Hi All,
I have been experimenting with the recording on the audio channel. I recorded the a harmonica over the first chorus with great results. I then tried to record guitar strumming over the second chorus and ran in to a major problem:

1. The audio input from the guitar seemed good on the VU meters, but when I listened to the overdubbed audio channel I found the audio level quite low when compared to the level of the output for the harmonica.
2. I thought I might try the guitar direct input on the interface but I couldn't find a way to select this input for recording. I noticed that the VU meters were responding well to the guitar and thought it might be selecting from both channels, but definitely not.

Microphone - Shure SM57
Audio interface - Focusrite Scarlett Solo


Any ideas please?