Mini shootout I did between the IER Z1R and 64 Audio Nio
Of the 3, based on my impressions, the Nio and Z1R are the clear favorites. The Z1R is really impressing me on this second round (I owned one for about a month a couple summers ago). Holy Mary Mother of Balls does Z1R's bass sound good through the M8. Shanling's stated intent to provide a signature as smooth, powerful and alluring as carved jade is really coming to fruition here...Z1R + M8 is possibly the nicest standalone bass I've heard in a portable setup. Any fears that the M8 and Z1R wouldn't compliment each other well are entirely unfounded to my ears. Could the Z1R be the more v-shaped compliment to Ely I'm seeking...time will tell. The treble on the Z1R is also really nice though having gotten used to Elysium's treble it's not quite as impressive as it was the first time I heard it. The Z1R's treble can be a touch metallic at times and I often wonder if DD treble has a tendency towards this because all the times I've really noticed it have been in DD IEMs. The treble on the VE Elysium has pretty much entirely converted me to the school of e-stat treble...it's detail, speed, clarity and if done well lack of harshness and bite...is unbeatable.
I've got a newfound love and respect for the Z1R right now. It helps that the longer stemmed Sedna tips (that I didn't have before) seem to be entirely mitigating any fit issues I had when I owned it. Further, my source at the time of owning Z1R was the n6ii + A01-- that particular board tended to bump the mid-bass slghtly and that may have exaggerated the slightly veiled mids on Z1R. I still notice this to some extent but it's not bothering me as much now.
Really liking the bass on the Nio...it's a bit more technical/detailed than I was expecting on the whole and altogether it's a fun and engaging listen. That said if I were to own one I'd probably EQ down 2 and 4K by a couple DB each.
The M9 has failed to connect with me so far, but I will try again. Initial impressions are that the M9 is like a u12t with thicker bass and a dash more personality-- though neither the u12t or M9 IEMs seem like they will take down Andro and VE8 as my favorite BA IEMs.
Mini shootout:
**+Nio =>** Decent Mid-range presence and instrumental timbre, vocals nicely placed in the mix, great balance, decently detailed, layered and technical, impactful slightly elevated controlled bass.
**-Nio =>** Not quite as technical (layering, staging, imaging etc.) as some other hybrids I've heard (Z1R, Solaris, Legend X, MEST), can be a little shouty in the 3-5K region at times though this can be remedied for the most part with EQ, mid range is nicely detailed but too thin for my tastes on the whole.
**+Z1R =>** Peerless bass texture & extension, which the M8 absolutely milks for everything it's worth (seriously this is a heavenly pairing), fantastic staging and technicalities, great mid-range texture, if a little too tucked behind a veil of bass at times (though admittedly this is nowhere near as noticable on my M8 as it was on my n6ii+a01), a really fun and engaging sound overall.
**-Z1R =>** A little too v-shaped for me to be my only IEM (ie., as with the MEST often I find myself zoning out on the amazing bass whereas in my ideal setup my attention is drawn to the whole of the sound), highs can be a touch metallic-- though I wouldn't go so far as to say "harsh--" at times. Definitely tends towards "Chi-fi" tuning (upper mid/lower treble/sub-bass emphasis over mid-bass and lower mids).
**In summary:** My overall preference is for a balanced, open, natural and accessible midrange-- which is why I tend to gravitate primarily to "bass lite" IEMs like Elysium, Solaris SE and Andro. If I had to pick one of the Z1R, Nio or M9 to be my only IEM it would be the Nio due to its more balanced and accessible mid-range. The Z1R is shaping up to be my ideal choice as a secondary more "fun sounding" IEM to complement Ely. I didn't mention the M9 as much as I've only had a bit of time with it and haven't really connected with it-- it honestly sounds like someone took an Andro 2020, thickened the bass and sucked the heart and soul out of the sound.