The XA stream connector represents the flow of XA ADPCM audio from the CD-XA device to its associated amplifier-mixer (ampmix) device. During playback, the CD-XA device sends audio information from a CD-ROM/XA disc to the ampmix device for subsequent conversion into audio that can be heard through conventional speakers or headphones.
Although volume control is provided by the CD-XA device, the device actually uses the services provided by the ampmix device to modify the perceived volume level. If other advanced audio-shaping features are required, the application can retrieve the device ID of the ampmix device using the MCI_CONNECTION message. Once the device ID has been obtained, the application can send set commands directly to the ampmix device to manipulate audio attributes, such as treble, bass, balance, and so forth.