Absorption values for ceiling tiles

tomlinmgt

Lunatic Member
Anyone have these figures? Trying to see how the acoustic ceiling tiles compare to the compressed fiberglass panels as I have access to a bunch of them from an office space tear out and my listening space is in desperate need of bass traps and side/rear wall and ceiling absorption panels. Was wondering what frequencies would be absorbed if it was a single, double, or triple stack with air space beteen the double and triple stacks. Or perhaps a sandwich with fiberglass in between the tiles. Ideas/experiences???
 
It turns out there are quite a few different types of ceiling tiles. If you got them from an office that's not a high-dollar building, chances are they're in the NRC 0.55 or NRC 0.65 range. Here are a few generic values for ceiling tiles like that:

NRC 0.55 Ceiling Tile:
63: 0.16
125: 0.32
250: 0.31
500: 0.52
1000: 0.68
2000: 0.73
4000: 0.68
8000: 0.68

NRC 0.65 Ceiling Tile:
63: 0.19
125: 0.38
250: 0.36
500: 0.54
1000: 0.79
2000: 0.84
4000: 0.88
8000: 0.88

I'll add those values to the absorption value spreadsheet.

You absolutely can stack ceiling tiles for better low frequency absorption, and I have seen this done. Just make sure they don't have any kind of rigid or membrane backing. Some ceiling tiles look the same on the back as they do on the front, so sound will pass through them and into another tile behind. These you can stack. Some tiles, however, have a dense rigid material on the back for strength, or some kind of membrane on the back. If that's the case, sound won't pass through the backing easily, so you won't get much benefit from stacking.

I don't know what kind of low frequency absorption you would get by stacking. I think it would need to be tested, because I don't know if there's a way to numerically work it out. Just as a wild ass guess, I would say you'd gain about 0.1 in each band below 1k for 2 tiles and 0.15 for 3 tiles.

You could also sandwich fiberglass between ceiling tiles for structural reasons, though I don't know if there'd be much acoustical advantage to doing this vs just stacking tiles. The fiberglass is a better absorber, so it should be exposed to the sound directly, if possible. Unless you're more interested in absorbing low and mid frequencies, then I guess it would be sort of like putting fiberglass behind peg board.
 
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