How can I make my listening space sound better?
Written by Matthew Potter on January 30, 2018
Many people misunderstand what those fancy foam tiles in studio photos are doing, and don’t realize how much sound treatment could benefit them. Typically, it’s the audiophile who actually installs sound treatment panels… The guy with a fancy cinema setup in his basement or the musician with a studio/practice space. With the widespread popularity and availability of, not only powerful surround sound systems, but also home audio production, more and more people are buying and even building very effective acoustic diffusers and absorbers.
The big feature of surround sound systems is the isolated sound that goes to each speaker. As a helicopter flies off the screen to your left, you might hear it circle around behind you as the sound moves from one of the rear speakers to the other before the helicopter reappears on the right. But, if the sound from the speaker on one side is reflected back to your other ear by an untreated, sound-reflective wall, then it can lessen the illusion and experience. This is the reason a vocal booth or recording room will often have sound treatment all over the place. The sound should pass one time across the microphone and not come back. There are exceptions, of course, since for acoustic performances like piano, guitar, or choir the resonance of the room can make quite a difference. One would want to treat a room for those applications very carefully. But, in a basement EDM studio, treated walls will mean that the reference sound you are listening to is not colored by the added resonance of the space for a much more accurate reproduction of the source material. You may even find that you can turn your music up louder because you aren’t being bombarded by all the reflected high frequencies, cluttering it up.
Diffuser panels don’t absorb sound and they aren’t made of foam. In fact, they are often made of wood. They use a method of scattering the sound instead of absorbing it. As each sound wave travels through the air, it is a cohesive, defined wave moving through the air. If that wave hits a flat, hard surface, then it will be reflected cleanly and will maintain its structure. But, if the sound wave hits a multi-level surface and the different surface levels reflect the sound wave back at minutely different times, then the sound no longer forms a cohesive wave and the sound scatters and dies. This is actually one principle at work in the ridged foam panels we will discuss later. A popular design is to use 2″x2″ wooden blocks cut at a variety of lengths, and then assembled into a frame. But, there are lots of designs out there from long rectangular panels side-by-side at different depths, to decorative panels with a stone look. Not only are diffuser panels very effective at dealing with high to mid-range frequencies, they also can make an impressive design feature for a room.
Broadband Absorber panels
Broadband absorber panels are panels which, you guessed it, absorb the sound so that it doesn’t bounce back. Commercial products are often made from foam at a specific density. But, homemade versions are often made with fiberglass or rock wool (mineral wool). there are lots of DIY projects out there, but pay attention when they discuss material thickness and wall offset. Thick panels will absorb low frequencies, and thinner panels will absorb higher frequencies. But, an important factor is the offset from the wall, since you would ideally mount these panels with a specific gap between the panel and the wall. For a thick, wall-mounted bass trap, you might be surprised at the size of the ideal gap to place the absorber in the “sweet spot” to catch the sound wave as it comes back off the wall. For this reason, many high-end and commercial installations actually build recessed bass traps into the wall. These sound absorbers are probably the most cost-effective to build at home. And, when covered in fabric, can make a dramatic decorative statement on a budget.
Acoustic Foam tiles
Everyone knows the classic image of a vocal booth, the “egg crate” foam or ridged foam panels on the wall in alternating directions… The benefit of using this kind of foam is that you get to scatter the reflecting high frequencies as well as absorb some of the mid frequencies. Foam like this can be very inexpensive (especially online). But, if you have 2″ thick foam panels, don’t think you will be absorbing bass. They are much too thin for that. But, as long as you know what to expect from it, acoustic foam does a great job (and it has a cool, pro look to it, too). But, don’t use egg cartons. They really don’t work the same.
Corner Bass Traps
When dealing with heavy bass from a subwoofer, the sound is far less directional and prefers to just go “out”. It fills the room and seems to gather in the corners. This can cause the corners of the room to really sing with too much bass and drown out other sound. By filling those corners with foam (or even fiberglass) bass traps, you can absorb the bass where it gathers and gets muddy. This can really keep the sound crisp and clean at full volume. This is another easy, relatively inexpensive DIY project with lots walkthroughs available online.
Whether you are turning your mancave into the ultimate home theater or simply improving the usability of a large, resonant room, there are lots of options for every budget. You might surprise yourself with just how good you can make that room sound. And, with how quickly it becomes the favorite spot for your friends to hang out!