Seeking suggestions for home-made diffusion.

[Dougtune]

I'm a musician and I use my basement for practice/rehearsals/recording. I play trumpet and record acoustic instruments, and a dead room is NOT what I want. I would like it live but not bright or harsh.

The room is roughly 21'3" X 14'3" with a 7'2" drop (acoustic tile) ceiling. The floor is 1/2 hardwood and 1/2 carpet. The walls are drywall with wallpaper. I know it's possible for a room this size to have some reverb, as in un-finished basements, but this room has no reverb, which makes horn-playing a drag. I'm considering some Auralex T'Fusors for the ceiling and some kind of diffusion for the walls, which are now a bit slappy.
I thought wall diffusion might also help increase the sense of reverb.

Any suggestions for effective home-made diffusors? I can work with wood.
Thanks, Doug

[knightfly]

There are a few ways of building diffusors, like using short scraps of 2x lumber set on end and glued to a plywood back, or more involved such as building actual prime root diffusors with calculated well depths, etc - but your main problem is most likely 6 feet too low a ceiling, and the half carpeted floor.

Your room DOES have a reverb component, but as small as the room is, when you're actually PLAYING your horn, by the time the noise in your head from the actual note goes away, the reverb of the room is already gone.

The "slappy" walls are from parallel surfaces - you could improve on that without deadening the room further by building some of John's slant-faced wall units, which are also slat absorbers - the wall units are shown here -

http://www.johnlsayers.com/HR/index1.htm

If you build these, you should calculate the slat/slot configuration using the calculator found here -

http://www.saecollege.de/reference_mate ... mholtz.xls

and, I would do a modal analysis of your room dimensions (the ceiling height, for most types of "drop" ceilings, would be the dimension from floor to the "hard" ceiling, or the solid construction above your drop ceiling. There is a calculator for that here (requires Excel on your computer, though) -

http://www.studiotips.com/tools/MODESv2p.zip

This calculator has some basic directions/suggestions on the first page, but if you need more info I can help some. If I get lost on your questions, the guy who wrote this is chief acoustics engineer for Auralex and a member here, so help is available one way or another.

Anyway, I would do a modal analysis of your room using modesV2p, to determine which frequencies will have to be treated - then, you could use the AVERAGE depth of John's wall units as the "depth from wall" in John's helmholz calculator, and work out a slat/slot width combination that would help tame those frequencies.

The advantage of using those wall units - that "slappy" stuff will go away if you use enough of them, only has to be on one wall of each pair - They won't reduce reverb like some of the other alternative treatments for slap echo (flutter echo) - and you won't have to build actual walls that aren't parallel to solve those problems.

It's hard to diagnose these things by remote control sometimes, but those are the things I would try from your description... Steve