From the DVD commentary, episode 1:
Neil: The music in the background is still Schubert's Quintet [that played when we first saw Aziraphale in the bookshop]-
Douglas: -and it's playing on Aziraphale's old gramophone, but because they're drunk we've distorted the sound to make it sound drunk as well.
Neil: So it's speeding up and slowing down...
Douglas: ...and distorting.















