This DSP driver you want is here.

DSP1 Driver

Acustika DSP1 for driver download click here..

DSP2 Driver

Acustika DSP2 for driver download click here..

DSP3 Driver

Acustika DSP3 for driver download click here..

NPD 50.6 DSP Driver

Nautilus NPD 50.6 DSP for driver download click here..
dsp