Inside the Bose Nissan 370Z spare wheel subwoofer, there are two 4.5″ 2-ohm woofers. They appear to be mounted isobaric loaded, but there is no seal around the top plate which is held by 12 phillips-head screws. The round enclosure also houses the subwoofer amplifier.
There is also a 4-channel amplifier that drives the other speakers, as the 6×9 speakers in the doors and the small tweeters in the dash.
