I've always been interested in how cats relate to music and sound. I've watched a few different cats react to music being played live or on recordings. I'm pretty sure they're uninterested in rhythms. And they seem to enjoy low, sonorous sounds. Higher pitched sounds are a mixed bag.
My old cat Eli used to enjoy my bass playing (even though I'm not very good). But he'd threaten to kill me if I ever played a harmonica. Most interestingly, when the singer in my old band came over to work on stuff, he hated it when we played sad songs. Didn't mind the punky stuff, but he'd howl at us if we played a ballad.
My old bass teacher had a couple of cats, and said that when he did tonality exercises on his upright—playing drones against a tone from a digital tuner, and slowly warbling in and out of tune—his girlfriend had to escape the apartment. But the cats would curl up on the floor right under the bass.