Sprocket DeHum is a new VPI for the restoration of optical soundtracks.

Sprocket DeHum removes typical 24Hz or 96Hz "Buzz" noises (Hum fundamental with harmonics) automatically, using intelligent notch filters.

The "Analyzer" shows a detailed spectral analysis ranging from 20 to 30 Hz or 85 to 105 Hz, in which the noise peak can clearly be seen. A real-time "Learn" function analyzes the audio signal, defines the dominant harmonic of the disturbance and then creates a harmonically related filter set. This filter set is ordered by descending attenuation requirements. The operator can then move the "Complexity" fader to define the number of filters required to remove the disturbances.