How music makes human happy, joyful, and exciting is a big puzzle. It’s suggested that a type of brain cells, astrocytes, can release a small molecule ATP upon pH change (Nature July 23, 2010), which associates with CO2 levels in the blood, therefore regulates the neuron respiratory center. It’s possible that music could, in part, impact on brain breathing, ATP levels, so sensation centers, therefore people are feeling excited, happy, or peaceful,  according to the types of music.