The DMM 4/2/4 is a digital automatic stereo mixer with four balanced microphone inputs, two stereo AUX inputs and one stereo recording output and one stereo master output. A unique and highly effective, intelligent mixing algorithm automatically allocates gain among the system microphones (NOM attenuation). A special noise detection function and the “Noise Sensitive Threshold” algorithm (NST) prevent accidental activation of input channels. The mixing algorithm also includes a “Last Mic On” function and a “Best Mic On” mode. Each input channel features low cut as well as LF and HF shelving filters. A dbx® compressor/limiter is included in the algorithm to provide a significant improvement in sound quality. Each channel offers switchable gain (Mic/Line, Mic-Lo/Mic-Hi), switchable phantom power, and an incremental level control with LED level and peak hold display. The automixing and ducking functions can be enabled and disabled for each channel separately. An expansion connector enables multiple DMM 4/2/4 mixers to be daisy-chained for larger systems. A rear-panel control I/O port provides logic in and outputs for controlling external devices. Also available on the rear side is a RS 232 interface for PC connectivity.