The SSM2000 is an advanced audio noise reduction system based on proprietary HUSH® circuitry. HUSH combines a dynamic filter and downward expander to provide a high level of effectiveness without the sonic artifacts normally associated with noise reduction systems. In addition, an Adaptive Threshold circuit detects nominal signal levels and dynamically adjusts both thresholds, thereby providing optimal results regardless of pro-gram source. Since it is a single-ended system, HUSH can be used on virtually any audio source, including audio and video tapes, radio and television broadcasts, or any other source with objectionable noise. The SSM2000 can be used with Dolby encoded sources with excellent results. A key feature is direct access to the Voltage Controlled Amplifier port enabling additional functions such as dc volume control, automatic level compression, etc. with minimal external circuitry.