Ashermusic
Senior Member
As i've already mentioned in some other threads, one aspect that strongly influences our perception of orchestral music is the fact that in real orchestras lots of inacuracy is going on, specially in the area of intonation and rhythm. (Allthough it is to mention that both aspects improved miles over the last decades).
And one crucial aspect occurs when it comes to the intonation of octaves.
Why?
If a perfect octave is played - perfectly synced with the same vibrato (or without any vibrato) - the brain tries to identify the octave as a single sound (where the higher octave is partial 2).
That's the way additive synthesis works or its predecessor: the organ.
Sometimes this constellation is no problem, because this effect is desired.
But sometimes, when samples are perfectly tuned, constellations may occur where suddenly some kind of weird organ sound emerges out of the orchestra.
Fast string runs or brass textures in octaves are usual culprits.
And indeed, my ear really dislikes that specific sound.
I've analysed the intonation in lots of (great) real life performances and came to the conclusion that in some textures quite brutal inaccuracies in the area of intonation are well perceived by the ear (unfortunately it's quite difficult to make generalised suggestions; but there are e.g. fast runs in octaves where a difference of about 30 [!] cents between some notes still seems acceptable to the ear).
So, one very rational argument why mockups sometimes sound "terrible" is the fact that some of these exact octaves create the impression of Meta-organs that pop up and vanish.
And that's simple not sexy to the ears.
BTW in the same regard it seems to be no coincidence that Strawinsky insisted on "non divisi" in the strings in the famous chord in the Sacre ("Les augures printaniers: danses des adolescentes" [13]), since played as double stops, there is much more roughness in the overall intonation.
Sometimes small amounts of dirt are eligible.
Well stated and I think it can be distilled to a simple equation. Good but imperfect=human. Perfect=machine.