How do I record audio from a USB mic and the audio from my computer? CC 2020

Okay, you haven't said, but this is for a PC: You couldn't set Audition up to do this directly - it would only record from a single source. There is a bit of software called Virtual Audio Cable which, if you set it up carefully, would probably allow this. But, and it's a very big but - it's phenomenally difficult to set up. This is a complex app deriving streams from inside your computer and re-routing them, so you need to know exactly what to do to set it up - this is not for the faint-hearted.

If you don't mind having both sides of the conversation on the same stereo file, then the easiest solution I know of is the app I used for recording direct streams - SoundTap.

SoundTap has an option in it that lets you mix your local mic source with the stream you are recording, but you have to be a bit careful with the levels. I don't have a USB mic, but I've tried it with a mic connected to a USB sound device, which is to all intents and purposes the same thing, and it works fine. I have no relationship at all with NCH software other than being a satisfied customer, incidentally.

Now I don't know much about Macs, but I do know that the way that they set up audio sources is to aggregate them into a single feed, and you select what you want. Whether this leads to an easier way to do what you want, I don't know - but somehow I doubt it, because your Skype feed still doesn't look like a 'source' as such. Maybe a Mac user would care to comment?

(P.S. - If I was attempting this on a Mac, I might be tempted by something like this: Skype Call Recorder )

(P.P.S - another app that has been recommended for Windows is Supertintin )