Quote:
Originally Posted by JouCalle  OK, but are you SURE? Doesn't a porous absorber work by braking the air-molecules that go through? With plastic in front, do anything really go through or does it work like a membrane?
Could anyone explain the physics? Thanks! |
I believe Ethan Winer explained this not too long ago within another thread. I'll look around for it and link it here if I can find it.
I was concerned about the same issue, wasn't sure if the entire thickness of the trap would need to be "free-flowing" with respect to AIR movement in order to be effective, but I was assured this is not the case. OF course if you have a sheet of plastic as your final finished layer, you are going to get a lot of upper frequency reflection off that, but if you have some degree of absorption in front of the plastic, then the plastic should not have any adverse effect on the trap... at least how I understand it based on what the knowledgeable people of this forum have explained.
In my opinion, you do not really need to worry about building reflection into your bass traps, if you need a little extra reflection, just leave a certain degree of the already reflective surfaces in the room uncovered. Or add some separate diffusors, etc.
As I may have mentioned in another post somewhere, since my room is so small, I AM pretty much covering almost all surfaces with bass traps because I do not want ANY close reflections happening. Will the room sound too dead? Maybe. But too dead is better than nasty ugly close reflections with resulting phase gremlins and other weirdness.
BUT, if I do find it way too dead to the point of ridiculousness, I may just try nailing some thin wood strips on the front of the traps, at different angles, etc... this will add a bit of reflectivity and a theoretical tiny bit of diffusion (if I have a bunch of different angles happening). What I like about this idea, you can add wood strips little by little until you gain just the right amount of reflectivity. And adding scattered strips also will yield a scattered reflectivity which is likely better than having one huge flat reflective surface in one spot... with a scattered "grid" of reflectors, I'd think the chance of having a nasty close refection issue in a given spot would be way less than otherwise.