The VNC section of the project attempts to automatically regulate the tonal balance of the input signal to a tuned, consistent level using a tone control stage and several input variables. Real-time tone regulation is calculated by the VncControl object and gain is applied using the ToneControlVnc object. It considers these input variables:
Current speed
Current entertainment volume and announcement volume setting
Current roof state (open or closed)
Current fan speed
Tuned LUT’s which condition the control input signals
Current signal-to-noise in the cabin as computed by the NoiseEst object
The VNC section of the project operates in the following way:
The NoiseEst object generates a measure of signal-to-noise ratio using a cabin microphone signal compared with current entertainment audio
The VncControl object computes tone band (bass and treble) gain values to send to the ToneControlVNC object, based on LUT-conditioned data from the control signals and input from the NoiseEst object
The VncControl object also computes a gain value, applied by the VolumeEnt volume control object. The VNC gain stage serves the dual purpose of normalizing the tone gain (so there is not an overall level increase or decrease as a result of tone changes) and further regulation of the system’s overall gain. Please consult the VNC tuning manual for further information.