If you're hunting for the right el camino subwoofer box, you've probably already noticed that the cabin doesn't give you much wiggle room. It's the classic struggle for any Elky owner. You've got that iconic silhouette—half car, half truck—but the interior is strictly a two-seater affair with a back wall that feels like it's practically touching your shoulder blades. Getting a decent sound system in there requires a bit of Tetris-level planning, especially if you aren't willing to sacrifice every inch of legroom just to get some low-end punch.
Most people start their audio journey thinking they can just toss a generic truck box back there and call it a day. While that might work if you're five feet tall and keep your seat bolted to the dashboard, it's usually a recipe for a cramped ride. The goal is to find or build something that fits the specific contours of the floor and the rear bulkhead without making the cabin feel like a closet.
Why the Shape Matters More Than the Size
The space behind the seat in a Chevy El Camino is deceptive. Depending on which generation you're driving—whether it's a sleek 60s model or the boxier G-body style from the 80s—the floorpan has different humps and slopes to deal with. A standard rectangular box is almost always a bad idea. It leaves huge gaps of wasted space at the bottom or top because the back of the seat is angled.
To really make an el camino subwoofer box work, you need a wedge-shaped enclosure. This allows the back of the box to sit flush against the rear wall while the front slopes forward to match the natural recline of your seats. If you get the angle right, you can actually fit a surprisingly large enclosure without moving your seat forward an inch. It's all about following those factory lines.
Shallow Mount Subs are Your Best Friend
Gone are the days when "slim" subwoofers sounded like a wet cardboard box hitting a fence. Modern shallow-mount technology has come a long way. If you're trying to keep the box thin, you should definitely look into 10-inch or 12-inch shallow drivers. These usually only need about 3 to 4 inches of mounting depth, which keeps the total thickness of your el camino subwoofer box manageable.
If you insist on using a full-sized subwoofer, you're going to have to get creative. Some guys build the box with a "step" in it or use a "down-firing" setup where the sub points at the floor. But honestly, for an El Camino, a front-firing shallow sub in a sealed wedge is usually the cleanest look and the easiest install.
Exploring the Smuggler's Notch
Every El Camino owner eventually looks at that "Smuggler's Notch" under the floorboards behind the seats and thinks, "Can I put a sub in there?" The answer is yes, but it's a bit of a project. That hidden compartment is great for storage, but it can also serve as a perfect "stealth" location for a subwoofer.
Building an el camino subwoofer box into the floor well takes a lot more work than a behind-the-seat unit. You have to worry about vibrations against the metal body and making sure the seal is airtight. Some people build a custom fiberglass enclosure that drops right into that hole. The benefit? You keep all your behind-the-seat storage space for your jack, tools, or whatever else you carry. The downside? You might get some nasty rattles if you don't use a ton of sound-deadening material like Dynamat.
Sealed vs. Ported in a Small Cabin
Because the El Camino cabin is so small, you really don't need a massive ported box to get loud. In fact, a ported box is usually too big to fit comfortably anyway. A sealed el camino subwoofer box is almost always the way to go.
Sealed boxes are smaller, which is the primary win here. But they also provide a tighter, more accurate bass response. In a tiny cabin, the "cabin gain" (the way sound waves reflect off the close interior surfaces) naturally boosts the low frequencies. If you put a huge ported box in there, the bass might end up sounding "boomy" or muddy. A sealed 10-inch sub will usually sound punchy, clean, and plenty loud enough to vibrate your rearview mirror right off the glass.
Choosing the Right Materials
If you're going the DIY route, stick with 3/4-inch MDF (Medium Density Fiberboard). It's the gold standard for a reason—it's dense, it doesn't vibrate much, and it's easy to work with. Some people try to save weight by using thinner wood, but you'll regret it when the box starts flexing under heavy bass hits.
If you're feeling adventurous, you can use fiberglass for the back of the box to mold it perfectly to the floor's shape, then use MDF for the front baffle where the sub actually mounts. This hybrid approach lets you squeeze out every cubic centimeter of air volume possible. Just remember: air volume is king. Even the best subwoofer will sound like garbage if the box is too small for its specs.
Dealing with Seat Clearance
This is the part everyone forgets until they're trying to bolt the seat back down. You need to account for the "travel" of the seat. If you have power seats, there are motors under there that might hit the box. If you have manual seats, you need to make sure the adjustment bar can still move.
When you measure for your el camino subwoofer box, move the seat all the way back to your comfortable driving position. Then, measure from the back wall to the seat frame at both the top and the bottom. Give yourself an extra half-inch of "breathing room" so the seat fabric isn't constantly rubbing against the box or the subwoofer grille. Speaking of grilles—use them. Nothing ruins a sub faster than a seat bracket poking a hole in the surround when you slide the seat back too fast.
Amp Placement Ideas
Once the box is in, you still have to put the amplifier somewhere. If your el camino subwoofer box is small enough, you might be able to mount the amp directly to the side of it. However, if space is at a premium, look under the seats. Most El Caminos have just enough room under the driver or passenger seat to tuck away a compact Class D amplifier. These newer amps run cool and stay small, making them perfect for tucking out of sight. Just make sure it gets some airflow so it doesn't overheat during a long summer cruise.
Finishing the Look
An unfinished wooden box looks out of place in a classic interior. You'll want to wrap your el camino subwoofer box in carpet or vinyl that matches your interior. Most upholstery shops sell "automotive grade" carpet that's stretchy and easy to glue down. If you have a custom interior with leather or high-end vinyl, try to find a matching material. A well-integrated box looks like it belongs there, whereas a raw wood box looks like a weekend accident.
Don't forget the wiring. Run your power and signal cables under the carpet if you can. There's nothing that kills the vibe of a clean interior like a mess of "spaghetti" wires running across the floorboards. Take the extra thirty minutes to tuck them away properly.
Final Thoughts on the Build
At the end of the day, adding an el camino subwoofer box is one of the best upgrades you can do. These old trucks aren't exactly known for their quiet cabins, and a little bit of bass helps drown out the road noise and the drone of the exhaust. Whether you buy a pre-made slim box or spend the weekend breathing in MDF dust to build a custom one, the result is worth it.
Just keep your measurements tight, choose a sub that matches your air volume, and don't forget to protect the speaker face. Once you're cruising with that full-range sound, you'll wonder how you ever sat in that cabin with just those tiny dash speakers. It changes the whole driving experience, making those long hauls or local car meets just that much more enjoyable.