulation panels, but because of the general non directional nature of bass frequencies, I wondered if a horizontal version of this approach is feasible by modifying a raised floor platform. The platform I'm considering is roughly 7' (w) x 10' (l) x 10"(h) and would be built in a corner of a 13' (w) x 21' (l) x 9' (h) room. The platform's purpose is basically to provide a space for a couch, but I wondered if "porting" the front of the platform (as in some type of air access to the inner platform chambers between joists), and arranging rigid insulation within the chambers would create a bass trap. Has anyone ever come across anything like this? I'm curious, and would be grateful for your insights. Thanks alot,
Jon Evans

Hi Jon,

Welcome to the forum.

I don't have much experience with Helmholtz type absorbers. I have heard of people building bass traps into furniture and platforms etc. This is common in home theaters, where the riser for the rear row of seats does double-duty as a bass trap. I can't imagine that could serve as the only bass trap in a room though. If for no other reason, a riser may have a large surface area parallel to the floor, but will have very little surface in either of the other two planes.

> arranging rigid insulation within the chambers would create a bass trap <

You'd probably get similar results just by filling it with fluffy insulation, which is also cheaper. I wish I had more to offer, but I can at least point you to a place where hanger absorbers and Helmholtz traps are discussed by folks more knowledgable than me:

http://www.johnlsayers.com/phpBB2/index.php

--Ethan

Thanks for the reply Ethan,
I wasn't aware this was a practice in home theaters, and yes it would seem sensible to have other treatments for bass as well. I had planned on it myself in the design I'm working on, and was curious as to what contributions, positive or negative, an in floor unit would make. As for the Sayers site, I've been lurking around there for quite some time, and have found some great folks, and info there. Thanks for the link!
All the best,
Jon E.