Sealed or bass-reflex?
A sealed enclosure adds an air spring behind the cone. Bass-reflex uses the air resonance in a port to change the low-frequency response. Below tuning, cone excursion can rise rapidly — check it at your intended drive level.
GREAT BASS STARTS WITH A PLAN
Calculate the sound.
Design the enclosure.
From driver parameters to a box you can build. Acoustic simulation, port tuning and panel dimensions in one place.
● Free online designer · private project librarySIMULATION / 10–500 Hz
Frequency simulation
● A
BUILD / 3D
Enclosure model
Check before building
Panel cut list
| Panel | Qty | Dimensions [cm] |
|---|
Rectangular box: front and rear cover the top, bottom and sides; top and bottom cover the side edges. A trapezoid has a vertical front and sloped rear; side depths are shown as top → bottom. Bevels and joinery require a workshop drawing. Slot ports use four separate duct walls. All dimensions exclude cutting allowance and saw kerf.
LEARN / DESIGN / BUILD
From driver data to an enclosure
Start with Thiele–Small parameters from documentation or measurements. Select the enclosure, compare curves and check the limits. Outer dimensions are derived from net volume, ports and the volume occupied by internal components.
Net means the air space
Net volume excludes the driver, bracing and ports. The internal displacement field should include all drivers and bracing; do not add the port walls again. Port air and duct-wall material are added automatically. The interactive model checks frame diameters, port placement and depth clearance. Driver baskets are conservatively treated as cylinders; check the manufacturer drawing before construction.
What do the graphs show?
This small-signal model supports 1–4 identical drivers in one chamber, wired in parallel or series and radiating in phase. Enter T/S and mounting parameters for one driver; power and displacement are totals for the enclosure. SPL: half-space at 1 m with RMS voltage. Excursion and port velocity: peak values. F3 is the lower −3 dB crossing relative to the peak between 10 and 500 Hz. Vehicle cabin response, thermal compression, nonlinearities, sealed-box leakage and standing waves are excluded.
How do I use the cut list?
Rectangular box: front and rear cover the top, bottom and sides; top and bottom cover the side edges. A trapezoid has a vertical front and sloped rear; side depths are shown as top → bottom. Bevels and joinery require a workshop drawing. Slot ports use four separate duct walls. All dimensions exclude cutting allowance and saw kerf.
Model reference: Janne Ahonen — Electroacoustic modelling of the subwoofer enclosures. CarBoxLab: ρ = 1.2 kg/m³, c = 343 m/s.
From a design to an installation
CarBoxLab is created by Sound Audio System. Need measurements, a custom enclosure or installation in your car?
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