Reflections, reverberation, flutter, standing waves, and echo can make the most enjoyable movie sound horrible and the best singer sound gravely. If that sounds like your home studio or theater, you may want to consider some acoustic panels. The big question then becomes, “How many acoustic panels do I need?”
The size, shape, and purpose of the room determine the number of panels needed. Low coverage is about 10% of the wall and ceiling surface, medium around 20%, and high treatment 30% or more. Some home recording studios may need 75% or more, so start small and work up until it sounds right.
In this guide, we discuss how to determine the amount of acoustic treatment required, factors that affect the calculation, and where best to place the panels for the best results. We also explain how to calculate the amount of treatment, how to use an acoustic panel calculator, and panel spacing. Our goal is to provide you with the information and tools to determine how many acoustic panels you need for your home studio or theater.
Contents (Jump to Topic)
- How Much Acoustic Treatment Do I Need?
- Factors to Consider When Calculating the Number of Acoustic Panels
- Where to Place Acoustic Panels for Better Sound Quality
- How to Calculate How Many Acoustic Panels I Need?
- How Far Apart Should Acoustic Panels Be?
- Acoustic Panel Room Calculator
- How Many Acoustic Panels Do I Need: Example
- Can You Have Too Many Acoustic Panels?
How Much Acoustic Treatment Do I Need?
The amount and type of acoustic treatment depend on the room’s dimensions, shape, and what you need the panels to treat. A home studio used to record audio clips has different requirements than one used to record soundtracks from musical instruments. The same applies to the home theater too. A 10’x10’ theater with stereophonic surround sound has different needs than one with a monodirectional speaker.
You may have heard or read that 60sqft of treatment per surface is best, maybe 3% of the cubic volume of the room, or 45% of the surface is the optimal coverage, and that may be true for specific rooms or purposes.
Many use RT60, the reverberation time it takes soundwaves to decay 60dB to estimate the number of panels. However, each room and purpose should be treated as unique. If only low or light coverage (10%) is required to treat a room, why cover and pay for 45%? A 10’x10’ room with an 8’ ceiling has a volume of 800 cubic feet, 3% is 24sqft of treatment for the room, which is less than 10% of the surfaces. Additionally, the 60sqft may be 60% or more of the wall surface which is overkill for most people’s needs.
Low or light treatment (10%) may be all that is required to address the noise that is interfering if it is correctly placed and spaced to cover the reflection points. Medium coverage of 20% of the wall or ceiling surfaces may catch all of the reflection points between the listener and speaker, so more coverage isn’t necessary. High treatment of 30% or more of the surfaces being covered is usually more beneficial for high-end surround sound systems or home recording studios.
A small 10’x12’ or 10’x10’ room will usually benefit from treatment on the four walls and possibly the ceiling too. The amount depends on the room’s purpose and the number of sound sources. If you identify the reflection points or zones, center on the listener’s ear height, and calculate the area 2’ above and below that height, that should be all the treatment you need for most home studios or theaters. You may choose to treat only a portion of the reflection points by spacing the treatment out in a symmetrical and aesthetically pleasing pattern. Thus, addressing the noise problem and being easier on the budget.
Factors to Consider When Calculating the Number of Acoustic Panels
Acoustic treatment can be absorbers, traps, diffusers, or clouds. The type, size, and amount depend on the room dynamics and what you intend to use the room for. It also depends on where the listening or monitoring occurs, the ceiling height, furniture, reflection points or zones, wall surfaces, plus the source or sources of sound. Consider the room and your purpose when calculating treatment.
Small rooms mean shorter distances for sound waves to travel between sound source, reflection points, and the listener or monitor. This creates a meniscal time delay between direct and reflected sound wave reception, which will muddy, dirty or garbled sound making it difficult to understand. It can also make one feel uncomfortable or closed in as our brain uses the reflected sound to identify proximity.
Large or long rooms mean the sound waves must travel further between direct and reflected waves which can produce reverberation and echo, as can high ceilings and parallel walls. Placing absorbent panels and diffusers where the reflections occur will help dissipate the reflected sound waves and improve the listening enjoyment.
Hard surfaces such as drywall, masonry, and hardwood reflect or deflect sound waves causing sounds to resonate more and for a longer time. Soft surfaces like carpet and plush furniture absorb sound waves, helping to shorten reverb time and dissipate the noise. The greater the amount of soft furniture in a room, the less treatment required.
Low 7’ to 9’ ceilings have quicker reflection times than higher ceilings and will muddy the sound more. The higher ceilings allow for longer sound wave travel, increasing the length of reverb time and echo. Low ceilings are easier to reach and treat than higher ones, which may need to be treated with suspended cloud panels.
The Source of Sound
The source of the sound needs to be considered. Vocals, instrumentals, and loudspeakers are different sources of sound that, along with volume, may need to be treated differently, so the room’s purpose comes into play here too. The type, orientation, and location of the sound source influence the amount, type, and location of the treatment required.
High and mid-range frequencies are often easier to treat than low range. Speakers mounted on shelves, into ceilings, waist height, or at floor level project noise at different levels and require treatment, and will have different reflection points too.
Type and Size of Acoustic Panels
Acoustic panels absorb or diffuse soundwaves and range from 3/8” to 6” thick. They are commonly used to treat walls and ceilings. Thicker or deeper panels are used as traps or clouds and run up to 12” or thicker. Traps are used where two walls or the ceiling and walls meet to address standing waves of sound, while clouds are commonly suspended over monitors or mixing stations.
Absorbing panels absorb sound energy and convert it to heat, helping to dissipate the noise and slow the reflection. They absorb and eliminate some or all of the soundwave to quiet the noise. Diffusers alter the direction and timing of sound waves by diffusing, deflecting, and scattering the waves to improve the clarity of sound. A diffuser helps to reduce echo and standing waves while keeping the sound alive.
Mass marketed foam panels come in a variety of profiles, shapes, sizes, and thicknesses, and also a limited selection of colors. Professionally made or DIY panels often have a core of stone wool or fiberglass insulation and, while available in different shapes and sizes, frequently are 2’x4’ and 3” to 6” thick. They are also wrapped in a wide choice of colored and textured fabrics. DIY and professional panels can be whatever size required.
A major consideration is the first reflection points or zones, which is where the sound from the speakers hits the walls, floor, or ceiling first. The sound reflects off and then proceeds to the listeners’ ears, muddying the sound. The side walls are a good place to start, treating the reflected points on both sides decreases the reflected noise, and may be enough for your needs. The back and front walls are next, plus the ceiling, before moving on to the corners.
Where to Place Acoustic Panels for Better Sound Quality
The first sound you hear is the direct line from the speaker to your ear. A split second later, you’ll hear the sound that reflects first off of the surface closest to you, either the floor if you’re sitting or the ceiling if you’re standing. Although, it may be off of the wall behind you if you’re positioned close to one. Regardless, the first reflections off the floor, ceiling, and four walls will find you with a slight time delay to the direct sound.
The first or primary reflections arrive so close to the direct wave that they muddy what you hear, and can make it difficult to hear the sound clearly. As no two situations are the same, there is no blanket solution, although a blanket can be part of the solution. Placing absorbers and diffusers where first reflections occur is a great way to clean up the sound and reduce reverb and echo.
Panels should be at the height of the listener’s ear or the monitor. If you’re sitting in a home theater, the panels should be 3’ to 4’ above the floor, and 5’ to 7’ if standing or perched on a barstool in a home studio. Place acoustic panels where they will catch the first reflection from the sound source or sources. Check out my article about where to place acoustic panels for an in-depth explanation.
To find the reflection point or zone, sit, perch, or stand where you normally would be to listen, or where the monitor will be stationed. If there’s more than one position, check for each. Have a helper move a mirror along the walls, ceiling, and floor and mark the surface where you begin to see the speaker reflected and then no longer see it. Do that for each surface, including the one behind you – you’ll have to turn and face that wall though. The area between the marks is the reflection point that needs to be treated initially.
How to Calculate How Many Acoustic Panels I Need?
The area identified by the mirror as the first or primary reflection points or zones needs to be treated to clean up the reflected sound. The more of that area treated, the better the sound quality heard. Additionally, you may want to treat corners for bass, reverberation, echo, and standing waves. So, the best way is to calculate the reflection area and surface area of the wall, or use an acoustic panel room calculator to identify the percentage based on low, medium, or high treatment.
My first step is to calculate the reflected area by multiplying the distance between the marks on the walls by 4’ to get the reflected area. I use 4’ as it will treat half the wall height when sitting, standing, or perched.
If the wall is 10’ long by 8’ high, that wall is 80sqft, the reflected area is 4’ by 4’, so 16sqft. Using two 2’x4’ acoustic panels will treat the reflection point and cover 20% (16sqft ÷ 80sqft) of the wall surface for medium treatment.
The size of the panels used and the area to cover determines the number of panels required. Divide the surface area to cover by the surface area one panel will treat to get the number of panels needed.
A 2’x4’ panel will cover 8sq ft, so two are needed to cover 16 sq ft of the reflection area.
A 1’x1’ panel treats 1sqft, so sixteen would be required to treat the same area. However, you may choose to use less of the smaller panels and space them in a pattern to minimize cost.
How Far Apart Should Acoustic Panels Be?
The dimensions of the room affect the distribution of the acoustic treatment and their efficiency to absorb or deflect sound. Placing all the panels tight together in a small area of the wall may address the first reflection point, but spreading the panels apart to form a symmetrical pattern increases the area of wall surface treated, and thus the efficiency of treatment. The larger coverage helps with the secondary and tertiary reflection, reducing reverb and improving sound quality.
The Area Principal determines the efficiency of the layout. The ratio of the perimeter of the panel pattern to the combined surface area of all panels on a wall identifies the efficiency (e). The perimeter of the pattern over the panel area (P/A) of the two examples above are a case in point:
Two 2’x4’ panels side by side have a pattern perimeter of 16’ (4+4+4+4) and a surface area of 16sqft (4×4), for an efficiency of 1.0 (16÷16). Spacing the panels so there is a two-foot space between them increases the efficiency. The pattern perimeter is now 20’ (6+4+6+4) to the 16sqft of panel coverage, for efficiency of 1.25 (20÷16), or 25% better.
The sixteen 1’x1’ panels placed tight together in a 4’x4’ pattern offer 16sqft of surface treatment or efficiency of 1.0. However, spacing them out in a checkerboard pattern creates a pattern perimeter of 24’ (8+4+8+4) to 16sqft for an efficiency of 1.5 (24÷16), or 50% greater.
The space between panels in the pattern of placement should be symmetrical and aesthetically pleasing, and not exceed the length or width of an individual panel. It should also be at the height of the listener’s ear or the monitor. While the side walls should have symmetrical patterns, the ceiling and floor may not. A carpeted floor with dense foam under pad coupled with an efficient acoustic array on the ceiling will also improve listening quality.
Acoustic Panel Room Calculator
An Acoustic panel room calculator is used to estimate and recommend the number of acoustic panels of a given size required to treat a room. The calculator uses the room’s dimensions and RT60 formula to identify the number of panels based on low, medium, or high surface coverage.
The calculated solution is for all four walls and the ceiling, you’ll need to determine the placement, arrangement, and number of panels per surface. Additionally, to avoid confusion check the unit of measurement of the calculator before you begin.
For most calculators:
- Input the length, width, and height of the room to be treated.
- Select the size of the panel. Use the option with the nearest square footage in the selection if it doesn’t have your exact size or shape.
- You may need to press ‘Calculate’ or the metrics may automatically provide you with the estimated number of panels for minimum (10%), recommended (20%), or ideal (30%) coverage, and the RT60 results using 2” thick panels. The terms and percentages may also vary from calculator to calculator depending on the developer.
Most calculators, like the one above, presume hard reflective surfaces such as drywall, hardwood, or concrete. Some calculators offer more options such as ceiling shape, door and window area, and type of surfaces, but the results will be similar if based on the RT60 formula.
How Many Acoustic Panels Do I Need: Example
The number of acoustic panels recommended by an acoustic panel room calculator depends on the room dimensions and the surface area or dimensions of the acoustic panels. Using an RT60 calculator such as the one we used above, the formula recommends the number of panels of the selected size required to achieve low, medium, and high coverage.
Using a 12’x20’x8’ room such as a living room or basement multi-purpose room, punch the numbers into the calculator. Select the panel size – we use 24”x48” as it’s a common DIY dimension. The calculator identifies 14 panels for minimum (10%), 16 for recommended (20%), and 21 for ideal (30%) coverage. You may want to start with low coverage and work your way up depending on sound quality and your budget.
Can You Have Too Many Acoustic Panels?
Acoustic panels absorb, diffuse, or trap sound waves to improve the sound quality in a room. While absorbers reduce the sound movement, diffusers send it in different directions to help keep the sound alive. Too much absorption in a room, however, can make for a dead-sounding space. The room feels and sounds wrong.
Covering the walls, ceiling, and floor with acoustic treatment isn’t recommended for home theaters. It may be desirable for a home studio though, where the aim is to create clean, crisp sound and not pick up reverb, echo, and other disruptive noises. The purpose of the room and what you wish to achieve with acoustic panels determine the type, number, and placement of treatment.
The number of acoustic panels needed for a home studio or theater depends on the room’s dimensions, the type and number of sound sources, and the size and kind of acoustic treatment used. Although each room is unique, a home recording studio usually requires more treatment than a home theater.
Identify and treat the reflection points, or calculate the percentage of coverage desired using an acoustic panel room calculator to identify the number of panels. Start small and add more as required.
Hopefully, you have a better understanding of how to determine the number of acoustic panels needed for your studio or theater.