In this TouchDesigner tutorial we route audio from a media player (Spotify, YouTube, iTunes etc.) into TouchDesigner using the freeware VBCable. We also create a custom component so you can reuse this in the future and we create a simple visualisation to get you started. You can also use the Stereo Mix on Windows if that's available for you. This technique should work on both Windows and Mac. Download VBCable: https://vb-audio.com/Cable/