I'm wondering if this is a common phenomenon and if so how does it actually affect music:
When I play harmonic min2nd's the actual pitches I hear are not completely the individual pitches of the two notes but something in the middle. My ear averages the notes. The top note sounds slightly flat(probably around 10-20 cents) and the bottom note slightly sharp(probably less so). Of course, I do not hear the two pitches as if they were played melodically, there is inter modulation distortion going on which seems to act like the average of the two but I can force myself to hear the other pitches, but when I do so I always hear the top one a little flat (say I release the bottom note).
If this is a common phenomenon of the ears, which I believe it is although some individuals may be better trained or have better ears to distinguish min2nds and, of course, context matters (I'm assuming a synthetic piano), then how does this affect the harmonic aspects of theory? If one plays a closed voicing Cmaj7/B the C and B notes then, by this phenomenon, would produce sort of C|B(notation for note in between C and B) and this would throw off the entire harmonic expression of a Maj7 chord, out of context, at least, it would probably make the other notes sound sharp. Also, then it would affect voice leading and all that.
Maybe such things do actually go on in music and theory has not advanced enough to take them in to account? That is, in some sense we are actually dealing with something like 24-tet and harmonic m2nd's would be accessing notes in the extend divisions. It may not be 24-tet but whatever. The idea, though, is that it could dictate voice leading and resolutions. E.g., a closed Cmaj7/B would sound quite dissonant and suggest resolving probably to a G/B while a closed Cmaj7 would not have such a strong dissonance. Of course, then one would have to take into account the overtone series and compare any harmonic m2nd's as they too could inflect resolutions.
Trills seem to take advantage of this, typically trills on a m2nd are going to slightly alter the perceived pitch slightly below the principal tone (the subordinate tone pulls down the principal tone's pitch slightly allowing it to act sort of as a leading tone).
I've only heard this phenomenon talked about in one context in a book on blues where it suggested that this phenomenon existed and it was blues players trying to get at tones that 12-tet could not use. Guitar players would bend the notes microtonally to express them.
I'm not all that familiar with high note divisions of the octave which could possibly shine light on this besides being able to bend/slide notes on some stringed instruments. That is, has anyone explored higher order harmonic theory that can understand this phenomenon?