My Studio Is DEAD

[Nordenstam]

General rule is to keep diffusers at 3 times their base wavelength. That's 1 meter for a 4" deep diffuser. Building such shallow ones in 2D should work fine in that room.

[Glenn Kuras]

You can put them on the back wall, side walls behind you and ceiling behind you. For the back wall though I still would mix it up and put absorption and diffusion. See the following as a guide.
GIK Acoustics: Room Setup

[Ethan Winer]

Originally Posted by morebutter

I am already looking into building QRD's for the ceiling ('cloud')

I prefer absorption at the side-wall and ceiling reflection points. With a 10-foot ceiling diffusion might be okay, but you'll probably do best with diffusors everywhere except reflection points. I had great success in a small room using lots of diffusion as shown in this video:

Hearing is Believing

--Ethan

[Nordenstam]

Originally Posted by Ethan Winer

you'll probably do best with diffusors everywhere except reflection points.

Sage advice!

Had a try at diffusion at first reflection points. Was glad to go back to absorption there.

Generally, you want diffusion where it'll be little noticeable, where it affects the tail of the reverb. Subtle sweetness!

[Ethan Winer]

Originally Posted by Lupo

Had a try at diffusion at first reflection points. Was glad to go back to absorption there.

Just curious, how wide is the room? When I tried diffusion at the side-wall reflection points in my living room (16 feet wide), the sound was noticeably worse than with absorption. But I've never compared absorption versus diffusion in a very wide room, and I wonder if it might sound better than in a smaller room.

--Ethan

[takman]

just out of curiosity...what are the walls and ceiling made out of? sheetrock?

[Nordenstam]

Ethan; The room is thinner, four meter on the sides, with 30cm deep absorbing patches semipermanently installed on the side walls. The diffusers was placed outside of those so it was a little over three meter total. Way obvious! Probably indeed a different scenario in bigger rooms.

[morebutter]

Okay thanks for the advice. I was first thinking of putting the diffusors at the first reflection points, so I'm glad I asked; it makes sense to not put them there.

[DanDan]

Not all Dead is bad. Music often sounds awful in treated rooms. It is very likely that your treatment has removed all sorts of honks and booms, which of course could also be called 'warmth' . This leaves a very clear but harsh sound. If you measure your frequency response, you may find it to be substantially flat in the mid to high frequencies. I am firmly of the opinion that such a response is totally wrong for our purposes, e.g. for mixing.
Bruel and Kjaer used to sell a test record some time ago.
It had a recommended listening curve which went from approx +3dB at 100 Hz to -3dB at HF. Quite a slope you might think. However, they didn't just make that up. There was reason and research. It's not just B and K and me either. Check out Understanding RTA at studiotips - tips on studio design, acoustics, and wiring or many other sources. Turn down your tweeters.
DD

[jhbrandt]

morebutter, listen to Ethan. He knows what he's talking about.. or call an acoustics consultant.

IMHO a resonant type bass traps with damping in the rear corners would take care of your humps and bumps better than totally killing the room... put some of your home-made diffusers on the back wall.

I have a QRD calculator in Excel spreadsheet and others for download and several other good articles on my web site(s). Please check out the link to Acoustic Myths on the javakustik site.

Your room is approximately 1820 cu. ft. and with the dimensions given you have minor modal issues at 50 hz and 173~187 Hz. Never mind the 50Hz but the 173~187Hz can be very annoying.

Suggestion: Take down most of the rigid fiberglass and acoustical cotton that is NOT in the Reflection zone. You can use what you take down to make bass traps in the corners of the room. Use diffusion on the back wall and possibly on the back ceiling. You can checker-board the absorption panels to actually increase their effectiveness while maintaining some semblance of 'natural' sound in the room.

Tip: have a friend help you with a mirror by placing it on the walls & ceiling... until you (sitting in the mix position or listening position) can see the speakers. At that point (where the mirror was when you saw the speakers) place absorptive material thereby creating a reflection-free-zone.

I believe that a good mix room, recording room, or simply listening room should be so enjoyable to be in that you would want to work 12 hours a day in there.