Covering broadband traps question

[Carnivale]

Hi there,

I’m putting together some broadband traps (Roxul based) and I think I made a mistake. I wrapped one of my traps in burlap and now I’d like to put some felt on top of it. Will it make my traps less absorbing? Normally, I just put one layer of felt but this particular trap is going to be hanging right above me (above console) so I just wanted to make sure that the particles from Roxul wont fall down. Anyway, would it make the trap less affective if it is covered by burlap and felt at the same time?

Thanks

[Bob Olhsson]

My personal preference is some kind of perforated board facing so the highs won't be eaten up more than the lows.

[Ethan Winer]

Originally Posted by Carnivale

now I’d like to put some felt on top of it. Will it make my traps less absorbing?

No, felt is fine. You don't need "acoustically transparent" material to cover an absorber. If the material absorbs a little more on its own no harm is done. It's not like speaker grill cloth in front of a tweeter. However, Bob is also correct that too much absorption at mid and high frequencies can suck all the life out of a room. This is one reason "high end" professionally made bass traps are built with a membrane of some sort. They absorb as much bass as possible, and absorb less at higher frequencies. But for a cloud overhead, having it fully absorbent at all frequencies is appropriate. So go ahead and use the felt.

--Ethan