What are we objectivists missing?

The current measurements were designed to measure instrument operational stability in an artificial normalized environment with artificial normalized signals.

So, the operation of the amplifier is measured in a Platonic setting (ideal dead resistor VS reactive live loudspeaker), and a single sine or square wave (eg THD) or a combination of two waves (eg, IMD), with the same signal cycling precisely over and over, at the same amplitude. This is also Platonic, as real music has very little prefecty repetitive elements, and most of the signal contains simultaneous extremes at both frequency and amplitude.

So, we are measuring a irrelevant signal (perfectly cyclic) with irrelevant load (inert resistor), so no wonder the results do not correlate with sound quality. They cannot - just as measuring a heart beat and bicep circumference will not indicate what a gymnast is capable on the floor!! They will not even indicate whether the subject is a gymnast or just a non-gymnast in good shape who can;t even do a flip....

They correlate extremely well though with whether the amplifier is operating as intended, or it’s time for repairs....

Interesting!

Thanks...

Food for thought....

Well, this did not go in the direction I had intended, but I suppose I should not be surprised.  I guess the take away for me is "We don't know what we don't know".

Thanks anyway.

Well, your question didn't make sense. 

My take is that if you can hear a difference, there must be some difference.  

Not necessarily, depends if bias has been accounted for. 

So what are your opinions on what those differences might be and what are we NOT measuring that would define those differences?

We can measure the audible spectrum for humans. We can even measure the spectrum for dogs and dolphins so I have no idea what your asking for. 

We can measure the audible spectrum for humans.

It is one parameter, this measure dont limit the complexities of perceived sound qualities in multidimensional neurophysiological analysis as such and by itself alone, but this measure limit only the physical range of our perceiving abilities on an external physical scale in decibel.......Sound is not only defined by decibels range...

Not necessarily, depends if bias has been accounted for.

here too you forgot the difference between the positive biases of a musician and confuse it with the negative buyer of an audio product..

Then if we can hear differences they can be expression of LEARNED biases then positive one, or delusion then negative biases... Acoustician and musician exhibit learned biases...

Thing are not always simplistic in two cases: true or wrong......

Blind test on musicians had demontrated their ability to beat the uncertainty principle in Fourier analysis ..

https://arstechnica.com/science/2013/02/human-hearing-beats-sounds-uncertainty-limit-makes-mp3s-sound-worse/

«This problem has been highlighted in a recent Physical Review Letter, in which researchers demonstrated the vast majority of humans can perceive certain aspects of sound far more accurately than allowed by a simple reading of the laws of physics. Given that many encoding algorithms start their compression with operations based on that simple physical understanding, the researchers believe it may be time to revisit audio compression.»