Speaker Box Volume Calculator
Calculate speaker enclosure volume from internal dimensions, minus driver displacement, plus ported-box port length.
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Volume the driver (and bracing) occupies inside — on the driver spec sheet.
Results
- Gross internal volume
- 70 L
- Net volume (after driver)
- 69 L
- Net volume (cubic feet)
- 2.437 ft³
Measure internal dimensions (outer dimensions minus twice the wall thickness). Compare the net volume with the driver's recommended sealed enclosure range (Vas/Qts based).
About Speaker Box Volume Calculator
Sealed mode multiplies the internal dimensions and subtracts the driver's displacement to give net volume in liters and cubic feet. Ported mode adds the required port length for a target tuning frequency using the standard Helmholtz round-port formula Lv = 23562.5·D²·Np ÷ (Fb²·Vb) − 0.732·D.
Common uses
- Check a subwoofer box design against the driver's recommended volume
- Find the port length to tune a build to 32 Hz
- See how a bigger port diameter changes the required length
Example
Input
50 L net box · 10 cm port · 35 Hz target
Output
≈ 31.1 cm port length
Limitations
- The port itself displaces volume and slightly detunes the box — subtract it and iterate for precise builds. Flared ports and slot ports need adjusted end corrections.