Wouldn't he need to take care not to create a scenario where it could be claimed he moved the ball? Also, as @Rulesman said he appears to be walking around someone's line (and possibly through line).
If I were asked to make the call I would say no penalty although I can understand why some think his delay was unreasonable.
If it's quiet enough that other groups aren't able to hear it unless they're really close, I don't have an issue with it, but it doesn't sound like that was the case for the OP.
Interestingly enough, if I heard someone blasting Journey in the middle of the fairway, I'd be totally fine with it.
You're right. I should have said that we keep the volume lower around them. Truth be told, it's not that loud to begin with. About what you'd have in your car. I can't hear it at all 50 yards away.
We ask as a courtesy, because there are those that need or prefer absolute silence in their game, and if they'd rather not play with us at all, they should have that option prior to teeing off.