The D-3500 is a digital feedback management and EQ device featuring 30 parametric filters with Automatic Frequency Restoration (AFR). AFR cuts the problematic frequency when feedback appears and restores it when feedback subsides. It offers programmable delay, high/low pass filtering, a gate and limiter, 24-bit resolution, and sample rates up to 96 kHz. It stores up to 100 programs and can be linked via MIDI or the D-Net System Interface. Discontinued.