I started looking into acoustical treatment several months ago. I decided I did not want to spend a lot of money on treatment and I would make it myself. I read every web site I could find on the subject. Originally I thought I would use Owens Corning 703 and 705 attached to a frame covered with burlap on the front only. I was going to use pieces of 2” x 2” screw to the back of the frame to hold the rigid fiberglass in place. I decided on doing bass traps and reflection point treatment. However for this post I mainly wanted to concentrate on the panels I made for the reflection points since they comprised the majority of what I made. I was thinking about diffusers in the back of my home theater but the more I read I decided that diffusion would not be as effective as absorption in my room due to its size and the proximity of the walls to the seating area. I have a relatively small HT room 13’ x 17’ x 8’.
I decided to let my fingers do the walking and called several local insulation companies to avoid shipping charges. Shipping on the insulation is very expensive. I found Owens Corning and Knauf locally cheaper than I could buy it on the net mainly due to savings on shipping costs. Then I one of the companies I called told me that they could get whatever I wanted (Owens Corning, Knauf, etc.) but that they had some IIG Sound Attenuating Fire Batt in stock that was left over from a previous job and they would sell it do me at a discounted price. So I picked up about 40 panels of 2’ x 4’ x 2” IIG MinWool Sound Attenuation Fire Batt Insulation at approximately $0.20 a SF that’s about $1.60 a panel. Calling locally really save me some big bucks on the insulation. I paid $1.60 for a panel of IIG MinWool as opposed to $15.00 for a panel OC 703. The sound attenuating propertied of these two items are practically identical and can be found on their web sites.
The first problem I encountered is the MinWool was very flexible and friable. I would think the more rigid stuff would be easier to work with. This material would definitely require a frame with a back. So I decided to use burlap for the back instead of the 2 x 2s. The 2 x 2s would never have worked with the MinWool because it is very flexible and friable. However I was not too crazy about the texture and color of the burlap so I decided to use acoustically transparent fabric from Acoustimac
http://www.acoustimac.com/index.php?option=com_frontpage&Itemid=9 for the front of the panels. The fabric is about $9.00 a yard however it is 60-64” wide. This material has a great texture is stretchable and comes in a nice variety of colors. I spend a little extra on the fabric because a yard of 60” burlap can be bought for about $2.00. Then on the other hand a yard of Guilford of Maine fabric costs at least $15.00 a yard.
For the frame I use 1” x 4” x 8’ pine stripping. This is the lowest grade of pine that can be found it was $1.65 for an 8’ board. I had to inspect every board carefully before I bought it because most of them are bowed, warped, or damaged. However after weeding through the boards I was able to find enough good boards to make all of the frames for my panels. I had much better luck finding good boards at Home Depot as opposed to Lowes.
It cost me about $15.00 to make a 2’ x4’ acoustical treatment panel. I treated about 30% of my room’s surface area not counting the floor. This includes bass traps that were placed in the corners. I made approximately 30 panels. I could have made them a lot cheaper if I would have used burlap to cover both the front and back of the panels. In that case they would have been approximately $7.50 a panel. However the panels I made turned out real nice. The main reason they were so cheap is because I was flexible on the type of insulation, wood, and fabric I used and called around to get the best price. Most of this type of insulation (rigid fiberglass, mineral wool and rock wool) has very similar acoustical properties. The acoustical properties for the individual products can usually be found on the manufactures web site.
