Sound Absorption and Acoustical Panel FAQ's
Q: How many acoustic panels do I need in my room?
A: Our online room acoustics analysis is a great tool to find the right answer for any room. You provide some information about the room dimensions and surfaces, and our system crunches the numbers for you.
Q: Why are your prices so low?
A: We purposely set our prices lower than the competition to bring you the best value possible. We can do this and still run a profitable company because:
- We are the factory, selling nationwide through e-commerce. This eliminates markups at the distributor and retailer levels.
- We're located in smalltown Illinois where buildings and labor are available at a reasonable cost. We have no glamorous headquarters or expensive celebrity endorsements.
- We buy our materials in big quantities at the best possible prices.
- We work hard and always look for better ways to operate.
Bottom line our entire company is designed to bring you effective, attractive acoustic panels at a common-sense price.
Q: Where should I place the panels in the room?
A: In general, where you place the panels in the room is not critical. A visually pleasant appearance is often the guiding factor in placement. The most important thing is simply to get the total square footage of panels into the room somewhere. No matter where you place them, the panels will soak up the extra sound that is bouncing off every surface in the room.
That said, we do have a couple of non-critical guidelines for acoustic panel placement. First, you get more absorption per square foot of panel when the panel is placed in or near a corner. Said another way, you'll need slightly fewer panels in your room if you place some of them in or near corners.
Second, if there is a primary source of sound in the room, such as speakers at one place in the room, it's a good idea to place panels at first reflection points. These are places where the sound can come from the source, bounce once, and reach the listener. For example, on the side walls of a listening room midway between the listener and the speakers. This is because sound that reaches the listener after traveling an indirect path arrives just a little later than sound that came directly. This means your brain has to sort out multiple copies of the same sound, making things sound less clear and making speech more difficult to understand. Adding panels at the first reflection points reduces the late-arriving sound so your brain can focus on one clear copy of the sound.
Q: I need to keep sound from going through my apartment walls (or through a window, or from coming in from the street). Will your panels do that?
A: What you need is acoustic isolation (keeping sound from one area isolated from another area). Good isolation is tough to accomplish because our ears can hear even tiny amounts of sound that come through. We sell acoustic absorption panels which are primarily used for controlling echoes and reverb, not for isolation. If you added enough panels you might muffle the sound some, but the result would probably not be satisfactory.
My two pieces of advice on isolation are:
- Make it airtight.
Get rid of gaps under doors, etc. Even a small gap will let a lot of sound through. This makes a big difference and is usually more doable than #2. If you make it airtight you'll reduce mid and high frequency sounds, but still have muffled low frequency sounds coming through.
- Make it rigid and heavy.
Low frequency sound (bass) requires stiffness and mass to bounce it off so it doesn't come through. Concrete walls are great, but I realize you can't just pour one in your living room. Heavy plywood over a window, double-layer sheetrock on a wall, anything that adds stiffness and weight to your sound barrier will help keep those low frequencies out. And remember, airtight first, rigid and heavy second.
Q: Is the 2-inch or the 4-inch panel thickness best for me?
A: The answer depends on three things:
- Budget: The 2-inch panels cost a little less to buy and half as much to ship. The total difference is $6 to $12 per panel.
- Purpose: If you are concerned about bass absorption the 4-inch panels perform 4 times as well as the 2-inch panels at 125Hz. However, the two thicknesses perform equally well at 500Hz and above.
- Preference: Some people like the look of the thinner panels better on the wall, some don't. Some like to "go with the best" just to be on the safe side.
Both thicknesses work very well to reduce reverb, ringing, and unwanted reflections in your room. The 4-inch panels will do more to even out the bass in the room, but they are not true bass traps and they will not absorb much below 100Hz.
Q: Can I order custom size panels to fit my situation?
A: Yes, we can supply both our 2 inch and 4 inch thick panels in custom sizes. For a quick price quote just give us a call toll-free at 1-866-787-7881 and let us know the length and width you need.
Q: Do your panels release dust or fibers into the air?
A: We find that the fabric we use to cover the panels does a good job keeping any dust or fibers from escaping. We haven't had any trouble with that.
Q: How are the panels normally attached to the wall?
A: Our panels come with our professional installation kit containing special aluminum clips, anchors, and screw for neat and secure installation on drywall, wood, or concrete walls. Click here for full installation instructions. (PDF)
Q: How about mounting panels on a ceiling?
A: Sure, not a problem. Some customers will drill small pilot holes (from the back through to the front edge of the panel) and put screws through those holes and into the ceiling (preferably into a joist or other solid structure). The edge frame of the panel is solid and will support screws without a problem. Others will use screw eyes and/or screw hooks in the back of the panel and in the ceiling, sometimes with sections of wire to suspend the panels a couple of inches or more below the ceiling. The hooks and eyes can also be hooked together, or held together with small cable ties. The 24x48x2 inch panels weigh 10.5 pounds each, and the 24x24x2 inch panels weigh 5 pounds each, so there's not a lot of weight to support. If you are working with a drywall ceiling, be sure to use suitable drywall anchors anywhere you are screwing something to the drywall. Of course, whatever method you choose, use your common sense to make sure the panels are securely attached.
Q: Why do the panels have a solid wood back?
A: The 1/4" wood back provides strength for the panel, and makes it easy to hang the panels on the wall, or attach hardware such as hinges, hooks, or other hangers.
Acoustically, the solid back against the wall is about the same as the panel with no back against the wall. Either way the sound enters the front of the panel, is reflected by the back and/or wall, and exits through the front again.
Where the back can be undesirable is if you are trying to absorb bass and you want an air gap behind the panel. This air gap is to allow the sound to travel through the panel, some distance in the air gap, reflect from the wall, back through the air gap, and back through the panel. That distance is helpful in absorbing low frequencies (because they have long wavelengths). Most of our customers mount our panels against the wall for broadband absorption and control of reverb, and this works very well.
We have had the panels absorption tested (solid back and all) by Riverbank Acoustical Laboratories and they rate very highly. See the test results on our 4-inch panels for the absorption coefficients at various frequencies.
Our 4-inch panels are available with fabric-covered open backs. If you plan to install your panels across a corner or spaced away from the wall for an air gap, we recommend that you select the open back option when adding the panels to your shopping cart. This option is not available in 2-inch panel construction.
Q: How is mineral wool different than fiberglass absorption material?
A: There is very little difference. Mineral wool is made from basalt rock that is melted and spun into wool. Fiberglass wool is made from silicon rock (glass) that is melted and spun into wool. The mineral wool has a higher melting point, but that has no effect on the acoustical properties. Mineral wool and fiberglass of similar densities have nearly identical acoustical properties.
Q: What's the difference between rigid fiberglass board (like Owens Corning® 703) and Sound Attenuating Fire Batts (SAFB)?
A: There are no significant differences in acoustical properties (how they absorb sound). There are two significant differences in physical/mechanical properties.
1) Density. SAFB has a density (weight) of 2.5 pounds per cubic foot, which is the most cost-effective density for absorbing sound. Higher densities absorb sound only slightly better, so they are not worth the extra cost of material in most cases. 703 is the Owens Corning rigid fiberglass board product and is commonly used for sound absorption. It has a similar density at 3.0 pounds per cubic foot, and nearly identical acoustical properties to SAFB.
2) Rigidity. SAFB is a thick batt, like a heavier version of common household insulation batts. Rigid Fiberglass board is manufactured as a relatively rigid board that holds it's shape.
Q: How can I attach fabric to Owens Corning 703 or 705?
A: Here's a process that seems to work well:
- Apply spray adhesive such as 3M Super 77 or Ram-Tack High Tack Spray Adhesive to the fabric and to the surface of the fiberglass board.
- Use plenty of adhesive, spray a lot on and you'll get a better bond.
- Press the fabric onto the fiberglass board smoothly and allow to dry for at least an hour.
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