Box planning
Universal enclosure lab
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Universal enclosure calculator
Use specifications for any brand. These are preliminary volume and port-length tools, not verified construction plans or power-handling simulations.Calculates sealed net volume from the driver’s Vas and Qts for your selected system Qtc.
Choose quantity, sub size and tuning. Get a starting box volume and port size. Already know your total net airspace? Add it below.
I already know my box volume (optional)
Port shape & advanced settings (optional)
See your box in 3D
Open-top layout preview. Red traces the port path. Folded slots turn along the rear wall; the center option splits left and right into equal sub chambers. Rotate the view or adjust the dimensions below.
KONG-inspired 3D model: red cast basket, black vented motor and NX LVL dust cap. Driver proportions are illustrative; confirm mounting dimensions and vehicle clearance before building.
Layout mockup, not a cutting plan. Uses nominal sub diameters and ¾-inch walls. Folded slots share enclosure walls; internal port walls are included in their volume calculation. Driver depth, cutouts, bracing and actual displacement still need confirmation. Straight square, rectangular and round options use standalone ports.
Enter an independently selected sealed volume per driver, or estimate it from Vas and Qts. Quantity scales both chamber totals. You choose front-chamber tuning; this is not the predicted peak or playable frequency range. Chamber ratio and port area are planning assumptions, not optimized recommendations. Nominal sub size does not establish required airspace or physical fit.
Advanced alignment controls
Select the actual layout first. This preliminary solver supports parallel-tuned boxes only, with each chamber venting outside. Enter independently modeled chamber volumes and tunings. Series-tuned boxes need a coupled model and are not supported here.
Rear chamber
Front chamber
Where do I find Fs, Vas and Qts?
Use the Thiele/Small parameter table on the subwoofer manufacturer’s specification sheet. Vas is compliance volume, Qts is total Q and Fs is free-air resonance. Use parameters for one driver; quantity is handled by the calculator.
The 4th-order planner multiplies the sealed net airspace per subwoofer by quantity, then applies your selected chamber ratio and tuning. Gross results place driver displacement in the selected motor chamber and port air-column displacement in the ported chamber; add bracing and port-wall material displacement. Final response, shared-wall slots, bends, compression and power handling still require proper modeling and measurement before cutting wood.
Already know your box measurements? Open advanced calculator
Sealed chamber
Ported chamber
Rear chamber
Front chamber
Generic cubic-foot volume only. Use internal measurements and verify all displacement before building.