bass traps

[antispatula]

So I've been trying to learn about them. I want to build my own. I read somehwere that you want to make a frame up against your wall, mount rigid fiberglass so that there is air on each side of it, and then nail a piece of plywood on it. I don't get it, wouldn't plywood reflect all the sound? Are you supposed to mount more foam on the outside? And should bass traps be everywhere, or just in corners? Wouldn't bass traps no have plywood on the fronts? Thanks a bunch.

[Ethan Winer]

> I don't get it, wouldn't plywood reflect all the sound? <

Not necessarily at low frequencies. See my Acoustics FAQ:

www.ethanwiner.com/acoustics.html

Also see the link near the top, in the 3rd paragraph, to my wood panel bass traps article from Electronic Musician magazine.

--Ethan

[punkin]

Ethan,

I've looked at your postings many times and I just want to say thanks for the advice and information. While I'm not considering building one of these traps but something about those diagrams/drawings havel always puzzled me.

The bass traps show that there is a 1/4" plywood front and that the frame should be sealed with calking. Your diagrams give a look down or look up view but don't show that the ends are capped off or is that because they extend all the way from the floor to the ceiling and would be capped off by that fact?. Should they be completely sealed? Or am I missing something here...perhaps the traps are to be open at the top and bottom?

Just curious...thanks!

[antispatula]

here's an overhead view.
would this design work for the corners of my room?

[Ethan Winer]

punk,

> Should they be completely sealed? Or am I missing something <

Yes the traps must be sealed, as explained in the article. Although the top and bottom caps are not shown in the drawings, I'm pretty sure the text makes it clear that those caps are needed.

--Ethan

[punkin]

My bad...must have missed that bit of info. . Again, thanks...there's a science I'm fascinated by.