The SYMPHONY12-2 ( 12 XLR Microphones/ Line, DSP, USB ) is very versatile mixer offered at very economical prices, now they come with built in heavy duty transformer which is much more durable and stable then external adapters, these are very clean sounding babies and offer Individual Gain, Bass, Mid, High Aux, Pan, Controls and Digital 16 Bit Effect Processor with display, XLR Balanced Outs and TRS Unbalanced outs. Individual PFL, Echo, Peak, LEDs on each inputs are provided. Phantom with LED indicators is provided for connecting hihj quality condenser mics for great sonic performances and voice pickup from distances. The SYMPHONY12-2 series come with built in USB, you can directly play songs from the USB and the USB functions include REW, FF, Play, Pause and Repeat , the display indicates the USB functions