The sound quality between the Clear vs Elegia is quite significant. I wasn't prepared to go up to the Clear before the audition, but once I spend 2 hours swapping back and forth and listening to the same music I just couldn't let myself settle for the Elegia. I also listened to the HD800s, Audeze LCD-2, Shure SE846, Sony MDR-Z7M2 and a few more that I have forgotten about, before I went for the Clear.
Of course the Clear are open back and the Elegia is closed. But I find that the Clear aren't that loud from the 'outside' and the Elegia aren't completely silent outside either - they have designed a small port to allow air pressure to release, which contributed to their soundstage.
From my limited experience with audio gears (I'm a cheap skate and I don't constantly buy / sell gears) the source and the amp are usually easier to predict their sound but not with speakers / headphones. With source and amplifier as long as you do your research and knowing what you like, I find it is a game of more / less - with DACs unless it is badly designed / implemented you are picking components with more or less detail / soundstage width / depth. With amps it's more or less power / control over speakers and headphones (I agreed with those who say that a very good amp 'disappears' and gets out of the way). But speakers/ headphones have so many variables in their principles, driver type / design, crossover implementations, enclosures, even a grille / baffle affects the sound, you can't really 'get' what they sound like just by reading about their test measurements and reading other people's subjective opinion.
Personally I won't risk buying expensive headphones and speakers without listening to them. A lot of them. Now I totally get the difficulty with auditioning, especially now when we are living with the new 'normal' and the prevalence of online shopping. But if this is your first pair of expensive headphones, why not take your time and enjoy the journey by testing everything you can get your hands on?