Subwoofer box for a Chevy C10
The C10 — especially the 1973–1987 square body — is one of the most popular trucks for restomods and custom audio. A regular cab leaves only a sliver behind the seat, so the box is thin and the subs are shallow.
Where the sub goes
- Behind the bench seat. A thin, angled box the full width of the cab with one or two thin-mount subs. Some builders move the seat slightly forward or swap to a thinner seat back to gain an inch.
- Under the bench. With a custom riser there is room for a low box; check that the seat still adjusts.
- Kick panels or under the dash. Small sealed boxes for 8″ subs keep the cab stock-looking.
- Extended and crew cabs. More room under or behind the rear seat, as in a Silverado crew cab.
Pick a sub for this spaceThe calculator opens with the vehicle and the space from this guide and lists the subs that fit there, each with its box. Then adjust the size to your own vehicle.
Example: behind the seat
Owners of 1973–87 square bodies measure the gap behind the bench at about 58–59″ wide and 15–16″ high; it is about 4″ deep at the top and 4–7½″ at the floor, depending on how far back the seat is. Take a wedge 58″ wide, 15″ high, 6″ deep at the floor and 4″ at the top. With ¾″ walls the inside is 56.5 × 13.5″ and 3.5″ deep on average — about 1.5 ft³ gross: two thin-mount 10″ sealed at the small end of their range (0.5–0.9 ft³ each) or two 8″, if their mounting depth fits the 2.5–4.5″ inside. 1967–72 trucks with the fuel tank behind the seat have less room — measure yours.
Cab gain
A regular cab is tiny, so it lifts the deep bass from a fairly high frequency. A thin sealed box behind the seat sounds much deeper in the truck than on a bench.
Design it for your C10
Enter the measured gap with the wedge angle, pick a shallow sub and the calculator checks that it fits, draws the box and gives you the cut list and DXF. See also the El Camino guide.
Model it for your own subResponse in your car, cone excursion and port air speed — free, no signup.Open the calculator →FAQ
Where does a subwoofer go in a Chevy C10?
Behind the bench seat in a thin, angled box with thin-mount subs, under the bench on a custom riser, or in the kick panels. A crew cab or extended cab has more room under the rear seat.
How much room is behind a C10 seat?
Only a few inches in a regular cab, and it depends on the seat, the year and how far the seat is moved. Measure with the seat in your driving position.
Sealed or ported in a C10?
Sealed: there is no room for a port behind the seat, and the small cab lifts the low bass a lot.