ANC (if equipped)
The Automatic Noise Control (ANC) feature reduces the level of occasional low frequency engine noises which compete with audio system playback.
The DACMC, built in to the ACM, determines the noise frequency to be canceled from the sound present inside the vehicle and by using engine data from the PCM.
While the engine is running, the ANC microphones monitor undesired noise in the passenger compartment. The microphones transmit this noise as analog signals to the DACMC inside the ACM. The signals are processed to create an inverted phase sound wave with the same amplitude as the original sound. This noise-canceling sound created by the DACMC is transmitted internally to the ACM outputs and externally to the DSP module over the Automobile Audio Bus (A2B) cable. The final output by the ACM and the DSP is sent as fluctuating AC voltage to the speakers.