Music isn't always music, when you're in the middle of making it. It can easily be a mingling of senses - something felt, seen, tasted or remembered - and converted to sound, just as Louis said.
I can vouch that when the Muse is in, and the sound has a life of its own, I am NOT thinking about anything technical to do with music, such as what key, what chord voicing, and so on. I could be trying on dark green, or tasting sweet potato, or remembering someone. The musical result probably won't evoke the same stuff in the listener, but she'll catch on that something is happening, and that it's more than just noises emitted from an instrument.
Of course, Louis Armstrong was far galaxies beyond mere technique, and could express in music anything he imagined or sensed.
My favorite kind of music happens when the artist reveals worlds, and makes me forget the specific instrument he's playing, or style he's doing. Bix is the March poster boy for this, and there are many others. I love it especially when someone does that using the humblest of instruments (washboard, kazoo, harmonica, banjo, etc.).