Last Check BEFORE I Begin DIY Acoustic Treatments

Started by BradJacob on 17 January 2008. 12 replies.

Originally posted at johnlsayers.com, topic 10053.

Guys - Here are a couple pictures of my control room. It is 10'-6" x 11'. It's approx 7'-6" in height. I'm going to build superchunk traps and 2" thick panels. Please take a quick look and let me know if my placements will be enough. Some notes: I plan to install one panel per wall (where wall meets ceiling). The front (speaker) wall will have 2" thick studio-foam in between the traps. I will either (hang or place on stands) two panels that will go against the sliding glass doors while mixing. There will be a cloth couch-like chair that will be in one corner against the bass trap. Will the chair mess up the bass trapping? Am I missing anything? Do I need any additional panels? Many thanks!
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Will the chair mess up the bass trapping?
Nope. The bass wont even notice your chair standing there. It'll go straight through. I admit it, I'm biased 'cause of bad experience with foam-covered studios, but I fear the foam will only mask acoustic problems (instead of solve em). By absorbing the highest range of frequencies flaws in the in-room acoustics will become less easily detectable which might give the impression things 've improved. I'd start out with your planned bass traps. Get a grip on those low thumping sounds. Once your lows are covered, other acoustic troubles will become very apparent. I'd do the rest with movable panels instead of the foam. The bad experience with the foam comes from this radio studio I work in once in a while. They 've covered 3 out of 4 walls + the ceiling in 2" foam. Working in there for more than an hour in a row makes you go bananas...
Sigert wrote:
Will the chair mess up the bass trapping?
Nope. The bass wont even notice your chair standing there. It'll go straight through. I admit it, I'm biased 'cause of bad experience with foam-covered studios, but I fear the foam will only mask acoustic problems (instead of solve em). By absorbing the highest range of frequencies flaws in the in-room acoustics will become less easily detectable which might give the impression things 've improved. I'd start out with your planned bass traps. Get a grip on those low thumping sounds. Once your lows are covered, other acoustic troubles will become very apparent. I'd do the rest with movable panels instead of the foam. The bad experience with the foam comes from this radio studio I work in once in a while. They 've covered 3 out of 4 walls + the ceiling in 2" foam. Working in there for more than an hour in a row makes you go bananas...
Thanks! The foam, is really only for asthetics. It looks cool! Any mid or high freq will be handled (I hope) but the panels. I'll have what's pictured in the photos, as well as one on each wall/ceiling intersection (including the front wall).
The foam, is really only for asthetics. It looks cool!
8)
I'd NOT make your mix position un-symmetric - you have glass on one side, and absorber panels on the other. Not good for stereo imaging. 10.5x11x7.5 will have some modal "bunching" since it's almost square - before you put any but corner broadband traps in the room, I would test for big peaks/nulls caused by nearly equal dimensions - you may need to design some slightly tunable panel resonators to smooth this out, and they MUST be placed in specific locations in order to work. I'm not at my usual computer ATM (temporarily dead) so don't have all the tools to be more specific - check out links for the Harmon mode calculator and Jeff's modesV2.xls, should still be available for download at studiotips. These will tell you where your modal problems should be, but measuring is even better... Steve
knightfly wrote:
I'd NOT make your mix position un-symmetric - you have glass on one side, and absorber panels on the other. Not good for stereo imaging. 10.5x11x7.5 will have some modal "bunching" since it's almost square - before you put any but corner broadband traps in the room, I would test for big peaks/nulls caused by nearly equal dimensions - you may need to design some slightly tunable panel resonators to smooth this out, and they MUST be placed in specific locations in order to work. I'm not at my usual computer ATM (temporarily dead) so don't have all the tools to be more specific - check out links for the Harmon mode calculator and Jeff's modesV2.xls, should still be available for download at studiotips. These will tell you where your modal problems should be, but measuring is even better... Steve
Hey Steve - haven't heard from you in a while. Nice to have you (back?) Yeah on the side with the glass, I'll have the same acoustic panels as on the other side. These will be on stands so I can remove them when tracking. I don't know quite "how" to test my room? How does one do that? And the bass traps will be those superchunk with a 24" face. Does this help or change anything? Thanks.
Superchunks in corners are a good first step, doubt if there's a room that wouldn't need 'em. Testing - go here http://www.etfacoustic.com/ and, after you've read thru all their site and gathered a lot of info, if you can't afford their product go here http://www.hometheatershack.com/roomeq/ Also, David French has been using the above software for some time and has lots of insight - you can find him at recording.org, studiotips, and occasionally here... Steve
..., and they MUST be placed in specific locations in order to work.
Is that so? I wasn't aware of that.
"and they MUST be placed in specific locations in order to work" Reason for this is that panel traps are a resonant membrane - they work where the sound PRESSURE is greatest, not the sound VELOCITY - so in order for a panel trap to work optimally, it needs to be where peak pressure is generated. For simple axial modes, this could be at either end of the dimension that's causing the mode, or (if it's a 2nd/3rd/4th harmonic, at any point along the ADJACENT wall(or ceiling) where that specific mode has pressure peaks. For a second harmonic, there will be pressure peaks at both ends and the middle of the wall/ceiling that is ADJACENT to the two walls responsible for the mode - for a third harmonic, both ends and at 1/3, 2/3 of the same adjacent wall. Also, because a panel trap causes extra leaves in a wall when placed anywhere near it, they will lower the TL of that wall - especially at the resonant frequency, within an octave or three depending on inner construction (how much insulation's inside, mostly) HTH... steve
I've only just reached chapter 8 of the 'master handbook of acoustics' so I don't rly grasp what you just said. But it makes me look forward to the part about modes... :)
... it was every bit as fascinating as I'd hoped it would be. :lol:
Sigert wrote:
... it was every bit as fascinating as I'd hoped it would be. :lol:
Many thanks Sigert! :wink:
Sigert wrote:
... it was every bit as fascinating as I'd hoped it would be. :lol:
Many thanks Sigert! :wink: