Acoustical Treatments & Soundproofing two totally different issues!

Acoustically Treatments control the sound within the room so that you can hear the intended sounds within that room whether it is the human voice or a music or a movie soundtrack, without hearing reflected sounds, distortion and echoes of past sounds that have already occurred.

The acoustical treating of a room will insure that everyone clearly hears every nuance of the soundtrack. Think of it visually--and how unpleasant it is to watch a picture that is totally out of focus or images were pulsating. It is the same for the sound, when there is a blur of repeat and distorted sounds overwhelming what was intended, one cannot hear clearly.

When used in a Home Theater acoustical treatments adjust for room acoustics. The object of internal acoustical treatments is to let the ears hear sound directly from the speakers without interference from reflected, distorted remnants of the sound bouncing off the walls.

In this age of computers, our professional consultant will feed the dimensions of the room and speaker and furniture positions into a program. The program will then tell us where the panels should go and whether the panels or parts of the panels need to be reflective, defused and, of course, where sound needs to be totally absorbed.

Acoustical treatments are not only for home theater rooms. If placed strategically within the home, they will reduce much of the echo and noise caused by sound bouncing throughout an open floor plan making it a much more enjoyable environment.

Acoustical treatments come in hundreds of colors and fabrics and one of our suppliers can even cast high definition images or photographs onto special acoustic fabric to fit any décor.

Soundproofing, is keeping the sound from getting out of the room to areas not intended. There are many proven ways to keep much or all of the sound from getting out of the room. The success is always based upon materials, "construction" and budget.

Sound Abatement Techniques
4 Elements of Sound Proofing

How exactly do you build a soundproof room? Start with a basic understanding soundproofing construction. If you understand the basics, you'll have a more educated eye to view your problem room. In general, we are trying to stop vibrations from getting to "your" side of the wall or ceiling.

Below is an illustration of the typical noise problem through a typical wall. He's making noise on his side of this wall, and you hear it.

The red arrows in the above diagram demonstrate how sound is conducted from his side to your side. Rigid drywall is rigidly connected to the wall studs, which are rigidly connected to your drywall. The vibration conducts straight through.

The blue waves, indicate airborne transmission. His drywall is vibrating back and forth which produces a sound wave in the air cavity. This in turn vibrates your drywall and recreates the sound on your side. The drywall becomes a giant diaphragm and acts exactly like your stereo speaker moving back and forth re-creating recorded sound from your favorite CD.

Let's briefly look at the 4 basic elements of a well isolated room.

1. Decoupling

The first element is decoupling. Keep in mind that sound is nothing more than a vibration. The vibration will travel (conduct) easily if there is a nice solid direct pathway to follow, like the string between two orange juice cans. If we cut the string, however, we "decouple" the pathway, and the sound vibration stops (no conduction).

Obviously for soundproofing, we want less sound vibration to travel from one side of the wall to the other. It is therefore enormously beneficial if we decouple the framing in our walls (and ceilings). It's simple, inexpensive and highly effective. Let's look at different methods of decoupling:


You can see that all of these methods offer varying degrees of separation of the drywall on one side from the drywall on the other side. Again, all of the walls shown are superior to a single stud (common) wall.


We can see how decoupling the wall studs limits the vibration trying to conduct through the wall. We are left with the airborne transmission represented by the blue waves. Note how decoupling does not affect airborne transmission.

So our decoupled framing reduces a good deal of vibration, but not all. We need to continue to the other elements to reduce more.

2. Absorption

Air cavities will resonate. Ever "heard the ocean" in a seashell? Ever blow across the top of a bottle and heard the sound? Both sounds are actually the trapped air resonating. A hollow wall will also trap air that will resonate. When the wall is vibrated by sound (from your neighbor), the air in the wall cavity is also vibrated, just like a drum. This air cavity is another means for sound vibration to travel from one side of the wall to the other.

As you can see, even though the wall framing is decoupled, the vibrating air cavity will still transmit some sound through the wall between the wall studs. Simple fiberglass insulation will absorb some of this (absorption).

Insulation helps, and should be done if possible, but the vibration reduction is smaller than the other 3 Elements. You can use other insulation materials as well like cellulose, mineral wool and recycled cotton. The key is to keep the density low. Don't compress or pack the insulation.

So now we have a de-coupled and insulated wall framing. These elements stops much vibration, but not all. What do we do now?

3. Add Mass

A very important element. In this case we simply mean make the walls as heavy as you can. Common cost effective choices for heavy materials include Drywall, Plywood, OSB, and Cement Board.

For sound to conduct through a wall, it has to actually move the wall ever so slightly . A heavy wall is harder to move than a lighter wall. Simple as that. Drywall is one of the lowest cost sources of mass available. Best to use two layers of 5/8" drywall. It is very important to note that a heavy wall will still vibrate, just not as easily.

Note that adding mass improved things. It's harder for sound to move this heavier wall. You will still hear low frequencies (bass) quite easily.

This graph illustrates the performance gains from adding additional drywall. While adding mass obviously helps, it doesn't help as much as we need.

So we have a wall that is decoupled, has some insulation, and is heavy. Stops much vibration but still not all. Is there anything else we can do to reduce vibration?

4. Damping

The last element for soundproofing. If we could reduce the drywall from vibrating in the first place, it would make the jobs of the mass, the insulation and the decoupling easier and much more effective. After all standard drywall is a HUGE surface area that is vibrating.

Note how damping the drywall on the sound producing side of the wall reduced all vibration immediately. Again, the decoupling, absorption and mass all have less of a job to do, resulting in significantly improved performance.