Watching it right now Rich. Interesting program indeed. I find the field of perception very interesting. The human ear "circuitry" is incredible.
I have been working on naturalness for the last 37 years. There has been some interesting findings, due to some interesting experiments I have performed, and am currently performing.
First, I think it would be good to remember, as shown in the program, that from live vocal to reproduction in one's home; that approximately half the electronics is on the recording side. From visitors, many forget this, or assume that the recording equipment is perfect.
Secondly, I have been working on what is required in one's system to produce natural "sound". This involves some interesting experiments.
This has led me into the rarified atmosphere of, well, I will let my experiments speak for themselves.
My initial experiment, years ago, involved using my 11A and its output adjustment "B" to compensate for different amplifier input impedances (Z). Being in parallel, I was able to adjust the FR in the bass region.
At more than one venue, we used a cello solo recording and I would adjust "B" until the home owner would notice a sonic difference. I was dumb founded to find the average FR deviation was some 32 udb (micro db) at 20hz. Of course the results will depend upon venue, components, resonances, and thus masking.
This led to more experimentation.
In another experiment, which I still perform, I adjust my test speaker zobel network resistance of 2 ohms by approximately .05 of an ohm increments. Clearly perceived.
Another adjustment of the speaker xover involves a 16 ohm resistor across the full range driver, with an approximately 9000 ohms (9K ohms) in parallel. Variations of the 9k resistor by less than 1 ohm are again clearly perceived.
An audiophile friend who visits fairly regularly, and I check and move the speakers by less than 1/16" increments, with side and front wall ceiling tiles by the same sensitivity. Actually, the side tiles are more sensitive to movement than the front tiles.
The conclusion I am finding that as we match more accurate individual components in one's system the reproduction becomes more natural. Matching two individual inaccurate components just does not produce as good of synergy as matching two individually more accurate components. I hope I explained that clearly.
As I stated earlier, I find the field of study very interesting. I am finding the human ear "circuitry" to be so incredibly sensitive.
Cheers
Steve