Z1R vs Mest MK2 (and with some MK1 and Monarch)
Source - Anedio D1 desktop DAC/amp (also tested with ifi Micro Black Label)
OK, my impressions about the Sonys are a bit strong so I met with another kind Head-fier in my area and we did some listening together with his mk1 as well. We have some differences in opinion which I'll mention, but it's not my place to say what he thought. However, I'll caution some of my impressions in that some people might disagree.
Treble
Z1R - Z1R treble is loud. Depending on how treble sensitive you are, I think some might characterize it as "extended," but I am a bit more on the treble sensitive side and to me it's loud. I found the treble unresolving and sibilant when compared to the Mest Mk2. It's like a blur of harsh treble that doesn't separate out the tones very well. Different cymbals played at the same time get mushed into a loud treble sound. I tried to tone down the treble with EQ which helped it a bit but it's still unresolving in that there's still no coherent separation. There is also sibilance. It took me awhile to find it and it's around 3-4k. The other Head-fier also found the Sonys treble to be harsher than the mk2, but he also found it to be more detailed than the mk2, so YMMV.
Monarchs - The Monarchs treble is also a bit loud for me. I had to tone down the upper-mids to treble region with EQ about 2 db.
Mk1 - The mk1 has sharper treble than the mk2 which makes it sound more expansive. However, when the mk1 and mk2 are EQ'd to my preferences, they sound almost identical.
The mk2 has toned down treble compared to the Monarchs and Z1R, but its more resolving and not sibilant. It's very airy and effortless. Cymbals and high tones are well separated.
Mids
Z1R - Mids are sunk and unresolving compared to the Mest mk2. The upper mids of the Mest mk2 is almost perfect for me in terms of volume. The Z1R mids just sound wrong. The sound signature is V shaped. Very commercial sound signature to me. The mids are not only sunk, but also blurred. Imaging/separation between tracks is inferior to the mk2. The bass also bleeds into the mids.
Monarchs - The Monarch's upper mids to me were too loud. The Monarchs upper mids are more forward than the mk2 which to me is great for the first 10 minutes or so, but after an hour, I find it unbearable. The mk2 is much better to me in this aspect.
Mk1 - The mk1 has a bit sunk mids, similar to what you hear from a Sennheiser HD800 from what I remember. Again, once I EQ'd the mk1, it sounds almost identical to the mk2.
Mk2 has very natural, accurate, and coherent midrange presentation while also being very resolving. Extremely good track separation in guitars and vocals.
Bass
Z1R - The bass is strongest attribute, but it is like you listened to a rock band live and it is the bass guitar that overwhelms the rest of the band. On the mk2, you still hear the bass guitar, but it's behind the guitars. To me, that's how a band actually sounds as I was in a rock band in college. I don't think it is accurate to have the bass guitar as the star of the show when they are normally in the back as rhythm. The subbass has great rumble and detail. However, it is not too different than if I bumped up the mk2's subbass with EQ about 3 DB.
Monarchs - The subbass is less detailed than the rest, but it had pretty great impact which made music fun to listen to. I don't remember the Monarchs enough to know if the impact is similar to the Z1Rs are not.
Mk1 - Has more emphasized subbass than the Mk2. I found mk2 and mk1 can sound very similar here with EQ as well.
Mk2 - Has great texture in the bass. Has a bit less impact than I would like. EQ remedies it somewhat with around a 3db boost.
Soundstage
Soundstage of the mk2 and z1r is pretty much identical. Both would be superior to the Monarch in this regard. Mk1 has wider soundstage, but the treble gets fatiguing. When you EQ the mk1's treble down, the soundstage is then similar to mk2. Maybe still a bit wider? I don't know. It would be nitpicking.
Imaging/Separation
In imaging/separation, the mk2 is superior to the z1r. The Z1r imaging is very good, but I'm not sure if anything could beat the mk2 here. I probably won't believe it's possible to beat the mk2 in imaging unless I personally hear something that does. The mk2 is just so resolving and tracks are so well separated without having a bass deficient tonality like an HD800. I don't know where the Monarch would stand in terms of imaging vs the Sony, but the mk2 is a bit better.
To me the Z1R is excellent for Hans Zimmer tracks. Basically music that is expansive and bassy. For everything else, pop, rock, acoustic, vocals, I prefer the mk2.
As for the mk1, I almost felt it was just a tuning difference, but I didn't get a long-term listen.
Conclusion - I really like the mk2 and I couldn't live with the tuning of the Z1R. The other Head-fier was nice enough to do a trade with me so I should have the pleasure of hearing the 64Audio U12t soon.