John Sayers' Recording Studio Design Forum Archive

Hello, I'm an actor with very little knowledge about acoustics and sound aside from what I've been reading on this forum for the past few days. I have a converted garage that I had been using as a storage area and also for video taping my auditions. It worked well enough for my auditions until I recently cleaned all the junk out of it to make the space usable as an art studio as well as audition room. With all the stuff cleared out I now get a boomy echo sound when I record auditions. For my auditions, I need the sound quality to be decent enough that it is not distracting to the viewer.


PURPOSE- To be able to record flim/tv auditions without an echo/reverberating sound.

ROOM- This is a converted garage. Walls have been covered with drywall and I believe there is old fashioned fiberglass batting between drywall and frame. The floor is bamboo. The room is 15' long It's 14' wide for most of the room but there is a 5' x 2' corner that juts in (bad description but please see drawing/photo. The room is 7 feet high. There are two skylights, one in the middle is 17' x 44' and height from the floor is 8.5'. The other skylight is 18" x 18" also 8.5" from floor. One of the 14' wide walls has an 8 foot sliding glass door.
After my recent experience with the echo in my audition I bought a 5 x 7 rug and put it in the middle of the room. And covered furniture with blankets and fabric. This helped and got the sound quality back to close to what it had been before I cleaned out the space. However, I don't want to have to have blankets draped over everything all the time and am looking for a more permanent solution.

LOUDNESS- I don't have a decibel monitor so it's hard for me to say exactly. Most auditions are done with a normal speaking voice but occasionally I need to yell and that does tend to create more of an echo
There is no issue with neighbors or others hearing the noise. My only concern is the quality of the recordings.

LIMITATIONS- I have chemical sensitivity issues and want to avoid using fiberglass panels just in case they trigger my issues.

BUDGET- $200

GOAL- To get rid of the echo without altering the space and still have it be usable as an art studio / guest room.

CURRENT PLAN-
1. I am making a 6' x 4' canvas and painting it middle grey to use as a backdrop for auditions. I was planning on putting 12 Auralex 1' x 1' x 2" foam wedges beneath the canvas . I was going to stick 12 on in a checkerboard fashion so that there are 12 ft covered in foam and 12 feet empty. I was then going to put three more wedges under canvas on the opposite wall.
Someone on Craigslist has 45 panels for $100 so I was going to buy those.

QUESTIONS

1. Is there a simple way of limiting the echo in this room?
2. I have seen a lot of people on the forum saying that acoustic foam isn't really useful. I am wondering if I'll be wasting my time/$ with getting the foam and putting it on the canvas.
3. Will having the foam behind the canvass lessen the effectiveness of the foam?
4. Would perhaps just putting the 6' x 4' canvas on one wall and three or four 2 ' x 2' canvases on the opposite wall alone (without foam) help my cause?

Thank you.

High there "auditioner", and Welcome!

With all the stuff cleared out I now get a boomy echo sound when I record auditions.

Yup! The typical sound of an untreated room, which is rather unpleasant, and definitely no use for auditions.

The room is 15' long It's 14' wide ... The room is 7 feet high.

That would place most of the modal issues around the sae frequencies, because the dimensions are all similar. Certainly the modes related to the width and height are going to coincide exactly, since the 14' width is exactly twice the 7' height. And the 15' length is not a lot different than the 14' width. Thus, our boomy sound is going to be concentrated around the frequencies related to those dimensions.

After my recent experience with the echo in my audition I bought a 5 x 7 rug and put it in the middle of the room.

Rugs and carpets don't do very much useful for a small room: In fact, they do pretty much the opposite of what is needed. Carpets and rugs are very thin, so the can only affect the high frequencies, maybe something in the mid range, but nothing at all in the low frequencies. But small rooms need the opposite: they need extensive treatment in the lows, some in the mid range, and almost nothing in the highs.

And covered furniture with blankets and fabric. This helped and got the sound quality back to close to what it had been before I cleaned out the space. However, I don't want to have to have blankets draped over everything all the time and am looking for a more permanent solution.

Here too, the blankets are thin and won't have much of an effect on the real problem; low frequencies. They work better than te rugs, for sure, because you have the draped over furniture, which creates an air space behind them, thus increasing their effect down to lower frequencies. But they still don't go ow enough. And as you say, you can't have your furniture covered with blankets!

LIMITATIONS- I have chemical sensitivity issues and want to avoid using fiberglass panels just in case they trigger my issues.

Fiberglass itself is inert: after all, it is just glass! The problem is the binders that the manufacturers use to make the fiberglass products. Some of those do indeed contain nasty chemicals, so it's important to check what they actually use. One such chemical is formaldehyde, which was commonly used in many insulation products. But these days, most manufacturers are moving away from using formaldehyde and other problematic chemicals, and are no using far more benign binders. However, there's still a lot of bad stuff around, so do check the specs for what ever product you are interested in.

Also, typical acoustic treatment for rooms like yours can be wrapped in plastic to completely seal it off from the room air, so it would not affect you at all.

But if you still don't like fiberglass after all that, the only other real option available to you is mineral wool. The Rockwool company, (aka. Roxul in some places) has several products that would work for your room.

I was planning on putting 12 Auralex 1' x 1' x 2" foam wedges beneath the canvas .

That's way too thin to have any useful effect. With your dimensions, your room is going to have major problems around 40 z, 70 Hz, 80 Hz, 113 Hz, 150 Hz... and in general, everything below about 300 Hz. In order to be effective, the absorption needs to be at least 1/16th wavelength thick, for complicated acoustic reasons. The wavelength for 40 Hz is 28 FEET! As you can imagine, 2" of foam has zero effect on a wave 28 feet long. To be effective, you would need absorption 23" deep... Sad, but true. However, the treatment does not need to cover the entire wall that deep! There's a type of treatment device that you can build yourself, called a "superchunk", which is basically just large triangles of mineral wool stacked up in the room corners, floor to ceiling, with a fabric cover to make it look nice. If you search the forum for "superchunk", you0ll find many examples. You could make your triangles 24" along the sides, and you would be getting very useful bass trapping. Do that in two or three corners of your room to start with, then see if you need to do more.

In addition to that you will need something for the mid range, and that can be done with mineral wool panels about 4" or 6" thick, hung on your walls. It's easy to make simple wood frames from 1x8 wood planks (for 6" panels) or or 1x6 (for 4" panels), then put a half panel of mineral wool in the frame and cover it with nice fabric. Mineral wool usually comes in panels that are 4' x 8', so you can just cut those in half to make 4' x 4' panels for your walls. Probably half a dozen of those would be enough for your room. Hang some of them higher up near the ceiling, some near the middle of the room height, and others lower down near the floor.

That should tame the room enough to be able to do auditions. If you find that the room now sounds too "dead" and "dry", then you can add a bit of life back in again, by either putting plastic between the mineral wool and the fabric, or by putting wood slats across the front, with large gaps between them. In fact, you can sort of "tune" the acoustic response like that, by using different width of wood slat and different spacing, until ti sounds hte way you want it.

You will probably also need something on the ceiling, at a few points, but it can't be very thick because the ceiling is low. There's a couple of options there, but try the above first, then let us know if you still have some unpleasant sound in there, which will be from the ceiling. Then we can help you fix that too.

Someone on Craigslist has 45 panels for $100 so I was going to buy those.

Don't waste your money. 2" thick foam of unknown origin isn't going to do much, even if it is great quality. And 1' x 1' panels are not nearly enough to be useful.

2. I have seen a lot of people on the forum saying that acoustic foam isn't really useful.

Right! very true. Look around at some pictures of professional studios: how many of them do you see with foam on the walls? There's your answer. If the pro's don't use it, then clearly it's not much use.

I am wondering if I'll be wasting my time/$ with getting the foam and putting it on the canvas.

Definitely!

3. Will having the foam behind the canvass lessen the effectiveness of the foam?

Not really, because the foam doesn't have much effect anyway! So if you start out with "nothing", then reducing that doesn't make much difference...

4. Would perhaps just putting the 6' x 4' canvas on one wall and three or four 2 ' x 2' canvases on the opposite wall alone (without foam) help my cause?

The canvas would so something, but probably not what you need. IT will act something like an acoustic membrane trap, which is tuned to one specific frequency and can absorb just that frequency... but nothing else.

So that's what I would suggest. Forget the foam, and build your own treatment from simple stuff you can buy in any hardware store. Inexpensive, yet effective.

- Stuart -