In the beginning, there was perfect sound…then man invented rooms and messed everything up. The end? Luckily, no. It’s been said that the perfect recording environment is the great outdoors. But since that’s not feasible, the next best thing is to acoustically treat our rooms so that they don’t mangle the sound we record and/or listen to.

Sound Waves

Sound waves generated in a room radiate out to the room’s boundaries, are reflected and then interact with each other, much as do ripples in a pond. Visually the effect can be mesmerizing; aurally the effect is guaranteed to be undesirable. There are three types of sound wave reflections. They are axial, tangential and oblique modes, which relate to which direction in a room sound is being reflected from one hard surface to another. The worst of these types is the axial mode, which means sound is being reflected from wall to opposing wall or floor to ceiling. Corners cause a lot of problems, too, boosting the apparent amount of bass in our rooms by 9dB, making us think we have 3 times as much bass as we actually do.

It is for this reason that the field of acoustics has become so important and why some acoustical consultants are literally paid millions of pounds for their work on single projects. But how do we accomplish this sound control that is so vitally important? Generally, by means of absorption and diffusion of the sound waves generated in the room.

Choices In Methodology

While some believe that making a room’s surfaces totally absorbent or totally diffusive is the only way to make a room sound “good,” this is most often not the case. While it’s true that some rooms’ acoustics are best controlled exclusively with specific types of treatments, the really great sounding rooms tend to be ones with a proper blend and placement of absorption, diffusion and low-frequency control.

Often, these rooms exhibit a pleasing degree of natural ambience with no flutter echoes or false bass buildup that could color the sound being recorded or monitored.

Many people like diffusion on control room rear walls. However, if your situation dictates, we have other products like TruTraps Broadband Absorbers which look great, absorb really well overall and allow you to gain significant sonic control (especially in the low-frequency department) without excessive dryness.

On the other hand, there are places like radio studios and voiceover booths where a very dry, controlled environment is definitely called for. Drying these rooms out ensures that when a talent is speaking into an open mic, all you hear is an up-close, direct, present sound, not a bunch of detrimental room ambience. Listen to network-quality voiceover work on commercials, movie trailers and the like, you virtually never hear the “room.” If you desire liveliness in your performance space, it must be:

1. Well-controlled in order to sound pleasing and professional
2. Appropriate for your space’s intended use.

How Dry Is Dry Enough?

Many standard rooms’ acoustical needs can adequately be provided for by periodic (spread) absorptive treatment. For those of us who:

1. Don’t understand the intricacies of ‘tuning’ a room or
2. Don’t have the budget to really go the extra mile, this is good news!

The BBC studied the effects of spreading absorbent materials around a room instead of putting all the materials on one room surface and found that spreading the material around almost quadruples the amount of absorption! This is why we often recommend cutting our 2’ x 4’ Studiofoam panels into 2’ x 2’ sections and spreading them apart on the walls and ceiling. Rooms treated this way tend to have pleasing, well-controlled sound without being perceived as too dry.

Choices In Material

The two most common absorbent materials are high-quality acoustical foam  and specialized acoustic fiberglass. For brevity, at times we’ll generically call acoustical foam just plain “foam”, although there are very dramatic differences in cell structure and density between acoustical foam and the thousands of other types we could manufacture. (This is why you can’t just run down to the local Super Market and buy mattress pads with which to treat your studio.)

Acoustical foam is well-suited to alleviate slap and flutter echo, the two most common problems in rooms not specifically designed for music recording and performance. In fact, properly placed and chosen acoustical foam can turn even the most cavernous warehouse or gymnasium into a suitable acoustic environment.

You’d be amazed if you could see—and hear—what some of the spaces used to record CDs, commercials and movie soundtracks would look and sound like without acoustical treatments.

Features and Benefits

Foam is easy to work with, simple to trim to size and costeffective for virtually any budget. Foam will improve the sound picked up by your microphones and give you a more accurate monitoring environment, thus ensuring your recordings will sound better (“translate”) wherever they’re played.

In a listening or viewing space, foam allows you to hear recorded works the way the artist intended without your room detrimentally modifying the sound. Foam makes your environment more comfortable to be in, so you’ll find yourself being more productive, at ease and creative, and in general, reaping more enjoyment out of the space.

Most people report much improved concentration and hearing acuity in welltreated spaces.

Many Options

Foam is available in a variety of thicknesses. Which size is correct for your particular room is determined by a variety of factors, including: room size and placement of monitors, types of sound being generated in the room, ceiling height, the materials used to construct the room and its surfaces, the amount of glass in the room, whether there is carpet on the floor (and over what type of pad it’s installed) and other factors, not the least of which may be budget.

Based on physics, the thicker the foam, the greater the amount of overall absorption, but especially toward the low end of the frequency spectrum. The most common thicknesses of acoustical foam are 1”, 2”, 3” and 4”. Auralex also has proprietary foam bass traps that are easy-to-install, more affordable than you’d think and phenomenally effective.