Build the box that actually fits your ride.
Pick your exact vehicle, get real factory cargo dimensions, computed sealed/ported box math, and an honest fit-check — before you cut a single piece of wood.
See What Fits →
11 free tools, built on the same data
The vehicle and driver databases, connected to real box math.
Design & build your box
Box Builder
Pick your vehicle and a real subwoofer from the database — get a computed sealed or ported box with real external dimensions, an honest fit-check against your vehicle's actual cargo space, and a build checklist with a cut list nested on a real 4×8 sheet — in 1/16" fractions you can actually cut, not decimal conversions.
Net Volume Helper
"Box volume" usually means net internal airspace, not outside dimensions — though some brands publish it gross, and Box Builder converts those per brand. Convert external dimensions to net volume, accounting for wall thickness, driver/port displacement, and bracing.
Port Tuning Calculator
Enter your box volume and target tuning frequency, get the port length to cut — round or slot port, with a port-area check against the 12-16 in²/ft³ guideline and a forward-verification of the resulting tuning frequency.
4th-Order Bandpass Estimator
Starting-point chamber volumes and port length for a 4th-order bandpass design. Explicitly NOT a full simulator — verify in WinISD/BassBox Pro before cutting wood.
Doors & speakers
Factory Speaker Locations
Factory door speaker sizes, mounting depth, adapter needs, and every other factory speaker location (rear deck, dash tweeters, soundbar, kick panel) — then a printable fitment checklist for your upgrade.
Door Fitment Calculator
Upgrading a factory door speaker? Pick your vehicle and door, pick a coaxial or component set from the database, and get an honest depth-clearance check — fits, needs a spacer, or doesn't fit.
Wire it, fix it, compete
Wiring Calculator
DVC or SVC, 1-4 subs, series or parallel — pick your driver from the database and get the real final impedance at the amp, a wiring diagram, and a safe-load check.
Electrical & Power Calculator
What your amp actually pulls, what wire gauge survives it, what fuse protects that wire, and whether your charging system can feed the whole thing — the part of a build that gets skipped most and causes the most real damage.
Troubleshooting
Built the box and something sounds wrong? Match the symptom to a sourced, cross-validated cause and fix — buzzing, chuffing, boomy or weak bass, all of it.
Class Calculator
Orientation only, not a scoring tool — see which dB Drag Street class your woofer/amp combo lands in, plus a direct link to MECA's own official class calculator.
Find an SPL Meet
New to competing? The real sanctioning bodies, event-finder sites, and what to expect at your first burp or Bass Race — burps vs. musical formats, Term-LAB basics, all of it.
Which box type do you actually need?
Three real build styles, cut open so you can see what's inside.
Sealed
One airtight chamber. Tighter, more accurate bass and the most forgiving box to build — no port to tune.
Ported
Adds a tuned port for more output and deeper extension than sealed — at the cost of a longer, less forgiving build.
4th-Order Bandpass
Two chambers, one sealed and one ported, working together. Loud in a narrow band — built for SPL, not accuracy.
Open a Shop Ticket
Vehicle missing from the list, can't find your driver or sub, or just got something to say — write it up below. A real person reads every ticket.
Coming soon: a community build gallery — your ride, your box, your numbers. Not live yet, but if you've got a build you're proud of, drop it in a ticket below ("General feedback") and we'll keep it on file.