A few design questions....

A

Amateur Eric

New member
Greetings...

I'm in the process of changing my 9'-8" X 12'-8" bedroom from a music/practice room into a recording studio. My primary uses will be instrumental practice, arrangement and recording of music( blues, rock and contemporary christian) as well as making vocal accompaniment tracks for singers and the occasion demo and or writing attempt. I just finished removing the acoustic texture yuck on the ceiling and replacing it with textured drywall mud.

The next step is acoustics. Since I'm stuck with the rectangular shape I've looked at several acoustic treatment companies. One that peaked my interest is "Acoustical Interiors" (www.sysdevgrp.com). They have a room "kit" for a 10 x 12 room that runs from $500 to $800 and looks like it makes sense. But since I don't have a degree in acoustical science (come to think of it, I don't have any degree... "D'OH!") I'd like the opinion of others.

Also, Should I replace the old carpet with new carpet or could I put a laminated wood product in there? Would hard surface flooring cause too many problems in such a small room?

Thanks in advance for your input

Eric
 
I'd go with the wood floor - carpet sucks out too many of the highs without affecting lower frequencies. Then you could put broadband absorption material on the ceiling instead, adding wall absorption only where necessary. If possible, you want your speakers away from the wall by a foot or two, more is better, and the whole room symmetrical on either side of a vertical plane that passes thru your head and equidistant from the two speakers. In other words, whatever is on one side should also be on the other, when you're looking at a point halfway between the speakers. This affects how you mix, and can change the stereo balance in your recordings (not in a good way)

One of the easiest ways to decide where to put absorption is with a friend and a dressing mirror. You sit at the mix position, and the friend moves the mirror around, holding it flat against the walls/ceiling, and anywhere you can see EITHER speaker in the mirror should have absorption. After that, it comes down to how much reverb you want, which in a small room won't be much. The wall behind you when you're listening to the speakers, especially in a small room, should be pretty dead. Reflections coming back from behind you will muddy the stereo image.

The cheapest and best absorption is the RIGID fiberglas boards sold as Owens Corning type 703 or 705 - Knauf company makes a similar product, it should be 3 pounds per cubic foot density. This is COMPRESSED fiberglas, not the fluffy stuff - that's why it is semi-rigid. It needs to be covered in some kind of cloth so it won't shed fibers.

The tricky part is finding someone who will sell it to you, since it's generally only used commercially. People have had the best results in the Yellow Pages, looking under commercial Insulation Contractors. Some contractors will sell you a few pieces (usually comes in 2 x 4 foot pieces, in thickness from 1 to 4 inches. 2 inches or 3 inches works well, 4 if you have the room. The thicker, the lower frequencies it works at. Standing it off the wall helps lower the effective frequency even more.

Costwise, if you can find the stuff it is about 1/5 the cost and at least twice as effective as the commercial so-called acoustic foam - that's why most of the people here spend the time to find it locally instead of paying several hundred dollars more on the foam kits... Steve
 
Thanks guys

Okay,
I went to the SAE websight and punched in the variables including windows and light weight drapes I'm going to put up in place of the sliding closet doors (I figure I might get rattles out of the closet doors and drape with cloth loops instead of plastic or wood will be quiet). I did it first with carpet over concrete, then with wood flooring (I'm hoping this is the same whether its on a concrete slab or wood sub floor). I noticed the overall reverb times were about correct for the carpet with the exception of a balloon figure at 250Hz. The wood floor was much higer but a flatter response over the whole band width.
So am I correct in understanding that it will be easier to find the materials to compensate for the more even (high end accentuation) reverb time without having to deal with "just a balloon shape at 250Hz?
If thats the case, wow. And here I thought even the slightest knowledge of acoustics was going to be over my head. Of course, if thats not the case... "D'OH!"

Any other idea's or precautions?

Thanks again
Eric
 
If those figures were not including any absorbent on walls or ceiling, then you will probably be good with some 2" 703 over the mix position, and spot treatments where the mirror tells you. You might want to tweak a few things after that, but probably not much.

Did you take into account the mid-bass trap action of sheet rock on stud walls ? That will pull the low mids down some as well... Steve
 
Big Thanks

Thanks for your insight,
Okay, gonna go buy some Pergo flooring and see if I can find some of that rigid fiberglass insulation. As soon as I can get it done I'll let ya know how it turns out

Eric
 
Knightfly,

Could you go into the bass absorbtion factor of sheetrock on stud walls? I have all sheetrock/stud walls in my control room. What will this do for me? See this diagram if necessary.

http://www.geocities.com/booksixstudios/Diagram2.jpg
 
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