Sounds (pun intended ;-)) intriguing. Is a specific visually perception related to specific sound, e.g. like the classic example of a musical note evoking the perception of a specific colour?
On a slightly related note, being colour blind Neil Harbisson - the world's first legally recognized cyborg - had an antenna implanted in his skull that allows him to perceive colours as sounds (musical notes and even chords, specifically); so, the inverse route in a way.
Specific types of sounds result in the same types of shapes and colors and unexpected sounds particularly when my eyes are closed produce the strongest illusions. There are some color/sound overlaps I can only "see" when my eyes are closed however an unexpected dog bark will result in an effect I perceive in full day light.
The related shapes I "see" are also based on the sound I hear.
For example, a vaccum or motor gives me gentle waves or pulses of blue that start low in my "vision" while that surprise dog bark will be a bright white explosion usually in the top right of my "vision"
On a slightly related note, being colour blind Neil Harbisson - the world's first legally recognized cyborg - had an antenna implanted in his skull that allows him to perceive colours as sounds (musical notes and even chords, specifically); so, the inverse route in a way.