We are left to imagine what the composer had "in mind" when writing down compositions, for there is no way to know what sounds were swimming around in his/her imagination.
For example: I cannot help but notice, now that there is a natural horn in residence in my family, that Mozart refers to horn sounds in keys most commonly identified with that instrument, notably F and B-flat. So there was a specific sense of this tonality as opposed to that--among the things that get "trained out of us," as an eminent theorist described it to me.
Tonal Refraction, my method of equating the fleeting aspects of tone perception with colors, enables the individual to restore some of the specificity of pitch that gets lost in the process of theoretical equal-temperament, in which we learn function rather than character; in which every major scale is like every other major scale; in which a tonic chord in root position is a tonic chord in root position.
We cannot re-enter the composer's world, try as we might, and there is no doubt but that period instruments have helped illumine the difference between present-day sound and the sounds of the 18th century. But we can re-enter our own lost world of first encounters with tonal essence.
