I made some with balsa wood 2x2 planks. Email me directly for more info. I can send you a spreadsheet with my design.
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You may want to take a look at the wood conical sound diffusers that cover the back wall in the renovated auditorium at Alice Tully Hall in Lincoln Center. There is an article in the New York Times that appeared last Thursday. Go to nytimes.com/music. It is the first time I have seen such construction. Hard to estimate the height of the conical pieces. Not clear why a conical construction would work. Would not be hard to duplicate. Anybody have any idea what these will do? |
Per several requests, my procedure for making wooden diffusors, similar to RPG Skylines, was as follows: 1) Purchase 2"x2" balsa wood planks from nationalbalsa.com in 3' lengths. Make sure to tell them that the planks need to be truly square in cross-section and truly 2x2 in dimension. 2) Purchase 1/4" plywood backerboard, cut it into manageable size sheets (e.g. 2'x2' or 2'x4' - too big will yield too heavy diffusors when you are ready to mount them).Get a hot glue gun (or 2) and some special hot glue sticks for wood. 3) Stain the balsa planks on their long sides. 4) See design formula at: http://www.mhsoft.nl/DiffusorCalculator.html NOTE: I just noticed that the link doesn't seem to be working, but I've got it captures on a spreadsheet for my particular design and there may be others out there that calculate the well depths and dimensions for an RPG diffusor. The formula specifies 5 sizes for blocks to be used to construct the diffusor. One of the sizes is zero (no block at all, just the plywood showing). 5) Get a chop saw and go into production. You will need to cut hundreds of blocks - 4 sizes total. It'll take a couple of hours, best with 2 people. Just set up a jig for the length that you want, and away you go. 6) Stain one face of each block - this will be the outside face. This will take a couple people a few hours (good to get a kid involved in this). You can also stain the outside face of your plywood backer board, or do it later once the blocks are attached. 7) Once all the stain is dry, get out your hot glue gun and start assembling the panels. This takes lots of time. I glued the blocks to the backer board, and sometimes to each other. Follow the recipe for the layout obtainable on the web (or my spreadsheet). 8) Mount them on the walls. You can place bolts with washers in the "zero wells" - that is, the wells with no blocks. They look like are peices and they sound great! Good luck. |
Peter S. thanks - great post! If you can afford 90 tons of timber here is an example of just how far one could go. In the pursuit of great sound there is no such thing as madness but surely this comes close! Spaz, If you look at my virtual system you can see an interesting fireplace. What do you see?...yeah I know its just a fancy fireplace...that is all anyone ever says....look closer now and put your audiophile hat on and you might suddenly realize you are actually looking at a highly effective RPG diffusor as well as bass trap behind the listening position. Go on be creative - acoustic treatments do not have to look like something out of Star Trek to be effective. |
Buconero, Thanks for the link to see these panels. I made something similar in ways except the inverse. I built angular enclosures around my ceiling mounted video screen and a soffit overhead surrounding the ductwork. The enclousers are built of birch plywood and mounted to the studs. In between the studs, pre existing drywall and enclosures are brass Audiopoints and Apcd coupling discs. The panels are then tensioned and secured to the studs with brass wood screws,painted and finished out. Instead of the 90 degree angles that were there or would have been built around the screen box I used angles of 38 and 52 degrees. Some of these angles face towards me or away from me. My idea was to mitigate cancelation caused by 90degree angles. Use all the energy present in the room and to refocus and reuse the energy. Excess would be redirected by the orentation of the points and coupled and dissapated thru the room supports. My result was both musical and focused without excess brightness. From the photo in the Times it appears to me that there is a wood veneer applied over what maybe a softer surface{for a slight amount of absorption] to make the panels. The sharks teeth described look like a slight variation of a point used for audio coupling. Wonder where they got that idea for a shape from? The conical shape may collect, capture and diffuse different frequencys at varying angles of departure. All the energy generated would be present only reused and refocused. I wonder what material the conical points that make up their panels are made of? Wood, brass, or bronze or a combination of patterns made of such materials? The Musikverein in Vienna is made up of mostly hard irregular surfaces contradictory to many designs and materials used today. Perhaps Alice Tully hall is revisiting and reusing some of these "outdated" ideas and materials. Tom |
How about Charles Altmann approach See the photo here used by Mike Pranka of Dynavector Systems, New Zealand. Mariusz |
