Subwoofer box for a Chevy El Camino
The El Camino is a car-based pickup with a single bench seat. Behind it there is only a wedge-shaped space — shallow at the top, deeper at the floor — but the tiny cab means even a small box gives real bass.
Where the sub goes
- Behind the bench seat. A wedge: on 1978–87 cars about 6″ deep at the top and around 20″ at the floor. A box shaped to it takes one or two 10″–12″ subs. Check how far the seat can slide and recline first.
- Under the dash or in the kick panels. Small sealed boxes for 8″ subs — popular in restomods that keep the original look.
- In the bed. A weatherproof box under a tonneau cover has room, but it is outside the cab and gets no cab gain.
The same layout as a regular-cab truck — see the C10 guide.
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: a wedge box behind the seat
Ready-made boxes sold for 1978–87 El Caminos are about 14″ high, 6″ deep at the top and 20–23″ at the floor, and up to 42″ wide. Take a wedge 42″ wide, 14″ high, 20″ deep at the floor and 6″ at the top. With ¾″ walls the inside is about 40.5″ wide, 12.5″ high and 11.5″ deep on average — about 3.4 ft³ gross: two 10″ or 12″ sealed (0.75–1.5 ft³ each for a 12″) or one 12″ ported (1.5–2.5 ft³ net plus the port). Some of these boxes step down toward the back, so the real space is a little smaller; 1968–72 cars are different — measure yours.
Cab gain
A single cab is about the smallest closed space a sub plays into. Below roughly 70–80 Hz it lifts the bass strongly, so a thin sealed box sounds much bigger than it would at home.
Design it for your El Camino
Enter the gap with the wedge angle, filter the database for shallow subs, and the calculator checks that each sub fits, draws the box and gives you the cut list and DXF.
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 an El Camino?
Behind the bench seat in a wedge box shaped to the seat back, under the dash or in the kick panels, or in a sealed box in the bed under a tonneau cover. The cab is small, so space is the problem, not bass.
Can I put the box in the bed?
Yes, in a weatherproof box under a hard cover, but the bed is outside the cab: it gets no cab gain and the sound has to come through the rear wall or window. A small box in the cab often sounds deeper.
What subs fit behind an El Camino seat?
On 1978–87 cars, ready-made boxes for one or two 10″ or 12″ subs fit behind the seat: the space is about 14″ high, about 6″ deep at the top and around 20″ at the floor. Check the sub’s mounting depth, and measure with the seat in your driving position.