Surely it is a subjective opinion. I have owned several pairs of ESL57, Audiostatics and listened several times to Acoustats , not the STAX. Staying close to "the device gets closer to what we imagine happened at the live (studio or concert) event." for me the ESL63 could show more resolution, detail and more inside the whole music than the others.
Again IMO I found the others either more limited or not so balanced (favoring some aspects and ignoring others) as the ESL63. For some reason ESL63 were (are?) used by some professionals as monitors for classical music.
Again my subjective opinion, the only speaker with full range and scale I had in my room that could rival them was the Wilson Audio XLF. Soundlab's are great speakers, but for the purpose of our subject are colored - there are no miracles when you drive an almost two square meter film full range. BTW, for me transparency also addresses space.
I'd be very curious to hear what you think of the new Popori ESLs, which are both very full range and also easy to drive- so far of any of the panel speakers I've seen, by far the easiest to drive with sensitivities at 1 meter of 96dB. Benign impedance curve too.
I never thought artificial distortions enhance resolution. Whether or not something sounds natural is the key question here.
I think I've mentioned this a few times, on this thread as well as on your system (Natural Sound) thread. The 2nd and 3rd harmonics do seem to be able to bring out certain details including enhancing perception of the soundstage, depending on phase and amplitude of the harmonics.
For example if the 3rd harmonic is in phase with the fundamental tone it will make that tone seem louder. This fact has big implications on our perception of how different amps sound different!
Then how come some amps that are low power and have high distortion on peaks sound more dynamic, and low distortion high power often sound quieter?
Some lower power amps (like SETs without feedback) do this because higher ordered harmonics, used by the ear to sense sound pressure, show up on leading edge transients where more power is required, thus causing the amp to have a false sense of 'dynamics'. I've said it many times that in audiophile conversations you can often exchange the word 'dynamics' for 'distortion' without changing the meaning of the conversation.
SETs have so much distortion that its hard to tell when they are clipping. But even at low levels their distortion is so apparent (and frankly, embarrassing) its easily heard. If you understand how the ear can distinguish between a country fiddle and a Stradivarius then you'll understand how profoundly any zero feedback SET is modifying the signal.
IMO - some people will surely disagree - is that currently the real challenge to an amplifier are top high quality digital recordings , that are more transparent and dynamic than vinyl. BTW, there is a technical reason for it - as digital can carry more information than vinyl , sound engineers use less tricks to please the listener, depending more on the true reproduction of microdetails to enjoy listeners.
Surely some people can prefer to stay forever in the "golden age" considering that is was the best of stereo - it is an hobby of preference. IMO, YMMV.
As a mastering engineer I have to challenge this. These days most digital releases have compression as there is an expectation they will be played in a car. For the LP there is no such expectation and so if the producer is up on his game, will supply the mastering engineer with an uncompressed master file (or in rare occasions, tape). LPs have considerably more dynamic range than most people have any idea, owing to the noise floor mostly occuring in the pressing plant. Acoustic Sounds, with their mechanically damped pressing machines in their QRP plant, has improved the noise floor by 15 to 20 dB, putting them within6-10dB of 16bit.
FWIW I never encountered a single project that required any 'tricks to please the listener'. Usually its figuring out how the engineer the cut so it will play on a run of the mill record player. If you spend time with the project even out of phase bass can be conquered. But mastering LPs costa more than expensive lawyers and that right there is why all the 'tricks' get used.
Hardly anyone actually uses 16 bits (96dB noise floor) of digital as compression is so common. In addition, any modern LP has bandwidth to 40KHz. I've cut and played back 30KHz signals in the leadout grooves by the label, so that old hack about less information as you get near the label is a myth insofar as 20-20KHz is concerned.
Finally, with 30dB of feedback typically wrapped around the cutter head and mastering amps (which have feedback of their own) the actual distortion on the LP is
vanishingly low. Ask Bruno Putzeys what 30dB of feedback does and you'll see. 95% of more of the "distortion of the LP" occurs in playback. Topic for a different thread...