A beginner’s guide to acoustic treatment

It doesn’t matter if you have the finest professional equipment and the most talented musicians; without suitable acoustics in the room sounds will not be accurately reproduced, making mixing much harder and not delivering the quality of sound you need.

As with many topics around music production, the use of acoustic treatment can quickly become technical and alienating for beginners or those looking to construct a small studio.

By bringing some simplicity and clarity to the topic, this guide aims to build an understanding of how to implement acoustic treatment in any recording environment, and in doing so, improve the overall sound produced in your studio.

What is acoustic treatment?

While they might seem similar, soundproofing and acoustic treatment have very different roles to play in the studio. Soundproofing requires dense materials that are often built into the walls to prevent sound leaking in or out of the space. While this will help to reduce unwanted external noise, it will not help to optimize the sound created inside the studio.

Acoustic treatment is used to control the acoustic qualities of a given space, minimizing the effect of unwanted echo and reverb to improve the clarity and quality of the sound produced. This is done using panels placed strategically on the walls and in the corners of the room to absorb or diffuse unwanted sound reflections, making for a cleaner final product. The increased accuracy of the stereo reproduction acoustic treatment provides will also allow for more accurate mixing due to the clarity of the sound.

With careful consideration, the use of acoustic treatment can also be relatively inexpensive, as panels can even be constructed as a DIY project.

Why is it needed?

As well as the shape of the room, every surface will impact on the movement of soundwaves. It is likely that most spaces will result in some degree of reverberation, echo and flutter issues.

Reflection is another major issue. While the majority of soundwaves will reach the listener directly from the sound source, a large percentage will only reach the listener after reflecting against walls and other surfaces. The resulting echoes can make mixing challenging, and do not effectively represent the sounds being recorded. Acoustic foam reduces the level of echo in a room by minimizing the effect of early reflections.

Installing specialist acoustic foam softens surface area to increase the level of sound absorption and reduce noise pollution. It also controls and minimizes the reverberations hard surfaces create, resulting in an overall better quality of sound.

With effective acoustic treatment, the quality of recording will not only be enhanced, but can be controlled and managed for different types of performance.

The Room

For most people, the space available for recording is going to be limited and will have its own natural faults. Every room will offer different benefits and problems. This may be down to many factors including the ceiling height, number of windows or the type of flooring. While the size and shape of the room cannot be changed, reducing the number of reflective surfaces will help to preserve your sound.

In the live environment, a reverberation time of between 1.5 and 2.5 seconds will ensure a full sound and clarity of speech. In a home studio setting, playback would require 0.5 seconds to achieve equivalent clarity.

The position of your workstation can also have a significant impact. To allow your monitors the space to accurately reproduce sound, they should be positioned a distance away from the walls, and to ensure an accurate stereo image, they should form an equilateral triangle between both speakers and the listening position.

Types of acoustic treatment

Acoustic Foam Panels: The main function of acoustic foam panels is absorption. This type of acoustic treatment is used in almost all studios, but is heavily used in home studios due to the cost and ease of installation. Acoustic foam is very high density and is often provided in panels of varying size and with a ridged or textured surface.

Depending on the room, a number of panels will be required. The most important locations to cover are adjacent to the speakers and on the walls directly in front and behind the listening position.

Each piece of acoustic foam paneling will provide additional benefit, so don’t be concerned if you can’t afford to fit a whole room at once. While a large number of panels may be required, covering more than 70% of the walls could have a negative impact by creating an overly deadened space.

Diffusion Panels: Often constructed from wooden panels, diffusion panels are a very effective but often expensive treatment for mixing rooms. By deflecting sound in a number of different directions, diffuser panels can reduce the influence of reflection and delay that could undermine an otherwise strong performance. Diffusion panels are ideal for bringing out the potential of smaller rooms and improving the sound quality in larger rooms when placed above the listening position.

Some of the most famous diffuser panels in the world are installed at the Royal Albert Hall. The ‘Mushrooms’ were first installed in the 1960s and are currently positioned directly above the stage and covering the mid-point of the ceiling, reducing the impact the high ceiling had on acoustics.

Bass Traps: Some of the worst problems in a room can come from the low-end frequencies. This is especially true in small spaces. For this reason, bass traps are designed to treat the corners of your studio space.

Porous absorbers are the most common form of bass trap. Constructed from heavy-duty foam, fiberglass, or Rockwool. This type of trap will tackle a range of issues including standing waves and flutter. They are effective across a wide spectrum but will need to be extra thick or fitted slightly away from the wall to deal with the lowest frequencies.

A more expensive option are resonant (or pressure) absorbers. These work best when positioned against a wall, saving space compared to some porous absorbers, however they are not common outside of professional studios due to the cost.

The most common resonant absorbers use either an airtight cavity (Helmholtz resonators) or counteract sound waves with a vibrating panel or membrane (diaphragmatic absorbers).

While budget may limit your quest for professional standards of acoustic treatment, optimum speaker positioning and an awareness of the ideal location to fit acoustic foam will help to make improvements to your sound as cost-effective as possible.

For more information, be sure to check out “How to Build Your Own Home Studio.”

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