How to make Cerwin Vega Vmax 124 4ohm hit harder?

Turn up the sub controls on the equalizer and if it has its own crossover filter for lowpass then dont use the amps crossover. You may be using double crossovers lowering the signal output slightly. If this doesnt help then turn up the gains slightly on the amp. Hifonics are over rated anyways. In fact they just recently became cea compliant. Any older model is most likely over rated and doesnt do the power it claims