what if you hear the blues in all types of music? what if you hear mellow yellow in all types of music?
and what would the natural or man made world and sounds sound like?
Reviews colored-hearing synesthesia, in which sounds induce visual images (photisms).
Colored hearing manifests correlations between dimensions of auditory and visual experience. Two general findings are that (a) the brightness of photisms varies with the brightness (density) of the inducing sounds and (b) the size of photisms varies with the size (volume) of the inducing sounds.
In colored hearing produced by speech sounds, the induced hues and brightnesses can be related to the formant structures of the vowels. Synesthetes align dimensions on different modalities in ways that are qualitatively similar to the ways that nonsynesthetes align them (e.g., in phonetic symbolism).
Synesthesia appears to be a cross-modal manifestation of connotative meaning in a pure sensory form; its inflexibility (compared to language) makes synesthesia less significant in adulthood than in childhood.
On colored-hearing synesthesia: Cross-modal translations of sensory dimensions
what colour would be the sound of music? what colour would be the sound of your music?