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Acoustic Panel Sizing Guide – How Big Should They Be?

In Acoustic Panels, Buyer's Guides by Jonah MatthesLeave a Comment

If you’ve made the commitment to get the most out of your speaker system, then you know you’re going to need acoustic panels. But figuring out all the details can be intimidating. You might be considering making your own panels, or buying them ready-made, but what about the size of the panels themselves?

Although the size and shape of a room can have a big impact on the effectiveness of acoustic panels, a good rule of thumb is to target covering around 20% of the wall’s surface area with panels that are 2ft by 4ft, and at least 2in thick.

There’s a lot to unpack there. How do you know what 20% of your wall’s surface area even is? And can you get away with panels that are thinner than 2in? We’ll discuss all these details below, but first, let’s talk about the size of the panels, and then we’ll cover how you should distribute them based on the details of your room.

Common Sizes for Acoustic Panels

Acoustic Panel Sizing - Smaller

As far as acoustic panel sizing is concerned, there are a few details you need to be aware of. There are some loose standards around the height and width of panels, though you can build custom panels or, indeed, special order them in any size. Then, there’s the thickness to think about.

Height/Width

The standard height/width of acoustic panels varies across the market. There are plenty of 2ft-by-4ft panels like the ATS Acoustic Panel (on Amazon) that are designed to get you a really good bang for your buck when it comes to wall coverage.

But there are plenty of smaller options on the market as well, like the DEKIRU Acoustic Foam Panels (also on Amazon) that comes in packs of 1-foot-square panels. These are nice because you have a little more flexibility in deploying your sound absorption if there are lots of speakers in the space. 

You’ll most likely want to get 2x4ft panels to cover the most surface area you can, with a few smaller panels scattered around to match irregularly shaped walls. Or, if you end up building your own panels, you can obviously set whatever size is right for you.

Thickness

The thickness you need is based on the type of sound you need to treat your room for. Deeper wavelength sounds require thicker panels, but that’s not the whole story: placement matters too. Bass traps are typically put in the corner, but panels are mounted on the walls and/or ceiling.

The wall panels are typically there to address higher frequency sounds, like the dialogue in a movie, or music with lots of female vocals and a higher frequency sound in general. These panels are typically 2in deep, and that’s enough to get the job done.

But if you have a really nice sound system with one, or even more than one subwoofer, you’ll definitely need thicker panels to capture those longer wavelength sounds.

Bass traps can be much thicker, well over 2in. At their deepest point (they’re usually triangular in shape) it’s not strange for bass traps to be over a foot deep. And the placement: bass traps usually end up in corners, which match their wedge shape.

Things to Consider When Sizing Acoustic Panels

When sizing acoustic panels, there are a few things you need to consider. Below there are details about how the size and shape of your room, and how the purpose of your home theater setup can influence your decision. Ultimately, the amount of wall space available will drive some of your decisions here, especially about how large the panels ultimately need to be.

Room Size and Shape

Large Acoustic Panels in a Home Theater Room 1 - Smaller

The size and shape of the room have a big effect on the effectiveness of your acoustic panels. Not only can irregularly sized rooms complicate placement, but sloped ceilings, and/or light fixtures can be interesting to workaround if you’re putting in ceiling panels. You may also have furniture or artwork on the walls that limit where you can put acoustic panels.

For a “normal” square or rectangular room, the placement of acoustic panels is very straightforward. You’ll want some in the front, back, and on the sides, pretty much wherever you can put them. Even coverage on every wall should be your goal, with at least three panels on all the walls except for the one with the screen. And if you have a subwoofer, put a bass trap in one of the corners.

For much longer rooms, or a room with high ceilings or an open concept, things get a little messier. There will be some obvious surfaces opposite the speakers that need to be covered, but there will also be areas that you can’t really address. In cases like this, you’ll need to do what you can by addressing the space, maybe with ceiling panels.

The way you should think about this, though, is that wherever there are flat surfaces in the room, the sound will bounce off of it, and you don’t want that to happen. So even if the room is shaped in a way that you can’t get a panel right across from the speaker, it will still help to just start putting panels on flat surfaces. 

Do the best you can by putting panels in the “right” spots, across from speakers, then put a few more up, and add even more if you’re still not happy with the sound.

Purpose of the Room

The purpose of the room should play into the logic behind your acoustic panels a lot. If you’re primarily thinking of managing the sound in the room to get the most out of your home theater system, then you need at least a couple panels across from all of your speakers.

But unless you’re going for the full theater experience, that’s probably where you can stop. Add a bass trap and call it a day.

Now, if you’re really going to emulate the full effect of a home theater, to the point that you have multiple subwoofers and a speaker system that is running Dolby Atmos sound, it’s probably going to be worth your money to add a few more acoustic panels.

Specifically, another bass trap and even ceiling panels should be on your mind. And if you’re worried about lights, don’t worry–you can cut ceiling acoustic panels to match your lights without reducing their effectiveness much.

However, if you’re in a studio space, or trying to acoustically treat a room to the point that you can do high-quality sound recordings or music production, then you’re in the next tier: you need sound absorption all over the place. This isn’t the 20% coverage that we mentioned as a rule of thumb for home theaters, it’s as near to 100% as you can get.

As you can see, the scale of how much acoustic treatment you need begins to slide up quickly based on the purpose of the room. Think of it in terms of the percent of your wall that’s covered: you could even choose to start at 10% and see if that is good enough for you, adding more panels as needed. But the purpose of the room should be considered when you’re deciding where to start.

Available Wall Space

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Lastly, the amount of wall space available will heavily limit the amount of panels you can hang. This is good in a way: less wall means less surface for sound to bounce off of.

But if you can’t use a panel because you have a picture on the wall, that’s bad news. The picture is still a flat surface that will reflect sound, and it’s limiting your ability to acoustically treat the room in the right spots.

So, you should consider how much of your wall is available, and how much you’d like to give up to acoustic panels because you can’t mount anything on top of them.

The one other option here is that you can squeeze more acoustic treatment into the space by mounting acoustic panels on the ceiling, but these serve a somewhat different purpose: they’re not directly across from any speakers, so they’re not going to give you as much bang for your buck when it comes to sound absorption.

If you lack wall space because of furniture and decorations that are blocking where you can put panels, that’s just the way it’s going to be. You can likely still fit a bass trap somewhere, but short of moving speakers so that they’re aimed at “open” spaces of wall, you’re not going to be able to get much more sound quality out of the space.

Do Larger Acoustic Panels Absorb More Sound?

Large Acoustic Panels in a Home Theater Room 2 - Very Smaller

Larger acoustic panels will absolutely absorb more sound. The way an acoustic panel works is to trap sound within it, absorbing it by allowing the sound waves in, but never letting them out. So it stands to reason that the deeper a panel is, the more sound-absorbing material you have, and the better it will trap sound within because it has more room to get trapped in.

But it’s not just thickness that affects this, the overall size or surface area of the panel has an effect as well. A 1ft by 4ft panel that’s 1in thick will absorb less sound than a 1ft by 4ft panel that’s 2in thick, but a 2ft by 4ft panel that’s 2in thick will be better than both of them.

So how do you know? Since you can always add more surface area of panels (by adding more panels in the room), we recommend starting out with panels that are at least 2in thick. If you start too slim, you may end up having to replace those panels with thicker ones. But if you start with a decent thickness, you should always be able to “scale up” by adding more panels, not replacing the ones you already have.

What Now?

Maybe now you understand a little more about what goes into the question of how big your acoustic panels should be. There’s a surface area to target–at least 20%–but there’s also a thickness that you need to think about. 

And the unique configuration of your room may give you some limitations, but if you consider the purpose of your room and the goals you have for it, figuring out where you should start with acoustic panels should be a breeze.

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