Coleridge helps orient the reader by specifically mentioning music in a few places in "Kubla Khan." Even when he explicitly reference music, we think it's underscoring every line. Do you hear music in this poem? We definitely do, and we think he wanted his readers to as well. Whether the sound you hear is monks chanting in a cave, or the swelling of a symphony, we think music is all over this poem in the sounds it makes and in the way it moves.
Coleridge weaves music into this poem, both in the sound of the words and the themes he discusses. By doing this, he emphasizes the dream-like, magical qualities of the world of the poem.