From dramatic distinction to dramatic design, Pioneer^s new GM-Series amplifiers are thrillers in every sense, pushing the limits of flexibility and functionality. Variable HPF (High Pass Filter) allows for adjustable frequency between 40 Hz to 500 Hz and greater car audio system flexibility according to subwoofer characteristics and personal listening preference. Bass Boost featured in the GM-A6704 and GM-A5702 can be set to levels variably from 0 to 12 dB for optimal bass. New Pioneer amps brilliantly integrate high-power performance superior to that of previous models in space-efficient sizes for flexibility of installation in various car cabins.