Music, for the speaker, is hard to put into ordinary words, so the poem opens by saying it is "something else." What follows is a single comparison: listening to music is like taking a bath in your emotions. The image is warm and private. Feelings aren't something to be analysed or held at arm's length here; you lie back in them and let them surround you.
The last lines push the idea further. Going underwater shuts out the everyday world, and the speaker hears "nothing but / Pure music / Pure you." Music and self blur together until they are almost the same thing. The music doesn't just entertain; it seems to reveal who you are underneath the noise.
The mood is calm, intimate and a little dreamy. The short lines and plain wording leave plenty of quiet around them, much like the muffled stillness the speaker describes. It feels like a small, honest confession about why music matters.