"The Bells" is full of music. The bells ring out all kinds of tunes, and Poe uses musical language to describe them. In a way, the poem itself is almost a piece of music, since it plays with sound, repetition, and rhythm so much. It's no surprise that it's been set to music and even turned into a famous symphony (see our "Best of the Web" section to listen to some examples). Poe is using this poem, in part, to explore the connection between poetry and other kinds of art.
This poem is as much about sound as it is about meaning. Like the bells, the words of the poem evoke emotion through rhythm and sound as much as through ideas and content.
"The Bells" is a multifaceted work of art that breaks out of the standard limitations of poetry. Poe does his best to make the poem a visual, rhythmic, and sonic experience, without letting any one of those elements take over.