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August 17, 2009 12:19 PM   Subscribe

How do I improve the acoustics in a room not really cut out for recording?

I want to do some recordings in my home, preferably in my bedroom. It's not the best venue for the task, though, as the wide expanses of drywall make for a lot of echoes. Are there any easy ways to make an area where I can record without extraneous noise? I don't know if it's relevant, but I will be using a condenser mic with cardioid directionality to record voice and instruments.
posted by invitapriore to Media & Arts (7 answers total) 4 users marked this as a favorite
 
don't fall for the egg crate thing, make your own bass traps from plans that are easy to find on the internet. you can hang some drapes if you really want to deaden the high end, but i'll bet it's not as big a problem as you think. beyond that, you'll have to expand on what you think is "extraneous noise."
posted by rhizome at 12:30 PM on August 17, 2009 [1 favorite]


Acoustically treating a room is tricky, and will be completely different from room to room. It would be easier to take the room out of the equation, or minimize it to some degree. To this end, covering the walls with curtains can really make a difference. What you're hoping to do it take all or some of the of reverberance out of the room, so you'll know you've done enough when the room sounds "dead". With a cardioid mic, you might be able to get away with treating a corner of the room, and aiming the null point in the mic's pattern into that corner. I'm assuming you are close micing. If not...

To properly acoustically treat a room, you'll want to start with injecting pink noise into the space, and measuring the levels in all audible bands. Based on the measurements you take, you can being to start treating the room. What you end up with is a "live" sounding room with good reverberance. There are kits that you can get to do this, but you'll need to start with measurements first in order to know what to get.

Either way, good luck!
posted by c*r at 12:41 PM on August 17, 2009


Yeah, for the most part, don't sweat it. That egg crate stuff is super-flammable and doesn't work so well anyhow, so definitely stay away. Like rhizome says, bass traps are probably a good idea, but depending on the size of the room and what type of stuff you're recording, they're probably not necessary for tracking. If you're mixing in the room, though, treatment is more important (I'll make an embarrassing admission: I don't bother with any kind of treatment in the room I record and mix in; you get used to it).

If the room really is super pingy, though, find a spot that's not (there's usually a sweet spot, even in a bad room). Or hang some blankets in the corner and record facing them (sound source aimed at the deadened corner). Unless you're recording very quiet acoustic instruments and trying to capture a lot of room, though, it's not a very big deal.

You might want to try using a dynamic mic instead, though, in a too-live room, particularly on vocals.
posted by uncleozzy at 12:46 PM on August 17, 2009


There is a difference between sound proofing and removing echos. It's hard to stop sound from getting out of the room it's a lot easier to cut the amount of audible echo in a room.

The room we practice in has a lot of high pitched echo so we put moving blankets up on the walls. This cut a down a lot of that. Soft stuff like blankets, foam, and pillows really help cut the amount of mid to high pitch echo. For bass you should look into getting/building bass traps.

If you are recording vocals or acoustic stuff one instrument at a time go with a vocal screen or booth. A cheap way to do that is get or build a folding set of panels, (think the Asian screens people change behind or decorate with) and cover it in a non acoustically reflective material. Then surround yourself and the mic by the screen when you record.
posted by magikker at 1:02 PM on August 17, 2009


Is the problem reverberation or noise? This is what I have done when I want a room to be livable and still sound ok for recording.

First, noise. If there are things inside the room making noise, move the offending object out of the room, turn it off (HVAC too), etc. If the noise is coming from outside, sealing the room well is your first best option. Even very small air paths transmit more sound than you would imagine. Weather stripping and foam for sealing is your friend here.

Now your room is quiet, but it still sounds like crap. To treat reverb problems, you need fuzzy stuff in the room. Do you have carpet? If not, get a thick rug in there. Do you have a window? Glass really reflects sound, so putting up thick curtains can make a big difference. Take your mattress off the bed and lean it against a wall. Get a big leafy plant, and put it in the corner. Hang a thick tapestry on the wall. Put a big bookshelf with books in the room. Get a big bean bag and set it in a corner. Anything that reduces the "empty room" echo when you clap helps.

If you have a budget and the ability to modify the room, you can start getting foam and such, but generally it is better spent getting a few hours in someone else's studio.
posted by cjemmott at 1:05 PM on August 17, 2009


There are two things that can help a room sound better (although it won't help with sound getting out of the room, so it doesn't apply to soundproofing). Diffusion and absorption.


Absorption is going to be more important for you. You want to absorb as much of the sound bouncing around the room as you can. If you have nothing in there right now, carpeting and drapes will help somewhat, but they don't do anything to absorb low frequencies. This will make your recordings sound "muddy". You might be able to get away with that, but if you want things to sound "good", instead of just sounding better than they are now, you will need to work on reducing the low frequencies.

Bass traps are designed in many different ways, but the simplest ones are just a very dense breathable material (most people use compressed fiberglass), with an air gap between it and the wall. If you have a 4 inch thick slab of rigid fiberglass, and you space that 4 inches from the wall, it is almost as effective as an 8 inch slab of fiberglass directly attached to the wall.

If you can find a supply store that sells rigid fiberglass panels, get some of those, cover them with a breathable fabric (burlap is used sometimes, I used a cheap weed block fabric that I had a bunch of), and mount them in the following places:

1 - On the walls directly in front of the mic, behind the mic, and to the sides of the mic. If you were to stand where the microphone is, and placed a mirror flat against the wall, anyplace where you can see your face reflected, that is where the panels should go.

2 - On the ceiling directly above the mic

3 - As many corners where two or more walls meet. Bass concentrates in corners, so if you can place these panels at an angle over the corners, they will be much more effective in general absorption than if they are on the walls.

4 - Everywhere else

Depending on what your budget is, that will determine how well things are going to sound. The important thing is to always remove the direct reflections first, and then work on treating the rest of the room. If you are going to be having the mics in more than one location in the room than you are going to have to compromise.

Big pieces of furniture will help, as well as anything with a lot of softness to it, as long as it is breathable. If you put it to your mouth and can blow air into it, it will work. If not, than it will not absorb as well, and will be less effective.

If you can't afford any real acoustic material, you can also get regular fiberglass rolls, and put those around the room. Don't unroll them, but cut open the plastic and wrap them in fabric. You can make little columns with these in the corners for bass traps.


Diffusion will also help, although most likely not as much. In essence you want to make the sound waves break up and bounce randomly around the room, to prevent any specific frequencies from building up. Book cases filled with lots of different sized books to this fairly well (and books also have a small degree of absorption). A cheap and effective diffuser is easy to make. Just take a panel of plywood and squeeze the ends together so that it curves. Put it against the wall so that it bows out from the wall, and attach the two sides so it doesn't move. Fill the back with absorbing material to keep it from resonating. That is a simple fix for slapback echos, and if you put enough absorbing material behind it and leave a gap around the sides, top, or bottom, it will also help in absorbing some of the lower frequencies.

I am a firm believer that acoustically treating your room will make a bigger difference in your recordings than buying an expensive mic, preamp, or monitors. If you are both recording and mixing in that room, treating it correctly will help you twice.
posted by markblasco at 3:19 PM on August 17, 2009


Thanks, everybody. You all mentioned different and useful ideas so I marked them all as best.
posted by invitapriore at 6:01 PM on August 18, 2009


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