[He grins over at her before casting his attention back to Sound Machine, frowning slightly in thought]

Not that I know exactly what I'm looking for [he can admit that, she's definitely got the edge here and he's ok with letting her know he knows it, but he's not Batman's protege for nothing, so he's at least going to make a guess] but there's something odd about his guitar, I just don't know if it's odd enough to be what you're looking for.