You can choose whatever impedance you want since you're going to have to isolate the analog signal from the digital usb in your solution anyway. Or the usb-c t

You can choose whatever impedance you want since you're going to have to isolate the analog signal from the digital usb in your solution anyway. Or the usb-c to 3.5mm adapter can have a matching circuit in it made up of cheap passive components. Not really a big issue. More importantly, is this an actual solution being pursued? It sounds good, but I can see this getting out of hand with each manufacturer having a different standard. Or there could be an "analog audio over usb-c" standard that codifies which pins get which channel.