Powered vs passive subwoofers

The difference is simple: a powered subwoofer has its amplifier built in, and a passive one needs a separate amplifier to drive it. For almost everyone building a home system, the answer is a powered sub — but it's worth knowing why, and the few cases where passive is the right call.

The core difference

A subwoofer's driver needs a lot of power to move air and produce deep bass. The question is simply where that power comes from.

• Powered (active) subwoofer: the amplifier lives inside the cabinet. It plugs into a wall socket, takes a single low-level cable from your receiver's subwoofer output, and is ready to go. The amp is matched to the driver at the factory, so the two are optimised for each other.
• Passive subwoofer: no built-in amplifier. It's just a driver in a box with speaker terminals, and it stays silent until you connect it to an external amplifier powerful enough to drive it. Matching that amp to the sub is your responsibility.

Which one do you need?

For a home theatre or hi-fi system: powered. This isn't a close call. A powered subwoofer is simpler, self-contained, and tuned as a complete unit — you connect one cable, set a few dials, and you're done. It's why practically every consumer subwoofer, from a $150 Polk PSW10 to a reference SVS PB16-Ultra, is a powered design. If you're shopping for a living room, you want a powered sub, full stop.

The controls on a powered sub's back panel — gain, crossover, phase — are also what let you integrate it with your room. Dialling those in is the difference between boomy and seamless bass; the crossover, phase & gain guide walks through it.

When passive actually makes sense

Passive subwoofers aren't obsolete — they just belong to specialist setups where a separate amplifier is already part of the design:

• Custom and commercial installs. An integrator running several subs from a central rack of amplifiers wants passive units so the amplification is centralised and matched deliberately.
• Pro audio and PA. Touring and venue systems often use passive subs driven by dedicated power amps — for example JBL's SB2210, a passive commercial sub that needs its own amp.
• Car audio. Many car subs are passive drivers or loaded enclosures powered by a separate car amplifier — a completely normal arrangement in a vehicle, covered in best car subwoofers.

Outside of these, a passive home subwoofer means buying, matching, and wiring an amplifier you don't otherwise need — cost and complexity for no benefit.

How to tell what you're buying

The spec sheet gives it away instantly:

• A quoted amplifier wattage (e.g. “200 W RMS”) means the amp is built in — it's powered.
• A power cord and back-panel controls (volume, crossover, phase, a line/LFE input) confirm a powered sub.
• Only speaker binding posts, no mains lead, and often a “power handling” rating instead of an amp rating, means it's passive and expects an external amp.

On our review pages, a passive sub shows its amplifier as “Passive” rather than a wattage — a quick way to spot which is which across the database.

The bottom line

Building a home theatre or music system? Buy a powered subwoofer — it's simpler, self-contained, and what virtually every home sub is. Only choose passive if you already run (or are deliberately building) a separate amplifier for it. If you're still deciding on the sub itself, the Match Finder narrows it to your room and budget, or start with what a subwoofer is and does.