In Phase XTB-828R Underseat Subwoofer

The In Phase XTB-828R is a compact underseat subwoofer designed to add proper low-end punch to your car audio without taking up boot space. It delivers 300W peak power through a Class D amplifier, which keeps things efficient whilst giving you enough oomph for bassier tracks. The passive radiator setup helps extend the low frequencies, so you're getting fuller sound even from a relatively small unit. At 25.5cm high and 25cm wide, it tucks neatly under most front seats, which means you're not sacrificing storage or passenger room.

The Class D amp runs cooler and draws less power than older designs, so it won't hammer your battery on short journeys. You can wire it into your existing setup without a massive overhaul, and it pairs well with standard head units. The passive radiator does much of the heavy lifting for bass response, giving more output than expected from this size. It comes with a 1 year manufacturer's guarantee, so you've got backup if anything goes sideways. It won't shake windows like a full-size sub, but for its size, it's a solid upgrade.