Rookie question: How to finish walls/ceiling/floor

[sauceman]

This question is coming from a rookie builder!
I am just finishing a small (~8X8) practice room in my basement. It is sufficiently soundproofed or isolated from the rest of the house, but now I need to know what to put on the walls for sound absorption.

- The room will be used for drum practice
- It does NOT have to have recording quality accoustics
- The solution should be as cheap as possible
- The walls and ceiling are now just drywall
- The floor is concrete (but I was going to put carpet on it)

The goal is to achieve sufficient sound absorbtion, but I don't know if there is such a thing as overkill on this. Can a room be too dead? Should I cover all the surfaces in something like ceiling tiles? Cloth? Slats? Should I leave some of the wall surface untreated?

[knightfly]

You may decide later that you want to record there, so I wouldn't put carpet on the floor. Vinyl is as cheap, and better acoustically. Walls and ceiling should be absorbed, although you'll get a more live sound if you leave two adjacent walls painted and the other two absorbed.

If you can find either Knauf fiberglas or Owens Corning 705 semi-rigid fiberglas insulation locally, that would be the thing for ceiling and two walls. 2" thick, spaced off the walls by 2-3 inches, will work well.

The best places to look locally are COMMERCIAL insulation/drywall contractors - call all of them in the book, some will help and others are assholes. Manufacturers won't sell in small quantities so if you can't get it locally you almost can't get it.

If you do find rigid fiberglas, it needs to be contained so the fibers don't irritate - you can wrap it in one of those super-thin painter's plastic drop cloths and then use your favorite cloth over that. Just don't glue it to a piece of plywood, or spacing it off the walls won't help low frequency absorption.

If your ceiling is also 8 feet, you'll have a nasty ring at around 70 hZ and all multiples on up to around 400 hZ - two of these, the 280 and 350 hZ, will LOVE your kick drum. You might find that you're willing to build a tuned slot absorber for one corner to get this under control. We can help there too... Steve

[sauceman]

Thanks for the quick reply! I never conisdered vinyl for the floor, but I'll try it out.

If I can't find the type of fiberglass insulation you mentinoned would those fiberglass ceiling tiles do? Do you know the ones I mean? They're semi-rigid yellow fiberglass with a thin, bubbly, plasticky coating on one side. They're designed for use in a suspended ceiling? They have the benefit of not having to be covered.

I've attached a rough sketch of the room. As you can see I actually have one 'wall' which is actually a curtain, so should I treat the wall across from it and leave the two side walls untreated?

[AndrewMc]

I know the type of tiles you are talking about - Armstrong makes them. They are rigid fiberglass, but they are only about 3/4 inch max. You could double / triple them up but it might end up being costly.

[knightfly]

First, be careful what you buy at Home Depot - some of the "yellow stuff" they sell is really rigid FOAM, and closed cell to boot. Good for heat insulation, NOT good for sound absorption.

I'd start by just treating the left side wall (as the pic is oriented - see if it's enough combined with the curtain (no mention of how heavy this is, but usually only good for high frequency absorption) - It's easier (and cheaper) to ADD treatment later than to REMOVE it if it's not needed.

You WILL want to do the ceiling though, keep looking for the real rigid fiberglas in at least 2" - if your local commercial insulation/drywall places don't have it, then you could try some of the yellow stuff - but without a better description, I'm not sure what you're looking at... Steve