If you’re on your way toward the perfect home theater, there’s no shortage of new niche technologies to get comfortable with. But after all that advanced audio and video management equipment, one thing you may be wondering if you also need acoustic panels. You may have already seen our article on just how important acoustic panels are, but do you know how they work?
Acoustic panels are surfaces made of shaped foam and/or fabric covering which improve sound quality by absorbing sound waves, preventing them from bouncing around a room and interfering and reducing the quality of other sound waves.
If that sounds a little strange, that’s because it is. After all, it’s hard to picture actual sound waves moving around your space, and how much of them can really bounce off of a wall? Would you really notice a difference? To understand if you need acoustic panels for your setup, let’s look at how they work, and if they can really get you any results.
Acoustic Panels Explained
Acoustic panels work by trapping sound waves within the foam materials they’re made of. Since all sound is vibrations in the air, sound waves act as a sort of cave that the sound waves can travel into, but not out of. For aesthetic purposes, there is usually a fabric covering for acoustic panels meant to be in open spaces.
You’ve probably seen acoustic panels before, on movies or youtube videos, in the background of sound stages or production studios. Sometimes you can see exposed surfaces that look jagged or saw-toothed. That Triangular shaping forms a funnel to sound waves, which bounce back and forth until they’ve spent all their energy.
Some panels don’t have any “teeth” cut into the face, instead relying on the absorbing properties of the foam itself to do the work. If the panel wasn’t there, sound waves hitting a given space would bounce right off the wall, then the next wall, then the ceiling, etc., which is how you can get into a problem with too many sound waves bouncing around your space.
And since different sound waves have different wavelengths, there are actually different types of acoustic panels. But don’t worry, there are really only two main categories: “normal” wall panels used to address mid and high-frequency sounds, and “Bass Traps” that are designed to go in corners and have a bit deeper design.
Components of Acoustic Panels
From the description above, you can probably already picture the main components of an acoustic panel: the foam absorbing material and the fabric covering.
The foam can actually be a few different types of material, but they are all variations on the same theme: the foam’s job is to be just porous enough that sound can get inside of it, but dense enough that the sound bounces around and “gets lost” inside. Materials like compressed wool can be a good replacement for the foam because the properties of wool allow it to get the job done.
Next, there’s the fabric covering of the panel, which hides the foam and allows the panel to be more aesthetically pleasing. There’s a wide variety of materials that can be used as the fabric covering, so long as it’s porous enough to allow sound in. Heavy, thick coverings aren’t used because they’d bounce the sound off, defeating the purpose.
Do Acoustic Panels Really Work?
So, it’s clear acoustic panels are designed to achieve this goal, but is this all just theory, or is there really something there that can enhance your space? The good news is that you can get very real results from using acoustic panels, but they’re a tool designed for a specific problem.
When are Acoustic Panels Effective?
If you’ve got a nice surround sound system, or maybe a high-end soundbar that has 3.1 or 5.2 channels of sound, you’ve now got enough channels that sound waves bouncing around the space can cause a problem.
Every speaker you have is putting out sound in one general direction (with the exception of subwoofers which fire a bit differently). And if you look at your walls, there’s probably not a lot there except flat surfaces. Even when pictures or furniture block the well directly across from the speakers, it’s usually a lot of flat, hard surfaces that bounce the sound right off.
So if you’re pumping a bunch of sound into the space, it has nowhere to go other than to bounce around over and over and over again. This wouldn’t be a big problem, except when the volume goes up, and the number of speakers in the room go up, it starts to overwhelm the space with sound.
Then you have a real problem: if you’re trying to get high-quality sound, maybe from a Dolby Atmos source, then all of those sound waves will be crashing around, not just into walls but into each other. So those high-quality sound waves that leave your speakers don’t even have time to make it to your ears before they’ve been crashed into by dozens of other waves that were already bouncing around.
Are They Actually Effective?
The good news is that this problem really can be solved with acoustic panels. To stop the sound waves from crashing around, something has to absorb them, and the foam in the acoustic panels does this very well. But to be effective, the panels have to be placed in the correct spots.
This may sound like a problem at first–after all, it’d be a lot simpler to just paper the walls with acoustic panels and forget about it. But unless you have a bottomless budget, you’ll want to have the minimum number of panels in the right spots.
And if you’re comfortable with thinking about the sound in the room as sound waves, this is actually a pretty straight forward problem to solve. First: you want the speakers facing you, wherever you’ll be using your home theater system. Next, you want the acoustic panels to be in line with the speakers as much as possible so that the waves that pass by you are then absorbed.
This means front-firing speakers from a nice soundbar should have panels across from them in the back of the room, and rear-facing speakers aimed diagonally at the couch (for instance) should have panels to the left and right side of the screen, where those sound waves should terminate.
If you get the placement down, there’s no question that acoustic panels work to solve the problem handily, so long as the quality of the panel itself is there too.
What About the Ceiling?
You may notice that one large, flat surface of your room was omitted from the discussion above. Your ceiling, like the walls, will be just as bad about reflecting sound waves, and it may even be worse since your ceiling is likely a lot more exposed than your walls, which may be blocked by furniture.
The “scalpal” approach of putting acoustic panels on the walls directly across from your speakers is a great place to start, but you’ll continue to get even more impressive sound out of your speakers by taking a “sledgehammer” approach: mount acoustic panels basically all over, with at least three panels above, behind, and in front of where you’re sitting, as well as on the ceiling.
I know, I know–especially if you’ve already mounted a projector you were probably hoping to never have to touch anything in the ceiling again. And what about light fixtures?
There’s a lot to figure out here, for sure, but that’s why you come to a blog like this one. If you’ve got canned lighting, then you can simply measure out where you’ll put the acoustic panels and then cut a hole in them. That’s one problem solved.
But what about mounting the panels to the ceiling itself? You’re right if your first instinct is that that may not work. What you want to do is drill into the joists on the other side of your ceiling with screw eyelets, and then do the same on the back of the panel.
Then, you can attach the eyelets with zip-ties. This will allow you to leave a one-inch gap between the panel and the ceiling, which will increase their performance.
Should You Buy Acoustic Panels or Build Your Own?
If you see the benefit of acoustic panels improving your sound quality and reducing the amount of “sound leakage” from your home theater, then you’re ready to move forward. But at first glance, the number of panels required and the relatively steep price may make you wonder if you should be buying panels or building your own.
With any DIY projects, you risk ending up spending more time and resources than you ever would have with the store-bought options, but luckily acoustic panels are simple enough to assemble that you can make them yourself pretty easily. In fact, we even have guides on the best insulation materials (LINK) and the best fabrics (LINK) you should be using.
But, nothing beats the simplicity of simply buying the right product, saving time and effort. So, if you want your acoustic panels now, and you’re not too worried about the cost, then buying something like the Acoustimac DMD Stagger Design Pack (on Amazon) or some ADW Acoustic Panels (also on Amazon) may be a better option for you.