Speaker Size Vs Room Size Calculator

Norvan Martin
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People have always debated speaker size vs room size and so there is a lot of confusion around the issue. In this article, we will look at speaker size vs room size because speaker size and room size must be matched. That means these two factors must be considered together to come up with the best room setup. We will both provide a speaker size vs room size calculator as well as explain why the dimensions of the room are so important.





Speaker Size vs Room Size Calculator Comparison Table

CriteriaSpeaker Size CalculatorRoom Size Calculator
AccuracyProvides accurate speaker size recommendations based on room dimensions, acoustics, and preferences.Estimates room dimensions accurately, considering factors such as shape and materials.
Ease of UseUser-friendly interface with straightforward input for room dimensions, preferences, and speaker placement.Easy-to-use interface for entering room dimensions, with clear instructions and options for additional details.
FlexibilityAdjustable parameters for speaker placement, room acoustics, and user preferences.Capable of accounting for various room shapes, ceiling heights, and construction materials.
Recommendations for Different Speaker TypesProvides recommendations for various speaker types (bookshelf, floor-standing, in-wall).Focuses on room dimensions and may not specifically recommend speaker types.
Integration with Speaker SpecificationsIntegrates speaker specifications for compatibility with recommended room size.Focuses on room dimensions and may not directly integrate with speaker specifications.
VisualizationsOffers visual representations or diagrams illustrating recommended speaker placement.May include visualizations of room dimensions and layout.
User GuidanceProvides guidance on optimal speaker positioning, room setup, and acoustic treatments.May offer suggestions on room layout and furniture placement with a focus on architectural aspects.

Calculator To Find the Right Size Speaker for Any Space

You shouldn’t choose your speaker size by guessing. Instead, you can use a calculator that makes it easy to calculate the proper speaker size vs room size. This ratio is called the Forward Aspect Ratio (FAR). 

The Forward Aspect Ratio (FAR) really defines the length and width of your speaker. Here’s how you can go about calculating it:

  1. Measure the length of your space at mid-depth.
  2. Measure the width of your space at mid-width.


  • FAR = length ÷ width.
  • Cov. Angle = 2 × arcsin(1 ÷ FAR)

(If you are using a calculator, you can arcsin is the sin^-1 button. We will explain exactly how you can use a calculator to calculate this below)

Find the Right Size Speaker for Any Space For Example

1. Measure The Length Of Your Space At Mid-Width

Measure your space at mid-width as below:

Measure The Length Of Your Space At Mid Width

2. Measure The Length Of Your Space At Mid-depth

Measure your space at mid-depth as below:

Measure The Length Of Your Space At Mid Depth

3. Calculate The Forward Aspect Ratio (FAR)

Calculate Forward Aspect Ratio (FAR) as length ÷ width

In this case:

FAR = 60 ÷ 45 = 1.33

FAR = 1.33

4. Calculate The Coverage Angle

Now calculate the coverage angle that the speaker must be able to produce to fill up the room. 

Cov. Angle = 2 × arcsin(1 / FAR)

In this case:

2 × arcsin(1 ÷ 1.33) = 97.5º

This means we need a 97.5º speaker.

An easy way to do this calculation is to use the calculator found at https://www.calculator.net/. With this calculator, arcsin is the sin-1  button.

calculatr speaker coverage angle

Forward Aspect Ratio

What If I Don’t Have The Right Speaker?

Our recommendation is to always complete this analysis before you buy your speakers. However, if you already have a speaker and it’s not quite right, you don’t need to worry as long as you have no more than a 3 dB error on each side. 

You can also do a comparison to see how far off you are. To do this, complete the following formulas and drop it into Google:

ABS((20 × log(FAR A))-(20 × log(FAR B)))

Where FAR A is the speaker you need and FAR B is the speaker you have.

If the result is more than 3, then that is over the allowance that we would want. This means you will have some unwanted wall reflections. You can consider subdividing your speaker or even reducing some of the reverberations with sound baffles

Why Is Speaker Size vs Room Size Important?

If your speaker size vs room size ratio is not correct, you may have issues in terms of reflections and modal issues.

For example, if the speaker driver is too small, the musical presentation will be poor, meaning it won’t be strong enough to cover the entire room. On the other hand, if the speaker driver is too large, you may end up with unwanted reflections or echoes. 

What Is The Correct Ratio Of Speaker To Room Size?

There are many factors to consider when thinking about the correct ratio of your speaker size to your room size. We talk about driver diameter, room volume, reflections, driver frequency, and more. All this must be considered when thinking about the correct ratio of sp3eaker to room size. 

Floor And Ceiling Reflections

Reflected sound waves from the floor and ceilings can cause a lot of muddiness in your overall sound quality.

Floor And Ceiling Reflections

If your speaker is too close to the ceiling or the driver is too large and powerful, it may cause reflections. Reflections are really time delays or echo that are caused by interference. You end up with distortion and sound effects you don’t want.

Reflections from the floor should also be considered because they reach your ears before the ones from the ceiling. This type of reflection also has a negative impact on your soundstage. 

Speaker Driver Diameter

If you have a subwoofer or woofer with a large diameter, for example, 12″, 15″, or 18″ subs, your room volume should be able to support this driver.

speaker driver diameter

If this is not done, you will have a lot of unwanted vibrations. If your low-frequency driver is too large, you may also need to low-frequency sound absorption technology such as bass traps or a Helmholtz trap.


There are several factors that should be considered when thinking about selecting a speaker to fit both physically and acoustically within your room. You should think about driver size, room volume, and so on. You should also use a speaker room-size calculator to assist. 

When considering room size and speaker size, you should also consider if there is any delay in the audio. Check out this speaker delay calculator to learn more. In addition, check out our guide on stereo speaker placement calculations and calculators to learn more about placing your audio system.

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Norvan Martin is the founder of BoomSpeaker.com. He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin