[GregN]

room looks mighty fine, nrenter.

Maybe I missed this part, but what is the point of the quarter round bass trap underneath the desk? Is this a commonly applied location for treatment? Or perhaps the better question would be.. under what circumstances would this location be suggested for bass and/or full absorption/trapping?

Am I correct in suspecting that the primary rationale for this particular placement is that it's the best location in the room for reducing the treatments visibility, and not as much with it being an ideal acoustic location for that third quarter round treatment? In other words, it will still be beneficial there, but from a pure acoustical treatment standpoint, there might be other locations within your room where it might be even more beneficial.

[nrenter]

Frankly, I think you said it best:

...it's the best location in the room for reducing the treatments visibility, and not as much with it being an ideal acoustic location for that third quarter round treatment? In other words, it will still be beneficial there, but from a pure acoustical treatment standpoint, there might be other locations within your room where it might be even more beneficial.

I wanted more bass traps in my room, could not reasonably find symmetrical locations for an additional two traps, so compromised by placing one under the desk against the wall. In a cubical room, I figure I can use all the help I can get.

[GregN]

Agreed.  I was trying to stay within the panels he already had.

If I was to start from scratch, I'd use solid triangular chunk style absorbers in the corners instead of the quarter rounds.....

about that.. are you saying this because the particular corner absorber he is using is somewhat hollow? What is the design philosophy here in not making it solid? They could have easily designed it this way. Or, is its comparatively narrow (left to right) width more of the issue than the depth of it's material composition? Would a taller version of the same help compensate for whatever deficiency in depth or width that I assume you are attributing to it?

In other words, why do these damn corner treatments always have to be super wide and super thick to be most effective, sticking all the way out to Kalamazoo?!? 

[nrenter]

In other words, why do these damn corner treatments always have to be super wide and super thick to be most effective, sticking all the way out to Kalamazoo?!?

I think that's just physics. However, as you can see from my photos, the traps I chose are relatively benign and quite effective. Bigger is probably better, but like all things in engineering and marriage, it's about trade-offs. I'm giving up some effectiveness for (IMHO) aesthetics.

[GregN]

I wanted more bass traps in my room, could not reasonably find symmetrical locations for an additional two traps, so compromised by placing one under the desk against the wall. In a cubical room, I figure I can use all the help I can get.

I think that's just physics. However, as you can see from my photos, the traps I chose are relatively benign and quite effective. Bigger is probably better, but like all things in engineering and marriage, it's about trade-offs. I'm giving up some effectiveness for (IMHO) aesthetics.

gotcha.

I'm right there with you on this sort of thing (or, maybe I should say with your wife more so than you ). I want a good sounding room, but if it's not going to be 100% dedicated to audio, I would prefer to sacrifice a bit of ideal acoustic quality in favor of making the room more aesthetically pleasing. Finding the ideal compromise is the challenge. obviously.

Now, I'm just hoping someone will get a little more specific about quantifying how much and what specific range of absorption is being sacrificed with these smaller/narrower types of bass treatments vs. the ideal (really large) kind. I'm not so good at interpreting the absorption coefficient data I see. 

Is it as simple as, for example, a half as wide or thick treatment will have it's lower frequency absorption effectiveness cut by half? Or, is there some other simple multiplier one can apply to get a good idea of just how much and what frequency range will be sacrificed?

Incidentally nrenter, how wide are your quarter round broadband treatments? Is that the 16" "diameter" measurement as described on the company website? What is the front to back depth? 

[nrenter]

I'm going to defer to those on this site with far more knowledge of acoustical treatments than I to answer your technical questions about the effectiveness of various designs. When comparing the absorption coefficient data of these traps to others, I felt these were relatively "good enough" particularly given their unobtrusiveness.

However, I can answer your other question - the quarter-round traps I use are 16" diameter (assuming they were round). So when these quarter-round traps are placed on the wall, they stick out 8" on each wall.

I also recommend taking some time with a roll of painter's tape and experimenting with sizes and placement for aesthetics. A 4' trap really isn't that large. My traps (and side panels) are 12" off the floor (but the panel behind my desk is 18" off the ground).

[GregN]

Sorry nrenter, I feared that you might think that I expected you to answer my more technical questions. Wasn't my intention! Those questions were thrown in more or less for the experts who congregate on this forum, should one wander on by.

With regard to yours, 8" isn't bad at all. I could probably even go 10" to 12" deep on something like that, in a rounded type of quarter corner treatment. I don't have a problem with it being 4' tall either. I could even go taller there if it would help mitigate the loss of depth/width. The only thing I really have problems with are the 2' wide, 14" to 18" deep treatment monsters. Not willing or able to work with something like that.

[nrenter]

I completely understand. I'll quote myself from the opening post of this thread:

And before someone types "big-ass bass traps", there will be some WAF involved in all decisions regarding room treatments.

Just be wary of "custom sizes". They will kill your budget.

[GregN]

.. and my will to live. I'll steer clear, thanks.