I'm 15 weeks here and I'm already putting music on my belly. I listen to Phil Collins, Seal, and easy stuff like that. I think as long as your not playing Marilyn Manson or anything harsh like that you will be good.
I'm 11weeks & 3 days And I Started Putting Music To My Belly At 9weeks
Babys can not hear from out side the womb until 23 weeks
But can hear your voice from week 14, so you can start singing yourself :)