Tyll is an honest man, and offered a spectacular service to the headphone community.
What he said about the HD600, HD800s, K812 and many other headphones are all solid opinions, and his theories are also of sound mind and reasoning.
There is definitely more harmonic distortion on the 800s, and it makes it a more “pleasing” “musical” sounding headphone than the OG 800, for many, except those who power the OG800 with a very harmonic tube amp lol
What many layman don’t understand is that NATURE is chock full of 2nd and 3rd order harmonic distortion…. So when we see a live concert, listen to speakers in any room which isn’t fully treated, or jam/practice with a band in any untreated space, that space is perpetually loaded with infinitely more 2nd & 3rd order harmonic distortion, than any incomplete acoustic design in headphones could ever generate.
So while there is VALUE to certain professionals to use tools with as close to zero harmonic distortion as possible (other than what we add deliberately with devices like Empirical Labs Full Analogue Tape Saturation Optimzer, etc)
There is also extreme VALUE to hobbyists looking for the most “pleasant”, “musical”, “natural”, “soulful”, “full” sound signature, so much that many use TUBE amps, which by their very nature add significant amounts of 2nd and 3rd order Harmonic distortion to whatever music signal they process.
It’s shocking to see some who spends thousands of dollars on tube amps and then speak negatively on harmonic distortion.
Harmonic distortion is exactly what they’re spending money on to avoid “clinical” “dry” “soulless” “unnatural” sound.
I blame the use of the word “distortion” in describing the harmonics. Since the very word “distortion” in lay vernacular has a connotation totally different than “harmony” lol