Q201A 20 cm (8) Active Subwoofer System Output Power 100/200 Watts The very slim QUANTUM Q201A system and the somewhat more spacious Q202A are equipped with a 20 cm special woofer and a real Class A/B amplifier. Both have an aluminum cast heatsink with excellent cooling properties, which optimally cool the integrated amplifier inside. Ideal for small cars, sport coupes and convertibles, the two active woofers find a place anywhere, be it under or behind the seat or in a storage compartment in the boot.