Speaker Enclosure Volume Calculator

Building a speaker box requires knowing the exact internal air volume — too large or too small and your speaker won't perform as designed. Enter your box width, height, depth, and wood thickness into the Speaker Enclosure Volume Calculator, then select your speaker diameter, displacement volume, and whether your enclosure is sealed or ported. You'll get the internal air volume in ft³ and liters, along with gross volume and port volume deductions.

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ft³

Volume displaced by the speaker driver (check specs)

Ported Enclosure *

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Results

Internal Air Volume

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Gross Volume

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Port Volume

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Internal Volume

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Frequently Asked Questions

How do I calculate the volume of a speaker box?

To calculate speaker box volume, subtract twice the wood thickness from each dimension to get internal dimensions, then multiply width × height × depth. Finally, subtract the speaker displacement and port volume (if ported) to get the net internal air volume.

Does a subwoofer box size make a difference?

Yes, box size significantly affects subwoofer performance. The internal air volume determines the resonant frequency and response characteristics. Too small reduces output, while too large can make bass loose and uncontrolled.

What size is a 0.75 cubic foot subwoofer box?

A 0.75 ft³ subwoofer box might measure approximately 12" × 10" × 8" internally (after accounting for wood thickness). External dimensions would be larger depending on the wood thickness used.

Does a bigger speaker box make it louder?

Not necessarily. While a larger box can extend low-frequency response, it may reduce efficiency at higher frequencies. The optimal box size depends on the specific driver's Thiele-Small parameters for best performance.

What wood thickness should I use for a speaker box?

3/4 inch (0.75") MDF or plywood is most common for subwoofer boxes. Smaller speakers can use 1/2 inch, while large high-power subwoofers may benefit from 1 inch or thicker for better rigidity and reduced vibration.

How do I find my speaker's displacement volume?

Speaker displacement volume is usually listed in the driver specifications (Vd). If not available, you can estimate it by measuring the speaker's depth and calculating the volume of the magnet assembly and basket.

What's the difference between ported and sealed enclosures?

Sealed enclosures provide tight, accurate bass with good transient response. Ported enclosures are more efficient and can produce deeper bass, but require precise tuning and larger box volumes for optimal performance.