anybody acoustically treat their room with QRDs or sound absorbers?

[thadman]

Recently, I visited the local borders to qualm my boredom and picked up a copy of the "Masters Handbook of Acoustics by F. Alton Everest" and have been quite preoccupied with reading this bible of an acoustic book. He discusses the use of Quadratic Residue Diffusors and use of absorbent panels to control reflections/resonances, although he doesn't go into intense detail about the parameters of the concepts and how to accurately and optimally design one. I'd like to apply some of his ideas into my setting and apply some modest acoustic treatments.

I have done some research on the web (miscellaneous webpages and calculators) and made the connection between well width to upper frequency extension and well depth to lower frequency extension, but have not found a correlation between the use of a smaller/larger prime number. Do I need to diffuse >10khz (20khz) or does that diffuse itself? What is a good material and thickness to seperate the wells?

The use of 4" of Corning Owens 703 Rigid Fiberglass also seems more than reasonable (and very effective from the graphs in the Masters Handbook of Acoustics). Should I just place this on the wall? What have you guys done to make it aesthetically pleasing?

[Mazeroth]

I bought a case of 2" OC 703 and put it in 1x3 frames, then covered them in cloth and stapled on the back. It was a quick job for our townhouse basement and I plan on making much nicer ones once we buy our house (got pre-approved yesterday!). I've only made four as of now and had two behind my speakers and two on the side walls taking care of the first reflections. The difference was noticeable but not dramatic. I think to get any real benefit out of it you need to treat a lot of the room and not just place them here and there but take some time to figure out where major reflections are going to occur etc. I also did some before and after measurements which showed only a 1 dB or so change in the frequency response at my listening position. I am definitely going to build another 6-8 more panels for my listening room when we get a house and will do some extensive measurements.

[thadman]

What percentage of my wall panels need to be covered with diffusors or absorbers before a noticeable and appreciable difference in sound quality is achieved?

If it matters at all, the speakers are dipole

[---k---]

look into doing an RT60 calc for your room. that will tell you how much the absorption will do. if you make a spreadsheet, it isn't too hard. I have one somewhere. I followed the example on bobgolds.com website.

I'm not so sure about using lots of absorption with dipoles. doesn't seem right. don't know.

[howburger]

I have 2 X 4 4" Roxul at side wall first reflection points, behind the main speakers and two on the back wall. I am going to remove them and purchase some ready made 2" 2 X 4 panels and build bass traps for the corners. The wife doesn't want 4" panels hanging off of the walls. In my 12' X 20' room, I would not spend any more on audio equipment than I have now, without having treated the room. The result of treating the room is by far the single biggest improvement in sound of anything I have purchased. The following site not only has the panels that I am going to use, but they have a simple calculator that will tell you how many panels you need in your room to get your RT60 to a tolerable level. I'm sure it's far from perfect, but it'l get you a start.

http://www.atsacoustics.com/page--Free-Online-Room-Acoustics-Analysis--ora.html