It's a noisy and cluttered head over here, so internal noise and to some lesser extent the ambient soundfield.
I rarely play music through the radio or turntable these days.
Sometimes a song will surface, similar to a moment in a (late) Tom Deitz novel, which might be synchronistic commentary, or merely a reaction to some shared elements coming into play.
Sometimes it's just the sound of my own voice forming phrases and longer utterances before I type them, but sometimes I recognize that I might be some damaged wayward battlebot of verbiage, or futile offerings.