What is your setup?

If the source(s) that you want to listen to are Firestick or similar HDMI output device and they are correctly connected to the 976 as inputs you should not need to have your TV powered-on to them as outputs when listening to music.

If the streaming device is attached to you TV and you wish to use the Audio Return Channel capability of the HDMI Output #1 to have the audio processed by the 976 you must have the TV on.

These options are explained on pages 17-20.

You should also review the settings for CEC and "assign video & audio input" on page 25 & 26.