lol, I'm not sure if they quite "hear" it as they most likely "feel" the vibrations on their little ear pockets. Whenever I play my Cello, Sora always stops next to it and looks up at me( I let her wander the house sometimes). At first she didn't seem to like it, cause she always ran away, so I didn't play when she was out, but after awhile, I guess she got used to it

.( she seems to like Bach the most

)