Using ceiling space as a bass trap

beggehorn · Post by **beggehorn** » Tue Aug 26, 2003 5:29 am

What a great site! Its timely that I stumbled across this site as I'm just about to begin a long overdue acoustic "makeover" at my studio. I recently had a local acoustic consulatation firm come in and give me their opinions and advice on making some improvements in my space. I have a modest production studio in a converted garage with two adjacent "rooms", each about 7'x8' with ceilings that angle up from 8' to about 11' or so. I was told that the extra ceiling space would serve as very effective bass trapping for combatting the buildup of low to low-mid's I experience in those small spaces. The plan is to drop the ceiling to 8' with a 2x4 frame, lay some thick insulation in the space on top and then install a fabric "ceiling" to contain the fiberglass but allow sound to pass unimpeded. It seems simple in theory but I'm having a tough time visualizing how to create a fabric ceiling that will go wall to wall and look like I knew what I was doing. I guess I'm trying to avoid grabbing the staple gun and going around the edges with it. Anyone have any experience or suggestions for this one?

knightfly · Post by **knightfly** » Tue Aug 26, 2003 6:44 am

First, you want rigid fiberglas or rockwool/mineral wool insulation, the more the better - see the materials forum for source suggestions -

Second, you need a fairly substantial (but not too close-weave cloth, and stapling works fine. You may need a helper, but you want to stretch the cloth enough to avoid sagging.

If you like, you can put thin lath strips over the staples and fasten them with small screws for better support and a more finished look (paint or stain them to taste)

Doing that should help your rooms quite a bit... Steve

beggehorn · Post by **beggehorn** » Tue Aug 26, 2003 11:32 am

That sounds great, thanks for the tips! I was actually told to place R-30 insulation above the ceiling joists I'm installing, which comes in batts not rigid form. I've seen false wall/bass traps that use the thick puffy stuff in the trap and am assuming that this design will be similar.

beggehorn · Post by **beggehorn** » Tue Aug 26, 2003 11:34 am

btw, any leads on a Guilford-type material that has the look without the price?

laptoppop · Post by **laptoppop** » Wed Aug 27, 2003 12:01 am

You might want to consider another option -- building a "drop ceiling" using tiles of rigid fiberglass insulation. 4" thick of that stuff with an air gap between it and the real ceiling is darn absorbent!

For my studio, I made tiles - 2'x4' and wrapped them in muslin cloth - muslin is about as cheap as you can get. I got the natural, unbleached kind. You can get it bleached or unbleached, and dye it to any color -- or some places sell it colored already.

For pictures of what I mean, check out update 1 for laptoppop's studio in the studios under construction section off of John's main page.

I wrapped the fiberglass up like a present, and used hot glue to hold the fabric together on the edges.

Just a thought. From what I understand, the rigid fiberglass absorbs sound much better than the fluffy stuff.

-lee-

knightfly · Post by **knightfly** » Wed Aug 27, 2003 1:52 am

Lee's right, the rigid stuff is several times better for bass traps. The whole idea of bass traps is for the "interstices", or threads, of fiberglas, to impede the movement of the sound wave through the insulation - the more of these there are, up to a point, the better the absorption. The rigid stuff is several times as dense as the fluffy stuff, hence the difference in absorption... Steve

beggehorn · Post by **beggehorn** » Wed Aug 27, 2003 10:10 am

Thanks Lee & Knightfly. Lee, those pics look exactly like what I'm trying to pull off only on a slightly smaller scale. I like the ideas of a simple "tile" layout. You guys are great...kind of wish I had found this site before I spent the dough on the consultation...

beggehorn · Post by **beggehorn** » Sun Sep 14, 2003 3:46 am

Just one more question on this topic:

Do I leave the real ceiling (above the dropped one) untreated, or is it a good idea to fill that area or line the ceiling. One of the two rooms has 4" foam completely lining the walls (above 8') and ceiling. Should this come down or will it help the cause?

knightfly · Post by **knightfly** » Sun Sep 14, 2003 9:19 am

If you do a dropped ceiling using rigid fiberglas, the foam is kind of a moot point (above the fiberglas, that is) you can leave it or lose it, it might make maybe 2% difference if that. I'd take it out if there was any chance it's NOT fireproof, or if you have any chance of a rat/mouse infestation in the future

... Steve

beggehorn · Post by **beggehorn** » Tue Sep 16, 2003 2:57 am

Thanks again for all the help even with your busy schedule. I'm starting this project today, wish me luck.

knightfly · Post by **knightfly** » Tue Sep 16, 2003 3:22 am

OK, luck Ben - And thanks for your concern - fortunately, yesterday was the last "extra" night shift for a while, so I should be able to breathe without a schedule check.

I don't mean to sound like I'm too busy (or too important) to help; those comments were only intended as explanation for not getting back with answers as quickly as I wanted to, nothing more.

If you have any doubts about ways of doing any of your impending steps, please don't hesitate to ask... Steve