You are purposely manipulating them, thats the point. Choose which you like the best and not what you are told you are supposed to like. Better that than letting your mind get manipulated by people giving you measurements and reviews lmao... Ask a con artist.
Full of contradictions, aren't you...
You say people shouldn't trust measurements, but marketing is credible source to get biased from?
If you trust no measurements, you should have even less trust in marketing of any product regardless of the brand!
I saw one he was reviewing the Hifiman Sundara's. Complains it is too harsh in the trebles and not accurate to original recording.
Web is indeed over the brink full of every kind claims... often from subjectivist.
But Sundara actually has more treble than many popular headphones like lots of Sennheisers.
(not that I would myself consider that as automatically bad thing)
As you don't trust measurements, what is saying that either of them is any more accurate than other?
If it's because you say so, that would be another contradiction.
Also that "original recording" thing is full of ambiguity.
Every sound reproduction system simply has its own inaccuracies/imperfections and hence that "original recording" isn't fully original coming out of it.
Or accuracy would have to be confirmed by objective no own opinions measuring instruments you dismiss.
Human brain simply isn't capable/hasn't evolved to accurately store (or even receive) sensory data, because there's no evolutionary use for absolute accuracy.
So instant comparison to real life acoustical thing would be closest thing for some kind semi accurate comparison.
As for mesurement results there can be certainly differences between them.
Already allowed distortion level has effect into power/voltage measurements results and would need specifying, like they are in precise documenting.
(btw speaker amps are measured/specified at lot higher distortion than headphone amps)
But we can be pretty certain that 1 Vrms into 32 ohms EPOS/Sennheiser hid under marketing is likely optimal for them value.
And used hardware is rather low end in capability and not even any mid range.
https://www.head-fi.org/threads/sennheiser-gsx-1000-1200-impressions.824923/page-30#post-13504383
Conexant CX20745 chip is literally meant as cheap solution for generic consumer electronics like phones, tablets and such:
https://prom-electric.ru/media/CX20745_ds.pdf
Datasheet also provides other info not told by marketing:
Charge pump for headphone amp's negative power rail has maximum output of -2.6V and design might well be using its minimum value -2V. (page 10)
That tells max headphone output voltage is meager and and nothing out of ordinary.
Hence advertising device as special headphone amp is misleading at best.
And already first page tells that D/A converter is quite low end one.
Both are something you would expect from below £50 entry level sound card.
