Iso-booth: Calling all Acoustic Treatment experts

[phaedrus]

Hey all,
I am trying to turn a closet into an iso-booth--it's 4 feet by 6 feet, so it's got a fair amount of space which I'd like to use. I guess I am going for a "dead" sound--isn't that the point of an iso-booth, aside from the isolation benefit? Also, trying to do it on the cheap without sacrificing anything, though I know that's a contradictory proposition

I have read that velvet type curtains and a carpet might do the trick in that "Behind the Glass" book. Any thoughts would be hugely appreciated. Are there unforeseen problems with this iso-closet?
P

[youngmain]

Im far from an expert, but you better get lots of bass traps and make the room as dead as possible. What sucks about small iso rooms is voices will have a tendency to come out smaller sounding. I have a room that is 12'x7'x 9' walls and I feel it needs a lot of diffusion and GIk panels to get the big vocal sound Im looking for. Good Luck!

[phaedrus]

Thanks youngmain,
My theory, is that if you make the booth dead enough, the room is not a factor (no sound reflection?) and you can use a plate or plug ins to give "room" sound. This post may show my ignorance in the matter of iso booths

I have been reading this book "Behind the Glass" and some pretty heavy hitting producers (can't remember which off the top of my head) say that the whole acoustic treatment thing is overrated, and that thick velvet curtains and carpeting will do the trick and sound more "real" for tracking and mixing. Any thoughts?
P

[sonicdefault]

Phaedrus,

Is the 4x6 closet is all you have to work with? If possible, I would recommend striving to use a larger space. Unless you're going for a dead and boxy sound on all your tracks, you should make sure you have no other options. Yes, it's possible to treat such a small area, but you'll never be able to obtain the benefit of natural air which is the key to great recordings. For some styles of music it may not be such a big issue. Nonetheless, if you're aiming to take a more traditional approach towards vocal recording, you'll probably never be fully satisfied with tracks made in a closet.

One option I think is often overlooked for persons who have limited space, is to simply forget having a separate recording booth, and just put the mic(s) where you gear is. The main obstacle with this approach is usually machine noise, or outside noise. However, as far as gear is concerned, many steps can be taken to relocate the noisier equipment, or at least, isolate them within small sound dampened areas. For example... have you considered using the closet as a machine room instead? You could then use the larger area as your recording space and acoustically treat it accordingly.

Hope this helps!


-SD

[stafs]

In such a small booth, You will get much better absorptoin with DIY bass traps, made from rockwool or fiberglass. The carpet on the wall will absorb only the high frequencies, but Your worst enemy is the low's and low mids. If curtains are hanged more than half meter away from wall, then they will absorb some bass too, but Your room is too small, to waste a space. There's a lot of useful info here in gearslutz, or around the net, about bulding bass traps. And don't forget - not only walls should be treated - the ceiling also is the surface, that reflect sound waves. Good luck.

[psycho_monkey]

Have you thought about a Reflexion filter instead?

Your closet is likely to be a small boxy space. Bass treatment (and low-mid) needs space - which you don't have. The only sort of treatment you're likely to be able to fit in there will get the HF only, which will leave you with a boomy sounding space to record in.

Unless you can somehow fit the basstraps outside the closet, but with holes in the walls to allow sound into it - I'm guessing it's a walk-in type thing though, so that's probably out.

I'd suggest looking into getting a Reflexion filter (made by sE) instead.

[fross]

Isolation (on the cheap) - layers of quilted moving pads (6' x 6')
Absorbtion - take your pick (DIY or many manufacturers)

Forget about Auralex-type foam - useless, regardless of what people and brochures claim.

[sonicdefault]

The problem with trying to treat such a small room, is that by the time you are successful at dampening it to the point where it's not noticeably boxy, you've sucked all the life out of the air. You can later try to add what's missing by using eq or reverb, etc. But it will never quite sound right. Our ears are amazingly good at detecting things that are not natural sounding, and when you record in a space that's too dead, it makes vocals sound boring. Another potential problem is the increase in the perceived loudness of the noise floor. When a recording space is overly treated, the tail of the recorded signal's sustain is dampened, and therefore the noise floor more revealed.


-SD

[jowillie]

Great advice.
There is a difference between "sound-proof" and "sound dampening."
Here are just some shared unexpert thoughts.

[Ethan Winer]

Originally Posted by phaedrus

My theory, is that if you make the booth dead enough, the room is not a factor (no sound reflection?) and you can use a plate or plug ins to give "room" sound.

This is exactly correct. Small room ambience is always bad sounding ambience, so the best solution is to kill it completely. Not just at higher frequencies, but over as wide a range as possible. Even a crappy plug-in reverb will sound better than the boxy ambience in a 4 by 6 foot room like yours.

I have been reading this book "Behind the Glass" and some pretty heavy hitting producers (can't remember which off the top of my head) say that the whole acoustic treatment thing is overrated, and that thick velvet curtains and carpeting will do the trick and sound more "real" for tracking and mixing.

I think those producers should stick to writing about what they know. Curtains and carpet do not absorb nearly low enough in frequency to be useful in a 4 by 6 room. This is the same problem with using thin foam all over a room. It sounds dead when you clap your hands, but with a male voice the room resonances stick out like a sore thumb. The proper way to treat a 4 by 6 room is with good quality absorption at least two inches thick on the walls, and four or more bass traps at least three or four inches thick straddling corners.

--Ethan

[9th Ward Records]

What about these out of the box solutions?

Clearsonic Isopac E Isolation Booth