Manual The vented QUANTUM QSB enclosures feature a very compact design . With an impedance of 2+2 ohms each, the subwoofer can also be operated in 4 ohms or even in 1 ohm in order to get the maximum out of the amplifier. Thanks to the large voice coils (50 mm at the QSB6 and 64 mm at the QSB8 a..