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Thread: Fixed My Loud Amp Ceiling Rattle!

  1. #1

    Fixed My Loud Amp Ceiling Rattle!

    My DG30 rattles a room more than my HXDA even though the wattage is lower. It's loud, but of course, it sounds best that way. The HXDA doesn't really rattle my room at recording volumes, unless I go overboard with volume. The DG30 shakes it at my usual recording volumes. Just the way it is.

    The problem, of course, is that my studio's recording area has a drop ceiling; drop ceilings are notorious for rattling with amps, regardless of acoustical fixes you might have on hand, such as bass traps and wall absorbers, and lots of studio owners simply pull them out and install something else. But doing that would put me out of business for a few weeks, and I have projects to work on. Something had to give!

    I have very good bass traps, and had good quality acoustic tiles I installed when I moved in. These ceiling tiles have a reasonable mass (mass reduces sound transmission), but they're not made to deal with the ceiling grid vibrating from SPL.

    And I did have the cabs decoupled from the floor and on risers. Both speaker cabs sit on Auralex Gramma or Great Gramma pads, and I also use an Isoactoustics IsoL8R on top of the Pads under the cab. There wasn't much more I could do to isolate the speaker cabs mechanically from the structure.

    I needed to find a cure.

    I theorized that another layer of acoustical material on top of the drop ceiling tiles above the cabs would both physically damp the vibration and absorb additional SPL. So I cranked the amp, and walked around the room while playing, noting areas where I could hear the ceiling vibrating. All but one was right over where I set up the cabs typically. Makes sense, that's where the SPL would be highest.

    As it happens, only weeks before I moved in a few years ago, a new ceiling had been installed with Armstrong 404b acoustical material.

    However, I had it replaced with better looking stuff that was maybe less absorbent, but better at reducing sound transmission due to its mass. But there was an extra unopened box of the Armstrong absorbent stuff in the storage room, that has a pretty high NRC of 0.70. That's not bad for absorbing sound. I decided to try it, as it was already on hand.

    I figured I'd simply lay it fiberglass side down, directly on top of the ceiling tiles I had installed. Easy as pie to do, though I should have worn gloves and long sleeves, I forgot how irritating that fiberglass can be if your skin comes into contact with it!

    After cleaning up the room, I fired up the amp, and played with the volume. Eureka! At normal recording levels (pretty loud!) the ceiling did not rattle at all! Much to my surprise, my theory and plan actually worked! It only rattles at ear-bleeding levels at this point.

    I figured if anyone else has this problem in their studio or music room, maybe I should share my discovery, so here it is: if your drop ceiling rattles when you play, add an additional layer of absorbent acoustical product and see if that helps.

    I'm so darn pleased with my bad self!
    Last edited by LSchefman; 07-20-2014 at 08:54 PM.
    I saw ten thousand talkers whose tongues were all broken...

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  2. #2
    A♥ hoards guitars A♥ rugerpc's Avatar
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    something else you might try is double tiling - that is 2 ceiling tiles (perhaps with different qualities) in each ceiling tile position. just the weight alone would have a dampening effect. Then you could get rid of that itchy fiberglass for when you needed to get in the ceiling to fix something....
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  3. #3
    Quote Originally Posted by rugerpc View Post
    something else you might try is double tiling - that is 2 ceiling tiles (perhaps with different qualities) in each ceiling tile position. just the weight alone would have a dampening effect. Then you could get rid of that itchy fiberglass for when you needed to get in the ceiling to fix something....
    Well, it's done now, but that would be a good thing to try, too. I do think that the fiberglass' absorbent properties and the fact that it's soft, make it a pretty good damper, perhaps in a way that maybe a harder material wouldn't be.

    These fiberglass panels were themselves designed to be ceiling tiles, so they are covered with a pebbly vinyl coating on the side that was designed to face the room. Now it's at the top of a fiberglass sandwich, which should have the effect of cutting down the dust from the fiberglass that might blow around in that space.

    I only needed to put up a few 24x48" panels to stop the buzzing; most of the ceiling doesn't have that stuff, so I'll just leave it as is for now. Taking it down and replacing it with something else would just be another itchy mess.

    At some point I may just replace the whole ceiling again with some of the newer materials that are coming on the market. If I keep the metal framed drop ceiling in place, I might just use some silicone caulking where the metal frame meets metal parts. That might also dampen and prevent vibration, but so far the improvement is enough that it doesn't seem necessary at this point.
    Last edited by LSchefman; 07-21-2014 at 11:20 AM.
    I saw ten thousand talkers whose tongues were all broken...

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    Opaque John Beef's Avatar
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    Fire up my wife's SVT/8x10 running a big muff, and all hope is lost. Our whole house shakes. Picture frames in the hallway go crooked every band practice. I have given up.
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    Senior Member sergiodeblanc's Avatar
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    Quote Originally Posted by John Beef View Post
    Fire up my wife's big muff
    Pics or it's a landing strip.

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    Name Manglin' Putz alantig's Avatar
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    Quote Originally Posted by sergiodeblanc View Post
    Pics or it's a landing strip.
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  7. #7
    Every flier needs a place to land.
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    Senior Member Michael B's Avatar
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    You rock Sergio.....crying!
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    SuperD Boogie's Avatar
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    Quote Originally Posted by sergiodeblanc View Post
    Pics or it's a landing strip.
    There are partially chewed pistachios and droplets of white wine on my iPad, currently. Well played, my friend. Well played indeed.
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  11. #11
    So back to the original non-muff stuff for a moment, turns out that once the fiberglass settles for a few days, it sounds even better than it did at first.

    The room sounds more controlled, even for singing and speech. I'd have expected less sound transmission through the ceiling, and less rattling, which is indeed the case, but the ceiling is now acting as something of a bass trap too.

    It was a good sounding room before, and it's better now.
    I saw ten thousand talkers whose tongues were all broken...

    Website: http://www.elfxi.com

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