I usually "listen" to songs in my head while relaxing or even PR'ing sometimes. I discovered I could do this back in 1990. I had just moved to live with my dad, and we were moving into a larger house about 40 minutes away. Dad was driving the U-Haul truck (LOUD truck). I was thinking about a song I liked, and was surprised that after thinking about it for a while, I could "hear" it in my mind. One repetitive "song" that ALWAYS works to relax me is the 5-Note sequence from "Close Encounters of the 3rd Kind". The part where the residents in Dharmsala were chanting the notes. For some reason, that part has always worked to quiet my mind.
I use this sometimes in place of the "re-lax chant. It can usually only "hear" the music/songs in the presence of some sort of backgroud "noise". I hypothesize it has something to do with the "noise" in the background stimulating the auditory portions of the brain, and perhaps these need to be "turned on" for the music to work (for me anyway).
I would think as long as it is music that you could use to stay relaxed and detached, it shouldn't matter.
Bill
