Yes, Fire rated materials only. If you have any doubts please send me a copy of the material’s ratings and I will personally show it to the Fire Marshal. We, that is DMS, have been down this road before with the Fire Marshal.
Owens Corning 703 wrapped in the fabric of your choice. Variations of that depending on the offending frequencies. This is the go-to when we’re treating auditoriums/studios/theaters, etc.
The foam stuff works, but it’s noise coefficient ratio isn’t as consistent across freq ranges. Also, not as potentially attractive depending on your choice of fabric.
That’s exactly the idea. We usually use a combination of multiple sizes and use vampire clips to make the mounting incredibly easy.
@kbraby, that’s one way, but if I remember right, the foam only adds absorption in the upper ranges, which are already pretty well handled by even 1” 703.
If you’re trying to handle speech echo, 1” will do great for you. If the echo sounds more hollow, go with 2” as this likely indicates a lower freq culprit and will also cover the upper ranges. 4” is typically only used if you’re dealing with strong bass sources (bass guitars, kick drums, etc).
You’ll probably get a pretty good result from a few panels placed on perpendicular walls. The opposing wall will still reflect, but it won’t have anything to reflect back to it and continue the delay (echo).
Just make sure that the covering you use is also Fireproof. A spray on fire retardant will not work. If the covering material has a Fireproof rating, them keep the datasheet as proof for the Fire Marshall. If you have questions, send me a copy of the covering material datasheet and I’ll personally contact the Fire Marshall for approvals before you spend your money.