Ready-made subwoofers are a fast, easy way to achieve better bass. The manufacturer already has built the box and installed an appropriate speaker. Some ready-made enclosures have as many as three subs in them. You pick the style and size you like, and match it to your amplifier, your available space, and the rest of your system.
In sedans, ready-made, non-amplified subwoofers usually go in the trunk. If you're feeding it adequate power, the bass it produces will be strong enough to penetrate through the back seat. Just connect the speaker wires from the amplifier and secure the enclosure with straps or brackets. Make sure you don't limit access to your spare tire, or cut through the gas tank or brake line if you drill holes for brackets.
Powered subwoofers
Powered, or amplified, subs offer an ease-of-use that's handy if you drive a rented or leased vehicle. Because of their portability, these subs can be removed quickly if you sell or exchange your vehicle. They also take up less space than a separate amplifier and subwoofer.
If you're installing a subwoofer that comes with a built-in amp, you won't have to hook up speaker wires, but you will have to install a patch cord (or tap into your speaker leads for the input signal). You'll need an amplifier wiring kit for power, ground and turn-on leads. That usually means you will need to run wire under your seats.
Be extra careful to anchor a subwoofer in a hatchback, station wagon, or sport utility vehicle. It could become airborne and injure someone if you stop suddenly.
