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What do Acoustic Panels do?

Acoustic panels are not used for soundproofing. They are used to improve sound quality inside a room, theater, church, office, and many other buildings. Here are more details about acoustic panels, including types and styles and what you should expect from them. 


Simple Diffuser with Bass Trapping Absorbent Foam Acoustic Panels

How do Acoustic Panels Work to Improve Sound?

Sound waves travel very fast–about 1125 feet per second. Meaning that your room is filled with sound almost instantly. And a sound wave will bounce back and forth between 2 flat walls about 60 times per second. All those sound waves bouncing off flat walls, ceilings, and floors are repeatedly colliding with each other and reaching your ears at different times creating interference patterns that distort the sound you hear.

Each time a sound wave is reflected, it gets a little bit weaker, making the sound you hear even more confusing to your ears.

Absorbent acoustic panels eliminate about 70% of the sound by turning it into heat which dissipates out of the panel. These are small amounts of heat that do not constitute a fire hazard. By eliminating 70% of the sound on first contact stops some of it from coming back, helping the wave to decay quicker.

Bass traps work in the same manner. Absorbing bass frequencies and dissipating them as small amounts of heat.

Diffusion panels randomly scatter any sound waves that come in contact with them back into the room, breaking up any echoes or standing waves.


Placing Acoustic Panels for the Best Result

For best results hang your wall panels centered between floor and ceiling. Panels measuring 2′ x 4′ for instance, should be hung as 2′ wide and 4′ high–2′ off the floor and 2′ from an 8′ ceiling. Do not place panels directly across the room from each other. Place the panels across from a flat section of wall, window, door, picture, or anything else not an acoustic panel.

Any studio or home theater should have acoustic panels behind the speakers and on the opposite wall behind the audience. (Again, not directly across from each other.)


Acoustics on the Ceiling

You should have acoustic panels on the ceiling also. Usually above speakers or microphone. They do not have to be spread out across the complete ceiling–just a few inches apart. Stick to absorbent panels for the ceiling. They are usually lighter than diffusers and diffusers do a better job on the walls.

As with most everything on the ceiling, getting them up there and level is most of the fun. Eye hooks and wire or eye-hooks and zip ties will make the job easier. Consider Tonnen 2 pack Acoustic Panels. They are 2′ thick fiberglass with a solid aluminum frame making hanging easier. Using foam panels can be done but they have to be glued to a solid substrate to hang properly.


Acoustics on the Floor

Laminate or hardwood floors look great and add a warm feeling to a room. Unfortunately, they also provide another hard surface for sound waves to bounce off of and create noise clutter in the room. And you really can’t put down absorbing foam panels or diffusers on the floor.

Put down carpet or area rug to break up the reflections. As with acoustic panels on the walls, you only have to cover about 30% of the area to eliminate most sound wave bounce. If you want more absorption, consider installing RugPadUSA under any carpet or area rug you put down. For more on underlays please see our article Best Soundproof Underlayment

Note: Make sure you have Double Sided Carpet Tape when putting rugs on laminate.

Although technically not acoustic panels, furniture also works well to absorb or scatter sound waves that hit the floor. Soft furniture like chesterfields and upholstered chairs will absorb sound waves. Hard furniture like coffee tables and hard chairs work as diffusers and scatter sound waves around the room.

Types of Acoustic Panels

There are two types of acoustic panels–absorber panels and diffuser panels. To get the best out of your sound system or home theater, you will need a combination of both. Covering only about 30% of the wall and ceiling area is usually sufficient to make vast sound improvements to your home theater.

For more information on whole room sound treatment please see our article How to Sound Treat a Room.

For an idea of how many acoustic panels you will need, you can use the calculator at <acousticdesignworks.com> Your average 150 square foot room should have two diffuser panels with the balance being absorption panels. Plus bass traps.


Absorber Acoustic Panels

Absorber acoustic panels absorb some of the sound waves as they hit the panel–by design. The purpose of foam acoustic panels is to reduce, but not eliminate resonance in a room. Foam panels control residual sound by absorbing sound waves and dissipating them by turning them into heat.

Some manufacturers aim for 100% absorption and elimination of sound waves. Fortunately they are usually not successful. Otherwise your theater or studio could have a dead sound to it.

For more information on absorber acoustic panels, please see our articles:


Bass Traps

Bass traps are also absorber acoustic panels–thicker and heavier. Base frequencies are the most difficult to deal with. They also tend to gather in the corners of a room. Installing bass traps in each of the 8 three-way corners of a room will help reduce those hard to deal with sounds.

Some ‘Complete Room’ acoustic treatment packages have taller and wider corner panels to absorb base frequencies. They are generally 12″ – 24″ wide and can range in height from 36″ – 96″. They fit across room corners leaving a cavity behind them.

For more information on bass sounds please see our articles:


Diffuser Acoustic Panels

Diffuser acoustic panels break up the sound waves that come in contact with them–preventing the waves from reflecting back into the room undisturbed and hitting new sound waves. Diffusers do not absorb sound, but scatter the waves around the room. This means that the listener does not hear a clear echo.

Wood diffusers are among the best because the sound waves will be scattered by a hard surface in many random directions. Wooden diffusers are made up of a series of wells with dividers between them. The wells are different depths and manufactured to a mathematic formula to perform properly. (Although they may look like scrap wood thrown together, there is a method.)

For more information on diffuser acoustic panel, please see our articles:


End Notes

If you are not sure how much or how little acoustic treatment you want, or need, give some thought to purchasing an acoustic room kit like the Prime Acoustic London 12 Kit. It comes with 6 lb. per cubic foot fiberglass, fabric wrapped panels of various sizes and shapes–22 in all. Enough to do approximately 150 square foot room c/w instructions and hangars. These panels offer almost 5 times more absorption than typical 2″ foam panels.

The Prime Acoustic panels are excellent at addressing problems such as primary reflections, flutter echoes, standing waves, and excessive bass.

On the other hand, you may not want to plunk down a bunch of money until you are certain of a positive result. Absorbent 2″ thick acoustic panels are not very expensive. (You can pick up packages of 12″ x 12″ panels for less than $2.00 each.) You can put them up in your theater with stick pins to get an idea of how they can affect the sound. Once you are satisfied that you are on the right track, you can spend more money to get even better sound.


Terry Schutz

I have worked as a contractor, sales person, and business owner in the construction industry for over three decades--mostly in home renovations and also as a home builder. I have been married to the same wife for 46 years. We have 3 children and 4 granddaughters. I have also been writing semi-professionally for about 20 years--construction articles, personal stories, and politically incorrect social commentary.

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