Puritan Board Graduate
How is listening to an atheist sing or play guitar sinful?
I think the point would be that you would be allowing them to deliver a message to you. The question then would be: is it a good thing for me to have this message as part of my regular 'diet'?
Edit: Of course, it is much easier to identify a problem if there are lyrics to analyse. If it is a piece of music that has no lyrics, then the question would be whether this piece of music influences me to have ungodly feelings. Personally, I know that there is music that I could listen to that if I were to have a disagreement with someone soon after, I would be much more likely to act in an ungodly manner.