Welcome Charlie:
In your preferred audio editing program, I'd start by giving it a good 30 db boost to both channels. It'll make some of the applause clip, but since it's applause, it's not a big deal. When you take a listen, you'll hear some noise in the recording which is caused by the hard drive on the jb3 when recording via the analog in. Anyways, take a listen, and then decide whether or not its worth persuing any further. You may want to try and compress the recording to even out the levels between the applause and the song intros and songs themself. You may want to try some noise reduction on the hard drive noises, or you may just want to leave it as is (what I would do FWIW) and go see Arlo again! Hope this helps. +t for your troubles...