ACOUSTICS: AN ESSENTIAL CONSIDERATION

Are you mulling over the idea of adding a home theater or a listening room to your home? There are many things to consider in the design of such a room, but acoustics must be at the top of the list in order to achieve the high-fidelity sound environment that you expect from your investment dollars. With this issue properly addressed, sound waves flowing through the space in the room deliver awesome audibility.

Properly installed acoustic treatments mitigate “noises” in the room that most people don’t recognize as a problem. These erroneous sounds are equivalent to the background noises in a busy restaurant that make it difficult for you to hear clearly what the person seated right next to you is saying. There are simply too many sounds bouncing off the solid surfaces in the room for your ears to differentiate only the sounds that you want to hear. However, unlike in a busy restaurant, when you sit down in your theater or listening room, there are usually a limited number of people present, who are making very little noise while enjoying music or a movie. Yet, without acoustical treatments in the room, you may still experience difficulties clearly understanding the speech of characters such as Sherlock Holmes in the TV show Elementary, or the colorful tonal variations in Beethoven’s Fifth Symphony. In addition, the bass (low frequency) sounds may be so amplified that you experience more nervous tension and irritation than therapeutic relaxation.

THE CULPRIT: NO SOUND MANAGEMENT

That irritating sound environment is actually caused by poorly managed sounds that you would prefer to hear with clarity and precision, of course. When your speakers emit sounds, those frequencies flow through the room and reverberate off of any hard surfaces that they strike. Like anything else that strikes a solid object, the collision causes vibrations. Those vibrations are reflected back into the space in the room, hence the reverberation, or echo effect.

High-frequency and mid-frequency sounds are usually the culprits causing the room to sound like an echo chamber rather than a relaxation chamber. Bass frequencies, on the other hand, love to congregate in the corners of a room, especially if the room is small. Conversely, in a large room, there may be dead spots where no bass frequencies can be heard at all. Either way, these particular frequencies are not being evenly distributed throughout the room.

THE FIX: EFFECTIVE ACOUSTICAL SOLUTIONS

So, how can these issues be resolved? Specifically, what kinds of acoustical treatments are available for each of these common problems:

• Echo/Reverberation

• Uneven sound distribution (dead spots and frequency puddling)

• Disruptive noise from outside the room

As previously mentioned, echo/reverberation issues are primarily caused by mid and high frequencies striking solid surfaces and then being reflected back into the room, where each frequency will likely strike another solid surface, causing the problem to repeat itself. The more solid surfaces in the room, the more times the signal will bounce around, causing multiple distortions. This situation is further exacerbated if the room is small and square, with a low ceiling. The sound is confined within such a limited area that it causes it to bounce around to a greater degree than in other room configurations.

Resolving this problem, then, starts with room dimensions. In an existing home, the only way to change the size, shape and ceiling height of the chosen room is to remodel it. That may very well be an undesirable option for you.

A BETTER WAY

Isn’t there a simpler, less disruptive way to deal with such an existing room? Yes, of course there is! Furnishing the room in an acoustically-friendly way is the first step. You can use:

• Soft furnishings, such as sofas and chairs covered in non-synthetic fabrics (believe it or not, synthetic fabrics have a sheen that can cause sound reflection)

• Soft throw pillows, and even blankets (non-synthetic)

• Soft, heavy window coverings (non-synthetic)

• Carpet and/or area rugs (non-synthetic)

• Fabric-covered room dividers (non-synthetic)

• Wall tapestries (non-synthetic)

• Specialized media consoles with built-in noise-dampening features

• Large house plants

These furnishings all serve to dampen vibrations and prevent reflections!

The next step in remediation of reverberation issues in a small room, and for that matter, any room, is to mount acoustical panels on the walls (and if needed, the ceilings) to absorb excess reflected sound. These foam panels are covered with non-synthetic fabric and can feature colors and designs to match the décor of the room, allowing them to “disappear into the room.” They can even resemble works of art.

In addition, a “star ceiling” constructed of acoustical tiles could be installed for added sound absorption and visual effects!

Further, if bass frequencies are pooling in the corners of a room, fabric-covered structures called bass traps can be installed in each corner to specifically absorb the excess sound.

Of course, in a much larger room, a major challenge can be the mitigation of dead spots where no bass frequencies can be heard. This issue involves the inability of those frequencies to flow long distances throughout the space in the room. It can be overcome by using a minimum of two subwoofers plus acoustical panels that disperse, rather than absorb sound. When strategically interspersed with the absorption panels, these diffusion panels effectively redistribute sound evenly throughout the room.

Along with all of these interventions, it’s important to remember that some reflection of frequencies is necessary in order to preserve the original sound dynamics. The room must be “tuned” to a precise balance of reflection, absorption, and dispersion.

NOISE FROM OUTSIDE THE ROOM

So, what about those annoying noises invading your space from outside the room, as well as the booms of your favorite action movie permeating rooms beside your theater? Unfortunately, this problem is not as easily overcome. But if the noise from a laundry room, bathroom, children’s playroom, or even outside street traffic is causing further disturbances in the acoustical characteristics of that special place where you go to relax, you will need to fix the problem. Your family and neighbors will appreciate it, too.

This solution is actually one that must be planned for before you decide to do only the simpler remediations previously discussed, because it entails ripping out all of the existing sheetrock in the room so that sound-proofing wool insulation can be installed. This heavier, denser insulation further enhances the acoustics of the room, killing reverberations and “hollow” sound, as well as keeping nuisance noises out of the room.

When the new sheetrock is installed, it should be ½ to ¾ inch thick. It is also very helpful to coat the studs with an adhesive, such as Liquid Nails, as the sheetrock is being installed. Doing so further dampens vibrations that could be caused by the sheetrock panels vibrating against the studs.

At AV Enthusiast, we understand that all of these needed interventions can seem overwhelming. But we are here to help! We provide the expertise to help you design your project for maximum acoustical integrity and are dealers for some of the best products in the industry, including acoustical treatments from Kinetics Noise Control and theater-friendly furnishings from Jaymar and BDI.

To schedule a consultation in your home, call us at 256.882.5081. Or drop by our Huntsville office at 514 Madison Street during normal office hours of Mon-Fri, 9-5 or Saturday 10-3.

We look forward to meeting with you!