On the topic of easy listening, I think this is an area where the Z1R will be very divisive. I suspect it all depends on whether the two big peaks in the tuning, the 3 KHz peak and the 10 KHz peak, are bothersome to the listener. The 10K peak is something that Tyll at InnerFidelity couldn't get over. His negative review of the Z1R is why I ignored this headphone for so long (I read it when I was an audio newbie and hadn't learned to not base my decisions just on one reviewer). Looking back at it, the vast majority of what he didn't like about the headphone was that peak. Now, I can hear that peak as well as the 3K peak, but they don't bother me most of the time. The 10K peak can sometimes add unwanted sharpness to cymbals and certain vocals in modern music and can introduce this "whistling" sound in the background, but I don't find it uncomfortable to listen to. Likewise, with the 3K peak, they can make some vocals scratchy sounding at times, but they also add a desirable presence to them.
If the big peaks don't bother you, then the Z1R is quite easy to listen to. There's lots of bass to add heft and body to the sound and the normal sibilance range between 5K and 9K is quite recessed, so vocals are rarely sibilant except when they heavily token 10KHz. Vocals are imaged further away, so they aren't too forward or shouty and that adds to the relaxed character of the headphone. I find the Z1R quite good for relaxed listening in most cases. I don't listen that loudly, so the equal loudness contours of lower levels naturally mitigate the effects of the 10K peak, while the bassiness works in my favor at those same levels.
I've found the peaks also quite difficult to EQ out without also losing the easy listening traits of the Z1R. Since the mid-treble is so recessed other than those peaks, if you just EQ out those peaks, the sound becomes muddy and lacking detail and spark. So the "simple fix" of narrow-band EQ to chop off those peaks doesn't actually improve the sound as a whole; you eliminate the discomfort but eliminate detail in the process. You'd have to boost the sibilance region between 4K and 9K to compensate for the reduced peaks, but then you've lost the spatial positioning and character of vocals and strings. Vocals come to the front and strings cut through the mix. It sounds like the usual clarity-emphasized or neutral tuning, and the easy-listening qualities of the Z1R are lost.
To me, it seems that those peaks are quite strategically placed. If you want a generally recessed treble (for greater forward vocal distance and easy listening qualities), then you lose some detail in the process. To give that spatial distance between soloists and background vocals (at least in orchestral works), you need a specific peak in the upper midrange to give some vocals more presence without moving all of them forward. That's the 3KHz peak, right in the middle of the ear gain region. To avoid the upper treble sounding dull and lacking detail, there needs to be a peak there somewhere to retain that relaxed character while also providing enough perceived detail. That calls for a peak, but where? If it was lower, like 8 KHz or 6 KHz, then it would fall in the heart of the sibilance range, which can make many instruments and vocals stabby, sibilant, or tinny like on some Beyerdynamic DT models or the HD800S. If it was higher, like above 12 KHz, it can result in an overly sparkly and airy sound like some Hifiman or Audio Technica models. So by putting it at 10 KHz, it makes cymbals more prominent and gives that sense of detail and emphasis without losing the overall relaxed treble character. It's quite clever, but there is also the risk that those peaks sound too sharp for some music or for some people. Fortunately, the risk paid off for me.
