Next time you are relaxing, put on some of your favorite music. Lean back. Close your eyes.
Start with your ears. Listen to the rhythm, focus on what you really, really like about the sound, the voice, instrument, beat.
Now think about the Color of the music. The wave of hues that make the sound come alive in your head.
If you allow yourself to view the color of sound, you will be surprised.
No, this isn't a flashback.