Cats have awesomely good hearing. While most humans top out at 15,000 hz, cats can detect sounds up to (and maybe beyond) 64,000 hz. That’s eleven octaves, one more than even a dog. It helps them hunt prey.
This got some scientists thinking “Well, if we’re going to make music for cats, then we should be sure to use their entire hearing spectrum!” The result is a special grand piano that, when played in its upper registers, can only be heard by felines.
To test it out, a pianist performed a series of songs for a row of cats. Selections included some national anthems along with Jay Z and the Backstreet Boys. According to video shot during the experiment, the cats really seemed to dig it.