Attention Mac users: this DJ software, DJ-1800 on the picture was designed to you exclusively. It has four separate digital file player, and four channel on the mixer consequently. The crossfader itself is a four-channel solution, and all the mixer channels have high/low EQ. BPM calculation is implemented, too. The program handles multiple audio outputs, and every knob and fader can be controlled from outside, by MIDI controller units. Costs 80 USD, here is the site where the transaction could take place.