cpsmusic said:
In it the author says the following: "I found that some of the channels will have an almost identical frequency response and harmonic distortion levels but their phase will be different at certain frequencies. "
Phase is a very common BS argument. A console's signal path is a minimum-phase system, where the phase and frequency response are intimately and bi-univocally correlated. In simpler words, a phase difference always translate as frequency response difference and conversely.
What's more, the hearing process is not very sensitive to phase
per se, but quite sensitive to frequency response.
However, it is sensitive to the difference in information arrival time, so, yes, possible phase differences will be heard as a displacement of the source.
But it would occur only with significant differences in frequency response.
Actually, what can happen in a mixer is multiple paths; let's say a signal is routed direct to the main bus and simultaneaously to a sub-group that is also routed to the main bus. This is not anymore a minimum-phase path! It ispossible that the relationship between phase and frequency response becomes more complex. In a "modern" mixer, it should not result in audible artefacts, because it would happen at ultrasonic frequencies.
In less "modern" mixers, because of transformers, these artefacts fall within the hearing range.
Vintage Neve mixers, that include several xfmrs in the signal path, are notable for these effects.
It was one of the first things Allan Archer (Neve tech) warned me of when I worked on the Barclay Studio A646.
I think this difference is what I'm hearing in my hardware 1073 clone that isn't present in the plug-in.
If you have a notable difference between two 1073, it should be measurable as a different frequency response.