What Are Acoustic Panels and How Do They Work?

Acoustic panels are a solution to noises that distract from your listening pleasure, whether you’re talking on the phone, recording music or shooting a video. But, how they work exactly, and how to set them up optimally is not something you would know right off the bat. So, I put together this article through the research I have done to answer these key questions.

So, what are acoustic panels and how do they work? Acoustic panels are installed to improve the sound within a room. There are two types of acoustic panels, diffusers, and absorbers. Diffusers stop the sound from reflecting off walls and ceilings, whereas absorbers absorb the sound waves as they hit them.

Exactly where to place them needs a bit of explaining. As well as, more detail about what they are made from and how they work. So, read on to discover the answers to these and more tips related to acoustic panels.

Before moving on it is important to note that acoustic panels are also called sound absorption panels, soundproof panels, or sound panels.

Where Do You Place Acoustic Panels?

Before answering this question, you need to know a bit of sound theory to get the best sound quality for your room using acoustic panels. It is a common misconception that acoustic panels reduce outside noise from the environment. But, this is not the case. I will cover this topic in more detail towards the end of the article.

For now, I will explain how sound behaves in a room. So, that you can troubleshoot sound issues that come up yourself when installing acoustic panels. After that, I will explain step by step how to find the best place to put your acoustic sound panels to get exceptional sound quality in your room.

How Does Sound Behave in a Room?

Let’s talk about “Acoustics”, which is basically “how sound works in rooms”. It may seem complicated, so let’s make it simpler. Most rooms have flat walls and flat ceilings, and sound bounces off of these.

So How Does That Affect the Sound?

There are two types of sound: direct sound and reflected sound. Reflected sound arrives at our ears later than direct sound, even though it started out at the same time. Because it’s traveling farther. Also, a wall is only one flat surface -there are at least six in the average room-, and that’s a lot of reflected sound.

But Why is Reflected Sound Bad?

Reflected sound creates destructive Interference patterns that change the original sound wave. Here’s the problem: Original sound waves are distorted by strong later-arriving reflections.

Also, sound travels really fast, about 1130 feet per second (344 meters per second). A sound wave will bounce back and forth between these two walls about 60 times in one second. Sound travels so fast, it fills a room almost instantly. This is also only one bounce angle – every room has thousands.

How Can Acoustic Panels Be Used to Improve Sound Within a Room?

There are two acoustical tools – an absorber to reduce the strength of sound bounces. To a sound wave, an absorber looks a little like a hole in the wall. So, some of the energy doesn’t come back. 

An absorber works by reducing the strength of reflected sound that would otherwise cause more destructive interference. But, if we use only absorbers in a room, it makes it sound dull and unnatural. 

Historically, humans don’t like overly-absorbent rooms. So – let’s use the second of our two acoustical tools – the curved-surface diffuser. It also reduces the strength of sound bounces. 

A diffuser works by scattering the sound reflections in different directions, smoothing out destructive interferences throughout the room. Room acoustics are greatly improved using

a combination of absorption and diffusion. It’s all about reducing those flat-surface reflections.

Use a combination of absorbers and diffusers, and your room will sound a lot more natural. With that said, it brings us to the different types of acoustic panels.

What Are the Different Types of Acoustic Panels?

There are 2 primary types of acoustic panels. They are:

Ideally, when listening to sound you want to hear the sound directly. When the reflected sound makes its way into your ears, it mixes with the new unreflected sound which confuses your brain. 

This makes the sound quality not as good. It increases how much brainpower you have to use and can make you uncomfortable after a lot of listening.

The Different Shapes of Sound Absorber Acoustic Panels and How They Work

With sound absorber acoustic panels, the old adage comes up -form versus function-. The best performing acoustic panels stick out a lot and don’t blend in. But, they perform best in the sound muffling department.

Smooth	Smooth panels work somewhat. But, they aren’t the most effective. They are made from an absorbent foam that muffles the sound waves.
Wedge	A wedge is shaped like a triangle. The point of the triangle faces the center of the room. The base of the triangle sits flat against the wall. If a wedge panel is placed on a wall it can be installed either horizontally or vertically.  Wedge acoustic panels split the sound waves and absorb them. When wedge panels are placed side by side, then soundwaves are split and also bounce back and forward down into the corners. Expending their energy and deadening the sound.
Eggcrate	Eggcrate acoustic panels are shaped like an inside out pyramid. As the name suggests they look exactly like the cardboard packaging that eggs come in.  Once sound waves enter the panel they are trapped within them, reverberating and getting absorbed into the material at the same time.  These are used more in sound studios rather than home theatre systems. Where the quality of the sound is more of a priority than the way they look.
Pyramid	Pyramid-shaped acoustic sound panels effectively muffle the noise in a similar way to egg-shaped pyramids. Except they are the opposite.   The flat square side of the pyramid sits against the wall and they are interlocked. They function in the same way as the egg-shaped acoustic panels and wedge acoustic panels. When the sound waves hit the panel the waves are split in four ways by the pyramid. Then the soundwaves bounce around progressively getting absorbed and bounce around a lot in a short period of time dissipating their energy.  Predominantly used in sound studios, they don’t blend in with the decor. But, they provide exceptional sound muffling capabilities, giving you exceptional sound quality.
Spade	Spade acoustic foam has grooves that appear as parallel lines. They are installed with the grooves facing in different directions. They appear flatter and more uniform.  So, they aren’t as noticeable as some of the other patterns. Some spade designs are waveform. They mix up the aesthetic of the soundproofing giving a more interesting look to your room.
Grid	The grid design has wedges but is in lines of three forming a set. These sets are small and square in shape which together gives the grid acoustic panels their name. They are more aesthetically pleasing than the other acoustic foam designs. Thus, make a good choice for home theatre system rooms.

Where Do You Put Acoustic Panels?

Where to place acoustic panels depends on the reflection points of your speakers. To start you need to find the reflection points of your speakers. This is measured from your tweeters. 

These are the small speakers that are embedded in column speakers or in box speakers. If you are unsure what these look like, then you should search for an image of them. 

According to Acousticgeometry.com, these are the areas of the room that cause the most interference and degrade the sound quality the most.

For this you will need an assistant. They will need to sit where you normally sit to watch your TV. Have them sit in position and then use a mirror. Move the mirror along the wall until your assistant can see the tweeters in the center of the mirror.

This is where you want to place an acoustic panel in the first instance. Mark that spot with painter’s tape. Then repeat on the other side. Now you’ve marked your first reflection points on the walls. 

You should have two reflection points to the right and left of where you sit to watch your TV. These are the ideal place to put your first acoustic panels. You should use diffuser panels in these spots. Absorbing acoustic panels work ok. But, not as good as diffusers.

Sound reflections occur on all 4 walls. So, you should place a sound diffuser on the front wall and back wall. It may be necessary to use a smaller sound diffuser acoustic panel so that it fits first together with your TV. This is fine. 

You can also mount it horizontally. Sound moves in three dimensions, and it saves space. Corners make sound bounces worse. Therefore, you should put sound absorbing acoustic panels in each corner. 

You can place these on the back wall close to the corners. And on the side walls close to the corner in the front of the wall. That way you stop side to side reflected sound waves and those bouncing front to back.

This will definitely improve the sound in your room, and in some cases be all that you need. Each room is unique, however, and other acoustic panels can be further used if you need them. These are ceiling absorber panels.

These are called clouds. You can place two directly above your TV, and two above your seating area. Some homes have ceiling grids. For these, you can get sound-absorbing tiles to further improve the sound in your room.

If this is still not enough, it’s time to bring out the big guns. Not really big guns. But, you can add:

• A diffuser panel directly in the corners of your room.
• A horizontally mounted diffuser between each of the vertically mounted diffusers.
• Add additional clouds to the ceiling.

As you can see, it is not necessary to cover your entire room with acoustic panels to get great acoustics. Remember, the size and number of acoustic panels you will need depends on the size and shape of your room. As well as, windows and doors. 

What Are Acoustic Panels Made Of?

According to Wikipedia, acoustic panels are made from mineral wool, fiberglass, cellulose, open-cell foam, or combinations of these.

Do Acoustic Panels Lessen Outside Noise?

Soundproofing a room and improving the sound within a room are two separate endeavors. It is a common misconception that acoustic panels will reduce outside noise within a room. 

People assume, myself included, that the acoustic panels that you see in recording studios make the room quieter. Because you need no noise in a recording studio to record music. 

But, deadening outside noise is done through other means, according to Acousticalsurfaces.com. The main way is through This comes from people who have been in sound studios which are very quiet. 

The main ways are to:

• Add and increase the mass and density of the wall to make it heavier.
• Building them all so that there is space between the outer edge of each wall.
• Reduce the vibration that occurs in the wall.
• Renovating the room with soundproof windows and doors.
• Renovating the floor to be more soundproof.

The ideal people to talk to in this regard are builders and construction companies. They will have the contacts and expertise to build walls which fulfil the above requirements. 

If your house is already too loud then there is nothing you can do that will have much impact in regard to reducing outside noise. Barring, renovating the room. So, the answer is a big fat no.

How Much Do Acoustic Panels Cost and Which Ones Are The Best?

Acoustic panels of all varieties range in price from about $100 an up. You can get discounts by buying large quantities. Some options include 24 small-sized panels for $150.

The best acoustic sound panels according to an extensive review by musiccritic.com are the:

In Conclusion

Acoustic panels absorb reflected sound that improves the sound within a room. Most applications are in rooms with home theater systems and sound recording studios. Also, they do not dampen outside noise.

Sources

• Wikipedia: Tweeter
• Acousticgeometry.com: Homepage
• Acousticalsurfaces.com: Soundproofing vs Sound Absorbing – What’s the Difference?
• Wikipedia: Acoustic panel
• Musiccritic.com: 6 Best Acoustic Foam Panels in 2020