Acoustic foam is special foam that is engineered to provide the optimum amount of sound absorption to make a recording space sound better. Acoustic foam or acoustical tile is one of the easiest and most cost effective ways to retrofit a room with acoustic material to improve the recording quality of the room.
All rooms have inherent acoustical problems, such as standing waves and room modes. Without getting technical, this has to do with the shape and size of the room, as well as what is on the walls. Suffice it to say that these problems can negatively impact the sound of your recordings.
Any room will benefit from some acoustic material, in whatever amount you can give. You can do this in several ways. First, you can put some acoustical foam on some walls to cut down on the extra reverb or nasty slapback echo. Second, you can use a bass trap to level out the room’s response, and make the whole spectrum more accurate. And lastly, you can put some other acoustic material, such as a diffuser, on the walls or ceiling to further diffuse and scatter the sound.
All these things will make the room sound much better for recording, because the echoes and inherent problems are being taken care of.
The sound of the room dramatically impacts what kind of recording you will end up with. Think about the difference between a bathroom and a gym. Huge difference, right? Maybe a more fair comparison is a a tub/shower and a walk in clothes closet.
The tub, because of the hard surfaces and small area, is much more “live” and reflective than the closet. However, the closet still doesn’t mean that recording will be fine. Because of all the clothes and carpet on the floor, it tends to absorb high frequencies. Low frequencies bounce around, untouched by what is there.
If you do a recording in one of those rooms, you may get your desired response, but usually it won’t be. It may be:
(Actually, you can test that in a shower – just hum or sing up in pitch like a siren from your low range, and listen for which note jumps out at you.)
This is why you need acoustic treatment.
There are two basic kinds of acoustic foam that I recommend getting. First an acoustical tile, or a small tile that you can fasten to the wall. Auralex is a company that makes these, and here is what they call a “wedgie,” a 2’x2′ piece of acoustical foam. They have various kinds of foam, and I use two different kinds in my studio. While you’re on that site, do a search for Auralex, and see what else they have available.
The second kind of treatment I recommend is a bass trap. This is simply a piece of engineered foam that you put in the corner of a wall. These corners are typically the place where low frequency pockets congregate. Just try humming some low notes, and move toward a wall corner. What makes it worse is that these low frequencies are the hardest to control. That’s why Auralex has a such great product in their LENRD bass traps. I use them in my studio, and they work wonderfully.
The last main kind of acoustic treatment is one that many people won’t need to use. It is the diffuser. If acoustic foam absorbs the sound frequencies and stops them from reflecting, a diffuser reflects as much of them as it can. But instead of reflecting everything the same way, like a wall, an acoustical diffuser tries to do this as randomly as possible. This way the higher frequencies are reflected and distributed in the room. The result is a more even room.
Installation of these materials is fairly straight forward. You can permanently adhere it to the wall with glue ( TubeTack that comes in a caulk tube, or Foamtak that comes in a spray bottle and is easier to use). The diffusers require a bit more work, like stuffing the back with insulation for extra benefit, and using contact cement to glue it to the wall or ceiling.
So, outfitting a room for better acoustics for recording isn’t hard. Some simple acoustic foam will get you well on your way.