Audio foam placement
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Posted on Jul 12, 2014 10:22 am
dbmasters
Administrator Since: Apr 03, 2002
Just curious here, what are people's different theories (or proven facts) regarding the placement of pieces of audio absorbing foam?
I have about 16 2x2 sheets right now, started hanging a few in obvious places, like using them to interrupt long, flat surfaces or places like that...and it got me to wondering what other folks do when they hang it, how they decide where, or, do people use it as more of a "it looks nice there" sort of thing?
Thoughts?
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J-botByte-MixerMember
Since: Dec 04, 2007
Jul 13, 2014 02:18 am Well, depending on the density, thickness and material of the foam, it's probably okay for absorbing high frequencies, maybe even upper mids if it's dense enough, and there's enough of it.
But, well, low/bass frequencies and lower mids are going to go through foam like water through a sieve. If you're just trying to make the room a bit less lively, and kill some flutter echoes, then they're fine for that. But they're not going to do much for the bass.
As a rule of thumb, you use foam panels as kind of like the finishing touches on a room after you've got your bass traps and broadband panels up. They shouldn't be your end-all-be-all treatment. For foam, there's probably a when, where, and why for using it. I would space them evenly along bare stretches of wall, but stagger the position a bit, either staggered on the same wall, or on opposite walls.
Here are a few charts for acoustic absorption coefficients. Very basically, the closer you get to 1.00 as the coefficient at X frequency,(or even over 1.00) the better the material is at absorbing those frequencies.
Some common materials:
www.sae.edu/reference_mat...ent%20Chart.htm
This is a good site, but I don't think it covers foam.
www.bobgolds.com/AbsorptionCoefficients.htm
And of course the obligatory RealTraps/Ethan Winer explanations:
realtraps.com/art_measure.htm
But yeah, how well the foam absorbs depends on its density, how much you're using (thickness) and the type of material.
I've been digging into this and talking to some people who have a more solid grounding in acoustic design than I do. I want to properly (as close as I can) treat the new room when we move. Particularly since the walls are made of plaster rather than gypsum/drywall/sheetrock stuff.
Hope that gives you an idea. Oh, and one last thought (as I was told at least): high-frequency symmetry in the room is important, so that will factor into placing the foam.
Jul 13, 2014 12:44 pm I am kinda lucky insofar as I only have a couple or real corners to worry about considering the volume we'll usually play at compared to the r0om itself, so hopefully bass trapping and lively corners won't be a huge issue.
After placing the foam I have, I figure I'll jam a couple times and see how it goes. My bigger issue is the little nook the recording PC is in, that might be a bigger issue than anything.
Thanks for the input!
BeerHunterwww.TheLondonProject.caMember
Since: Feb 07, 2005
Jul 14, 2014 10:24 am I think this depends on what you are starting out with. We have an audio booth that is covered in foam. Every wall, the ceiling and even the floor. We use it for testing and although I haven't done any formal measurements, the room is dead as dead can be.... feels like sound is being sucked out of your ears. Now then I cannot see past the foam so it could very well have some broadband material behind the foam. The room is soundproof. I will take some photos
zekthedeadcowEat Spam before it eats YOU!!!Member
Since: May 11, 2002
Jul 16, 2014 12:53 pm As far as placement goes I sit in my chair and observe the room from the perspective of what the sound would have to bouce off of the get back to me. So basically a panel would be on the side wall, headlevel about halfway between me and the speakers. Front wall 2 panels evenly spaced between my head and speakers... and as much of the back wall as possible. Two even with the side wall panels on the cieling and floor rug.
Jul 17, 2014 01:19 am you can get a free room analysis from Auralex. It took a couple weeks but it is pretty detailed. I have not done anything with the room yet.....www.auralex.com/
WaltChief Cook and Bottle WasherMember
Since: May 10, 2002
Sep 02, 2014 12:09 am I've got foam along one side of the studio. I came across a bunch of cubie panels 1/4 in rigid fiberglass which is cloth covered. I use those with art, African masks ect on the front of them intermittently though out. Hung two 4x4 panels as clouds. Per pink testing pretty flat. Plenty of stuff, chairs, keyboards, shelves, so things are pretty broken up. Have a door to the kitchen and a built in cupboard at the rear of the studio where I leave the doors open to create leaky wall bass traps. Flat down to about 35hz. Per testing with geq, that super low end is of little significance in the room. Use a dab of eq on the mains of the board to get flat from about 35 to 18k. Works out pretty good. Do a lot of entertaining as the room is still pleasant and great for simply listening.
