There're two audio output solutions with IFP7550.

1. COAX OUT: 

    When connected a coaxial cable from COAX OUT to an external amplifier, the output signal level is fixed. 

    With this connection, both integrated and external speakers will sound at the same time.

    Users can control volume of integrated speakers by remote controller or control buttons and external speaker by amplifier.

2. AUDIO OUT: 

    When an audio cable is connected between AUDIO OUT and external amplifier/speakers, the integrated speaker is on Mute. 

    Only volume from external speakers can be adjusted by amplifier.