Colors and shapes... what else could fit in this?
How about taste or smell.
Some of the combinations of composers you associate wityh the same colour I find interestingly odd. Bethoven/Schumann? Alkan/Brahms? Mozart/Schubert?If I were to associate them with anything else, it would be food. But then maybe that's because it's nearly lunchtime and I'm hungry.
Scriabin = worms, dirt, fish in the Mariana trench, mud, decaying animals