Good condition bass impact restorer/electronic crossover. Digital fundamental restoration system with subsonic filter. Rack mount. On front panel there is a detection ratio dial, PCA in/out switch, circuit select hifi/video switch, tape monitor/external processor switch, subwoofer level in/out switch, hi/low balance dial, and a power switch. The electronic crossover is 18db/octave Butterworth, and the x-over frequency is changeable via replaceable chips any DIY enthusiast can make. I'll include a 70Hz chip and a 1800Hz chip if I can find them. Try it on your LFE channel- it rocks! I imagine it would also be incredible to use with bass shakers. I don't have the original box or manual, but I'll package it well and info can be found online. Price is $55 plus shipping. Trades considered: X-Box stuff, LD AC-3 demodulator.