I agree, the science behind this topic is fascinating. 90% happening in the brain seems true for other sensory experiences as well: the same food can taste different, the same colours can feel different and so on. Just like those who appreciate great wine and willing to pay $500 or more for a bottle, on this forum gather the gourmet section of audiophiles. Understanding the biological and technical background is interesting, but we are here for the exquisite pleasure of enjoying good audio.Biologically and technically.
As Rob Watts mentioned from his story to evolve DAC designs, ears are 10% and the rest is our brains, these are capable to distinguish also small and tiny sound transients.
That could mean the more we listen to good gear, take it is an exercise, the more we can reveal in the sound joking. Though definitely the trained ears could distinguish more.
By eliminating barriers from signal in the DAC designs, and amps that is the base. Though it becomes soon tougher (i.e. distortion vs feedback) and that is why audiophile infidels say 0s are 0s and 1s are 1s, better not to know and be free.
On the other hand Great that we can hear the difference and great that the human brain loses memory so quick. We need keep listening to not forget
In my looking to understand why DACs and why cables sound not the same, having no possiblity to hear them all, I turned to synthesizers, the generators/composers of sound. A lot of truth and knowledge for audiophile to seek there. Recommended. Look to a square signal generators versus sinusoid ones and their harmonics when low pass cut-off. And then subtract one from the other. Unbelievable. That is what the ears could hear.
Now do some oscillations in amplitude, frequency, .. that is what impacts also our brain sensitivity.
Hint : if you cut off higher frequency then 20kHz as it is the top ears limit out of the square signal, it is no more square . Look to frequency spectrum of such cutoff square signal. Simply harmonics of various frequencies far beyond 20kHz are compounds of the square of 1kHz. All to do a ramp from 0 to 1. The proof that i.e. 1kHz square is not about 0s and 1s. There is more
I used to own a TT2 and Qutest, so I am quite familiar with Rob Watt's puritan design approach when it comes to DACs (and his DACs are indeed great), but many human brains prefer harmonic distortion to ultimate clarity. Just look why tube amps are so popular and how R2R DACs are on a rise these days.
Theory is important and interesting, but simply immersing into music via fine audio reproduction is even more appealing to me.