User blog comment:Psypher/Young Justice Soundtrack out July 16th. Pre-order now./@comment-5037384-20130524190657/@comment-5188108-20130525140434

Jason had another role.

There's been one or two times where some nameless background character has said something brief and I wondered if it might be Jesse, but none I could put my finger on. I suspect the reason he never sang anything is that they might need his record label's permission to do so. That or they didn't want a recognisable voice.