Allow Twitch Viewers personal volume control over Streamer's multiple audio outputs.
Whether it's music being streamed alongside a streamer's activities, or the depth of in-game volume you can hear over their mic. (I have no means of achieving the latter.) In regard to the former, let me give a shot at acting as if I know a little about programming...Would it be possible to allow the viewer to "modify" the volume slider located in the streamer's AutoDJ preferences @ nightbot.tv; through the means of a command in the viewer chat; i.e. !nightbot audio2 (value 0 - 100) ... a slider amongst the Twitch UI (above the current audio slider) would be preferable, but again, I have no insight to offer upon that digression...and I often get caught up in foreseeing the ability to personalize this feature custom to each viewer. Although, an ability to clone the coding needed for the slider @ nightbot.tv, then implementing that coding within the Twitch UI, as a secondary volume adjustment, would allow individual customization. Anyways, I'm speaking in circles, so I'll leave this as food for thought. I appreciate any and all consideration.
I do like 0x800CCC0F's suggestion. However ectofx, streamers should know how to set their audio levels accordingly. Ideally, Twitch should somehow enforce streamers to learn basics about audio levels and mixing... there are too many streamers that do not understand audio clipping, and have their voice level so high it clips (distorts), and game volume, background music is too low or too high. It is a delicate mix, and one I am quite familiar with... being a DJ. Audio clipping to me, is as bad as feedback or echo... you might as well be scratching a chalk board.
It would generally be nice if Twitch allowed streams with two audio streams along with the video stream, i.e. one for in-game audio and the streamer talking and one for the the music the streamer is playing in the background. Not only would this allow users to mix the audio on their side, for instance to listen to other music while watching the stream, but it would also be nice if a stream got its audio muted. In that case, only the music channel would be muted for copyright so people watching the VOD could still enjoy the streamer talking and the gameplay music.
If anyone can do something like this, itd be twitch. but maybe simplify it to just a 2nd slider in the UI, and allow the streamer the choice to include audio separately for the 2nd slider through obs or slobs and assign their choice of music source to that 2nd slider, allowing viewers to set volume independently as they please.