The audio subsystem of this console was heavily influenced by the technology of professional audio equipment and ATX motherboards, although it does contain some peculiar parts. The MCPX includes two audio components, the Audio Processing Unit and the Audio Controller Interface'.
The Audio Processing Unit or 'APU' is the dedicated audio processor and is composed of three sub-components:
- The Voice Processor or 'VP': A specialised circuit that can synthesise 256 voices at a sampling rate of 48 kHz. It also includes two DAHDSR envelope controls and various filters. Furthermore, 64 voices can be 3D (as opposed to Stereo or Mono). At the end, the processor mixes and outputs the voices through 32 channels, where groups of 8 channels have their own volume control.
- The Global Processor or 'GP': A programmable DSP used to process the audio data from the VP and apply various effects on it.
- Not all the channels coming from the VP have to be fed here, instead, specific groups can be sent to apply specific effects (i.e reverb) exclusively on them.
- The Encode Processor or 'EP': As the name indicates, it generates the final stereo signal coming from the GP and stores it in main RAM.
- Notice the operations of the EP can also be carried out by the GP, but having a separate component for encoding enables the console to strive for better audio encoding techniques, such as Dolby Digital.
The APU only processes audio data but can't output it. The latter is the job of the ACI, which reads the audio data in RAM, decodes it and sends the resulting PCM stereo sample (16-bit resolution with a sampling rate of 48 kHz) through the audio output.