where to place foam ?

[alecmcmahon]

hey guys... i just bought about 160 sq. feet of eggcrate foam for my vocal booth.

and 48 sq feet ( 12x12x1 ) Wedge Foam to start treating the control room ( and maye some live room ? )

anyway... this is roughly the basement plan, i did it in about 2 seconds, i'll try to get real measurements soon






anyway what would be the best postioning for the control room for THIS foam ???

thanks


edit - here is the picture..

 

[fitZ2]

It never ceases to amaze me how design FOOLS people. Snake oil strikes again.

alecmcmahon, Let me enlighten you. Although these products have a FANCY name WEDGIES, and the fancy anachoic room look to them, and do SOMEWHAT perform, here is the REALITY. Foam is a RESISTANCE absorber. A resistance absorber only works because the movement of air molecules is reduced by FRICTION. AND, the frequency at which absorbancy occurs is governed by the THICKNESS of the material. This means, the thicker the material, the lower the frequency BAND of absorption. If you have a 4" thick panel of FLAT foam, it will absorb to its lowest frequency BETTER than a panel that has been machined to look fancy, BECAUSE MATERIAL HAS BEEN REMOVED!! These WEDGIES absorb at high frequencies because of the thin design. They have very limited performance at MID and almost ZERO at low frequency. So what they end up doing is SUCKING all you high end energy out of the room if complete walls are covered. To some extent, they will break up reflections, if used in patches, as that creates diffusion, in a limited fashion. Your money would have been better spent on RIGID FIBERGLASS panels, as their absoption COEFFICIENT is much HIGHER. But, some people think looks are more important than performance. I don't get it though.

fitZ

PS. Total absorption is goverened by the PERCENTAGE of area covered. The absorption COEFFICIENT determines the amount of absorption per square foot, and is usually stated in SABINES. A one square foot window, has ONE SABINE of absorption. BTW, a window is a perfect absorber.

 

[alecmcmahon]

fitz, thanks for the reply....


i understand what you mean with the thickness and such... but as to quote myself ... " and 48 sq feet ( 12x12x1 ) Wedge Foam to start treating the control room "

i figure it wouldnt hurt spending 20 some odd dollars on some foam , it cant hurt right ? in the future i do plan to add more absorbtion... but in the mean time there are other things that have to get done.

 

[Innovations]

fitz, thanks for the reply....


i understand what you mean with the thickness and such... but as to quote myself ... " and 48 sq feet ( 12x12x1 ) Wedge Foam to start treating the control room "

i figure it wouldnt hurt spending 20 some odd dollars on some foam , it cant hurt right ? in the future i do plan to add more absorbtion... but in the mean time there are other things that have to get done.

Ok but here is the problem. Let's say that the place that most needs absorbtion is the wall behind the speakers in your control room. You put your foam wedgies there 'to start'. Now time comes along and you buy or build some fabric coated two inch semi-rigid fiberglass panels that are better than the foam. Where do you put them? On the back wall? Oops! The foam is already there. So you either rip down the foam, quite likely damaging it in the process, Or you put your fiberglass in the second-best place. Or you plan for the fiberglass all along and put the foam in the second best place.

 

[alecmcmahon]

ok.... again, i understand... but FOR NOW, where would the best place to put them be?????????????

 

[fitZ2]

Hello alecmcmahon, say, didn't mean to give you a hard time. Sometimes I come off that way. Ok, what you have is the equivilent of a sheet and a half of 4x8 ply. Personally, I would use 4 pieces, diagonally ACROSS the wall intersections(corners) at each end of your console, 12" from the ceiling on down or from the console height uppward. To do this, nail a 1x1 wood cleat vertically on each wall, so that it measures 1/4" smaller between the cleats diagonally across the corner, than the tile face dimension. Just force the tiles in between these cleats or glue them along the vertical edge. Thats 8 pieces total. That leaves 40 squares. I'd use 8, in each of the rear corners, floor to ceiling. That leaves 24. Then I'd sit at the engineering position, and have someone hold a mirror about the same size as the foam tiles, and hold it against ONE side wall, and move it around till you see a monitor in the mirror from the engineering position. Think of that as the CENTER of a soundwave EARLY REFLECTION, and the intersection of 4 tiles forming a square. Then do the same on the opposite side wall. Now, I would use another 4 tiles in a square, or 6 tiles in a rectangle, on the ceiling right above but a little forward of the engineering position. Use the mirror if you can. Then use the balance of the tiles on the rear wall behind the engineering position, in a checkerboard pattern, two rows high, centered on the wall, the horizontal line between two tiles at ear height. This will provide some diffusion at the rear wall, as well as more absorption than the tiles placed side by side, as there is a phenomena called the "edge effect", which states more or less, that ........."the total absorption of a given square footage of absorbant material is increased if this square footage is divided into patches, where each patch has a reflective boundary along each of its edges"....?Don't ask me why. All I know is that it exists, as tests have confirmed it ALSO, the edges of absorbant material contribute to overall absorption, and anyone who places 2" to 4" fiberglass panels in wood frames looses a LOT of absorption, as the perimeter length of a 2'x4' panel times the thickness equals a LOT of area that contributes to the overall absorption. Hmmmmmmm, does that make sense? On ONE 2" thick panel, thats a whopping 288 square inchs, or 2 full square feet of absorption area!!! On ONE panel So, you can see that multiple panels can loose a lot of area by covering the edges. Not only that, but the absorption is at 90 degrees to the face, so incident angle absorption increases too, if there is a reflective boundary next to it or not.
BTW, you will also lower the bandwidth of your tiles, if you glue a piece of 1" square foam or wood "standoff"at least a half inch thick on each corner of each of the tiles used parallel to the wall and ceiling. This gives an airgap behind them, which technically is just increasing the "thickness" of the tiles, but also, reducing the "waste" of the tile thickness as velocity of molecule movement at a boundary(the wall behind the tiles) is ZERO. Well, hope this helps, and again, this stuff is mostly covered by my disclaimer, and subject to abuse by the user or other replys by experts.
fitZ

PS, since your console is so close to the wall and speakers, you MAY not see the monitors in a mirror. In that case, use these tiles right up next to the front corner tiles, vertically. Well, thats my .02 anyway.