I can try giving you a tip: you say you're around music a lot. Sit on a subwoofer or beside a speaker with heavy bass. Do you feel it vibrating in your tummy (or anywhere else)? Take that vibration and go with it, empty your mind of rationalizations, and try to gain somekind of tactile "texture" out of the vibration. If you get there, go along with that texture and try to find patterns of shapes emerging from that texture.
I don't know if this would work, but it won't hurt to try, eh?
I have actually met a Japanese guy with a fascination just like yours. What he is doing about it is training for visualization (which is something that anyone can learn, synaesthete or not) by reproducing in his brain an accurate map of a huge landmark in Tokyo. He claims that visualization has helped him achieve synaesthetic states every now and then.