I think it would be great to have an in-game audio channel with each player having the option to mute/un-mute their mic and speaker to that channel. Spectators would have the ability to listen to the chat but not speak (no mic). Players should be able to mute their mic from the spectators speaker (only heard by individuals in the game). There should be a visual of who is using the voice channel for both the mic and speaker. Maybe mic and speaker icons that show up on either side of the player logo, and an ear next to the eye balls to indicate when the spectators are listening.