I couldn't find any threads were people tried to measure bass trap effectiveness (no bass trap then add bass trap etc) so I did a simple experiment.
I measured the reponse with an untreated room, then added one floor to ceiling superduper chunk column in the right rear, then added another superduper chunk column in the left rear and finally added a regular super chunk nine feet long along the front floor/wall boundary. After each addition I remeasured. The superduper chunks were humongous at 34"x24"x24" and the regular super chunk was the normal 24"x17"x17". So I didn't skimp on the material!
Here's what I found:
Baseline:
Right rear column added:
Left rear column added:
Front floor chunk added:
I note the following:
1) Below 40hz there doesn't seem to be much effect.
2) Surprisingly the 40-50Hz region improved with each superduper chunk. Presumably reaching this low is due to using the bigger chunk size.
I was planning to cut these in half to regular size but now wonder which is better...larger chunks but only two columns, or regular size chunks which gives two extra column worth of material to use elsewhere. Any advice?
3) Adding the second rear column changed things as did adding the front floor column but did it get better? I'm not sure. Certainly there isn't a steady march to filling in the peaks/valleys...each one clearly better than the last...! In fact the first column seemed to smooth things the most. What is happening? Pehaps reflections from walls are starting to dominate that aren't being addressed by the corner chunks. Once again, comments from the cognoscenti appreciated!
4) Changes in the 80hz peak is interesting. It improved the most with only the right rear corner. Then regressed although in all cases it is better than untreated.
5) Some pretty deep nulls seemed to be introduced! Complete cancellation at some points where previously there was some energy.
Overall, to be honest, I don't see the improvements I had hoped. Especially given the huge size of these things in the corners. Since this was a test, I'm not going to necessarily keep it this way. But, based on these plots, it isn't so obvious what would be the best deployment of all this stuff either...
I measured the reponse with an untreated room, then added one floor to ceiling superduper chunk column in the right rear, then added another superduper chunk column in the left rear and finally added a regular super chunk nine feet long along the front floor/wall boundary. After each addition I remeasured. The superduper chunks were humongous at 34"x24"x24" and the regular super chunk was the normal 24"x17"x17". So I didn't skimp on the material!
Here's what I found:
Baseline:
Right rear column added:
Left rear column added:
Front floor chunk added:
I note the following:
1) Below 40hz there doesn't seem to be much effect.
2) Surprisingly the 40-50Hz region improved with each superduper chunk. Presumably reaching this low is due to using the bigger chunk size.
I was planning to cut these in half to regular size but now wonder which is better...larger chunks but only two columns, or regular size chunks which gives two extra column worth of material to use elsewhere. Any advice?
3) Adding the second rear column changed things as did adding the front floor column but did it get better? I'm not sure. Certainly there isn't a steady march to filling in the peaks/valleys...each one clearly better than the last...! In fact the first column seemed to smooth things the most. What is happening? Pehaps reflections from walls are starting to dominate that aren't being addressed by the corner chunks. Once again, comments from the cognoscenti appreciated!
4) Changes in the 80hz peak is interesting. It improved the most with only the right rear corner. Then regressed although in all cases it is better than untreated.
5) Some pretty deep nulls seemed to be introduced! Complete cancellation at some points where previously there was some energy.
Overall, to be honest, I don't see the improvements I had hoped. Especially given the huge size of these things in the corners. Since this was a test, I'm not going to necessarily keep it this way. But, based on these plots, it isn't so obvious what would be the best deployment of all this stuff either...