A few of the sounds that might be music to Toby's ears:
The jingling of car keys,
The crinkling sound of a plastic bag being opened,
The ring of his stainless steel bowl on the tile floor,
The clack of the leash snapping onto his collar,
The sound of the word "walk",
The chatter of a squirrel he chased up a tree,
The squeaker in a new toy.