Car Subwoofers and Enclosures

Sealed, ported or tube box: choosing the shape of your bass

A sealed enclosure gives tight, accurate bass in a compact box. A ported enclosure is louder around its tuning frequency but needs a bigger box. A tube enclosure is compact and fits corners and trunk edges. Loaded enclosures come with the subwoofer installed and tuned, which removes guesswork. Check the internal volume the driver maker recommends against the room in your trunk, and the size, since common sizes run from 8 to 12 inches.

Voice coils and impedance: wiring a sub to the amplifier

A dual voice coil subwoofer lets you choose the final impedance. Two 4-ohm coils wired in parallel give 2 ohms, and in series give 8 ohms. Two 2-ohm coils give 1 ohm in parallel and 4 ohms in series. The amplifier must be stable at the load you pick, and its RMS output at that load should match the subwoofer's RMS rating.

Questions about Car Subwoofers and Enclosures

Is a bigger subwoofer always louder?

No. Output depends on power, enclosure and the driver's sensitivity. A smaller sub in a well-matched box with enough power can outplay a larger one that is underpowered or in the wrong enclosure.

Can I run two subwoofers on one amplifier?

Yes, if the combined impedance stays within what the amplifier supports and the amplifier has enough RMS power for both. Work out the final load before wiring, and use a mono amplifier rated for it.

Do I have to put a subwoofer in a box?

In nearly every install, yes. Without an enclosure or a sealed baffle, the sound from the back of the cone cancels the front, so bass is weak and the cone is poorly controlled. Use a box built for that driver or a loaded enclosure; only free-air models are designed to fire through a sealed rear deck.