Musical and visual imagery are actually not coensurable through narrowly "representational" elements. If one speaks of genuine and profound relations and proportions between the music and picture, it can only be in reference to the relations between the 'fundamental movements' of the music and picture, I.e., compositional and structural elements, since the relations between the "pictures" and the "pictures" produced by the musical images, are usually so individual in perception and so lacking in concrete was that they cannot be fitted into any strictly methodological "regulations."
Eisenstein is very much a descriptivist except in regards to the "purity" of film form. Essentially , Eisenstein gets here at the spirit, the ethereal foundation whih must match picture to audio, not something which can be codified into a this equals that system. Sound and picture must organically be married, not systematically, by a subject who's spirit may, in hopes, be shared with his heater/viewer. Not sure how this applies to any of my essays, but it's an interesting quote.