You can't have too many bass traps...


Hej

I've read that you can't have too many bass traps. Is that really true? 
simna

Showing 2 responses by replaceablehead

I know I'm grave digging here, but the information is so egregiously incorrect, I had to say something.

I'm going to assume we're not talking about tuned traps, but rather absorbers.

You cannot have too much bass trapping, for the simple reason that at a certain point, with enough traps, all reflections will be totally absorbed.

There's one major problem with most of these replies, they seem to assume the OP has a decent sized room, but chances are the room is small.

There are two approaches to eqing a room, tuning it by targeting problem frequencies, or damping until the whole thing is flat.

If you have a small room, approach 1 probably isn't going to work. Chances are the acoustics are so bad, you just need to remove them all. The only "liveliness" a small room has is the janky kind.

Thinking about most untuned traps, they are actually cutting the high end at a more efficient rate. So if you only put a few in, you'll end up effecting the high end first. As you add thicker and thicker trapping the low end starts to catch up, until finally you get to the point were everything is absorbed.

So the problem most people on this thread are probably having is using no where near enough bass trapping. Question: is it feasible to use that much? It doesn't take thaaaaat much. I mean you'll have to sacrifice real space, but trying to hang Owens corning here there and everywhere isn't terribly space efficient either.

Cheapest way, take a small room, measure off 1 meter, make a false wall with cheap timber and fill the entire cavity with cheap fluffy fiberglass insulation between 4000 and 6000 rayls/m (most is, but check the GFR first). You'll loose a meter of space, but you can use much cheaper insulation and it will be better down to waaay lower frequencies. Now test the room, if it's not pretty flat, add more and make them thick.

Option two is to strategically try and tune the room, good luck with that.
Find the GFR in rayls/m3, or pa.s/m2 and match the thickness to the GFR. Use a calculator http://www.acousticmodelling.com/porous.php

"Get the rayls, use the calc, get the rayls, make them thick". Don’t guess, don’t use density kg/m3. Get the right figures. Thick is good.


Getting a suitable mic, small condenser, or proper measuring mic and using Room Eq Wizard is a good idea. But I would still say accurate GFR is the single most important thing to know. Room Eq Wizard graphs are hard to interpret and can make you feel hopeless. I’ve seen plenty of guys use Room Eq Wizard and then proceed to do a very poor job of treatment followed by another REW test that they interpret positively because they’re inexperienced and desperately want to see an improvement. If you get the rayls, use the calc, make ’em thick, and use plenty you should get good results.

And one last time, you cannot have too many, the only issue you’ll run into is having just enough to screw up the high end and not enough to tame the low end. Again, assuming you’re not trying to surgically target frequencies in an already pretty good room ie. an actual recording studio. If it’s a small room in your house, you need to take a deep breath, accept that you have limited options and make ’em thick son.