[jhill]

Thanks takman for the websites. Good information!

I'm still really hoping one of you acoustic guru's happen upon this thread...

So once again to review (for anyone who's interested), we're having issues with bass volume & intelligibility in my band member's home studio. Bass player keeps turning up because he can't tell what he's playing, guitars player's wife gets upset that the kids can't sleep. The studio is a room inside a room, all walls & ceiling are 5/8" QuietRock/ 5/8" drywall/ 5/8" Quietrock Sandwiched (no air gap). The ceiling is attached to the floor joists. All vents are outside the room, and still lined with auralex. 2 doors on each doorway, each lined with mass-loaded vinyl. Room is about 25x20x7.5'. Carpet floors.

I have noticed some significant standing waves around 150-200Hz, though I didn't have a tone generator last time I was there. He has about 50% of the room covered with 2" auralex, and 8 total lenrd bass traps in the corners...(basically nothing)

QUESTION: Could moderate bass trapping (such as suggested below) decrease enough of the standing wave issues to help intelligibility, hopefully allowing him to play more quietly? How much bass trapping is usually needed for a room like this?

Here's a couple of my schemes...

Broadband Panel:
Rockboard 60 (705). Do floor to ceiling panels across 3 of the 4 corners (The door is in the 4th). They would be 1.5-2' wide, floor to ceiling (about 7.5ft) and 4" deep. They would be covered with fabric, and supported on the back via 1/8 masonite with wood framing. Could be made to be airtight.

Bass Trap:
Get some more QuietRock (the rest of the room is made of it). Use the same idea staddling the corners, only with the QuietRock installed into the corners, to make airtight triangle spaces. We could stuff some insulation behind them to prevent resonances. The question with this one is at what Hz the sound stops reflecting and starts to pass through...Any thoughts? I suppose it would QuietRock was used. Would this have a limited bandwidth like a Helmholtz? (my understanding is that a helmholtz always has an opening) Would stuffing it with insulation or mineral wool increase it's effective bandwidth?

Deflector/Bass Trap:
Make 1/4 Cylinder "deflectors" somewhat in the spirit shown on Ethan Winer's site. I know this isn't in the true random sense, but it would do something to preserve the high end. We would use thin 1/8th" masonite (bent 90 degrees over 2ft, radius is ~1.27ft) for the face, and make them airtight to the corners. Once again they would be stuffed with insulation (or line the back with rockwool) to prevent resonances. The question on this one is also at what Hz stops reflecting and starts passing into the cavity. Would using pegboard be a better option? Once again, would this operate in a limited bandwidth like a Helmholtz?

Lots of questions...I would greatly appreciate anyone willing to help. Thanks!