The Importance of Acoustic Treatment

Disclaimer:

Please understand first of all, that acoustic treatment, as described here, is designed to control the sound quality within a room. It is not, however, intended to prevent sound propagation between rooms or to be construed as a soundproofing material.

There’s been a little bit of chatter lately about acoustic treatment and whether or not it makes a considerable difference. This tip may help you to re-define your opinion of it if you’re a beginner in the think it has no impact, as veterans may find it a bit beneath them.

Why should I acoustically treat my recording area?

There are four primary goals of acoustic treatment: 1) To prevent standing waves and acoustic interference from effecting the frequency response of recording studios; 2) to reduce modal ringing in small rooms and lower the reverb time in larger studios, churches, and auditoriums; 3) to absorb or diffuse sound in the room to avoid ringing and flutter echoes, and improve stereo imaging; and 4) to keep sound from leaking into or out of a room. That is, to prevent your music from disturbing the neighbors, and to keep the sound of passing trucks from getting into your microphones. Yes, it's true! Not only can a room’s acoustics affect your recording, but it can also have an impact on how much sound is transmitted from and/or into the room. This is why it's important to employ some form of acoustic treatment; to protect the sound you're working so hard to create.

Once the sound is transmitted into your room, you’ll have two main considerations to address: absorption and diffusion.

Diffusion

Dedicated diffusion panels will help to diffuse waves which might otherwise be bouncing around the room and cause early reflections and phase issues during critical listening periods and recording sessions.

Bass Absorption

The thicker and more solid the walls are, the more likely you are to get a problem with bass frequencies (something to be aware of when soundproofing). Reverberation, the 'dying away’ of a sound, is natural to music. Most music is designed to be performed in a reverberant space - military band music being an obvious exception. When you make a recording, you need to be able to judge how much reverberation is on the recording. Excess reverberation in the room will colour your judgment. Another problem with reverberation in the studio control room is that the frequency response of the room itself may not be flat. More than likely, there will be more reverb at bass frequencies. This will make you think that a recording is more bassy than it actually is.

So where do I start?

A rule of thumb in basic acoustic design is live-end/dead-end. If you look around your room and all the walls have hard, live surfaces — that's going to contribute greatly to a "boxy" sound. Pick a wall, whatever you might call the "front wall" and put absorbing material on at least 50% of the wall — especially in the middle section. The "material" could be anything from blankets to egg cartons to mattresses to carpet padding to bed padding to acoustical foam. One option I'd recommend is something like Sonex Classic. You can buy 2" x 2' x 4' Panels. They come eight sheets to the box for $169, which covers 64 square feet. For a dirt cheap bass trap, I’d recommend the Auralex 2” corner fills, which can be found by clicking here.

All this takes a little bit of money and a bit of time and tweaking, but considering that the room is really the most important source of how everything recorded in it will sound — it's worth spending a couple of hundred bucks [or less] and part of a day to get a good-sounding room.

You’ll thank yourself in the long run, and your end product might reflect your efforts, perhaps literally. Happy recording!