You're right that VTF must be absolutely spot-on before you can truly optimize VTA/SRA. Doing that by ear requires listening for:
a) the integration or timing of fundamentals vs. harmonics (what Frank Schroeder and I hear) or,
b) the quickest rise/fall times and greatest amplitudes of individual notes, especially bass notes (what Paul hears).
One of my New Year's resolutions may be to wonder less if I'm a few angels shy of a pin full and wonder more at the music itself. Those might not be mutually exclusive activities, but its not New Years yet.
So maybe Doug and others can elaborate on what/how one listens when making small changes. Sometimes the vocabulary we use strikes me as chunkier than the product of the fine grained adjustments it attempts to describe. I'm fascinated as much by the assessment part of the process as the analytics and rationales.
From the above, I interpret 'a)' (integration of fundamental and harmonics) as the absence or lessening of what I call tonal 'smearing'. To me this is as much a temporal issue as it is anything, but I'd love for anyone to elaborate further. Several hundred messages ago in this thread we mentioned the piccolo solo in the third movement of Tchaikovski's 4th - many notes in a short span of time. When the leading edges bump into the trailing edges, such that notes are less tonally individuated, I call this 'smearing'. A smeared single note is slightly 'de-focused' tonally, it is less 'compact' as if its harmonics slather outside proper temporal boundaries. Correlating back to reality, better 'tonal focus' means homing in on the setup sweet spot. Is this at all close to what you're talking about??
Wrt to 'b)', I think I grasp listening for amplitude, but help me out with listening for 'quickest rise/fall time'. More words (heh) or an example? Without knowing better, I'd think this was ultimately the same thing as 'a)' put differently, but that could just mean I'm confused.
Apologies if my phenomenological bent goes against the grain of the thread - just more universal struggle for understanding what is sometimes tough to put into words. Betwixt the turn of the dial, the tenth of the degree, and the ear is where I'm working. How, or to what, do you listen for the effect of the changes you're making?
Ho, ho, ho,
Tim