Sounds dreadful. Speak to him about it and if that's not an option get a supervisor on the case. I used to be in a workplace where someone sang all day, not a co-irker but someone who was around all the time. I kid you not. It wasn't loud, but everywhere she went she was singing. Why someone hadn't killed her by that point I don't know. Perhaps they have by now. I'm certain if she hasn't gotten over that by now it's hurt her professional career.

tape him and play it back to him on repeat.

Leave him an unsigned note . Gin

LOL! That's great! I really should just tape him!

Thanks....venting is great sometimes.