My kitty just turned 19--yes, really!--and most of the time her hearing is OK. When it is, she is OK with most music. However, she is not crazy about the pennywhistle. When I used to have a clarinet student, she HATED that, & I mean a serious evil kitty I'm going to shred you into bits if you don't stop that kind of HATE! (her sister who is now with the Lord did not mind at all) Then I have a couple of pipe CD's which she does not like. When playing them, she will jump & run (for about 2 1/2 seconds--a marathon for her), & yowl at me & jump on me (whilst I'm in a chair or recliner) & stand on me, looking into my face--especially the CD with Uillean pipes & fiddle! I guess there's always a critic in every house.