UPDATE: You need a virtual audio interface such as VoiceMeeter Banana or Wavelink software. Once you have that installed you can add input device as specific channels in OBS. From there follow steps from video!
THIS VIDEO SHOULD HELP!
• Separate Audio Channels for Your Stream in...
Playing music on Twitch without your VODs being muted or hit with copyright strikes is easy to do with Twitch VOD tracks in OBS.
Twitch VOD tracks are easy to set up and give you the ability to play music on your live stream but not on your Twitch VOD. Which will the other sounds from your stream to still be on your VOD, like your gameplay, mic audio, stream alerts, etc. This OBS trick is easy to do and shown in this video
Timestamps:
Intro: 0:00
OBS: 0:43
What are audio tracks: 0:57
Settings: 1:30
Ending: 1:55
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