I know the m12 module was originally shipped with the U4s, not just from reading, but also because I owned them. I did not imply that the m12 module was specifically made for the Volur. Just to clear that up.
Yes the Volur is advertised as being inspired by an evolution of the Nio. Your mistake is considering it the Nio2. Every other review of the Volur generally uses the m15 module, the one it ships with installed, you are the only reviewer who went with the m20 as the ‘intended’ sound. Again the majority isn’t always right, but in this case, the majority is correct. To me, the usage of the m20 module as where you drew your sound impressions from, was a mistake.
I completely disagree the Volur is marketed as a basshead IEM. FatFreq IEM’s are, and some Empire Ears, and one can argue that the Nio was definitely marketed for some people who call themselves bassheads, as the marketing literally mentioned for bass players and drummers. But certainly not the Volur. And pretty much every other review notes this - this is just really good present bass, some of the best quality bass you can get, but not really what most of us consider ‘basshead’ levels.
The Volur is advertised as super high quality bass. In the head-fi community we differentiate between basshead bass, and just really high quality and present bass. FatFreq are advertising to bassheads, the Volur is not. Having excellently textured and quality bass, which is what the Volur is advertised with, is certainly not basshead marketing. I think this might be your biggest mis-step here.
I never said you should have reviewed the Volur with just the m12 module, and in fact said multiple times it should be reviewed with the m15 which it came with installed. But the mX and m20 modules are both generally seen as the extremes of the four modules - the m20 generally providing bass leaning towards basshead levels, and the mx trying to ‘neuter’ the good bass characteristics. I still stand by reviewing these with the m20 module as your primary focus for sound impressions, unlike any other major review, was just an honest mistake.
I do know treble can be a point of contention and I am not saying to not point it out that it bothered you. But the way you did I felt was unfair. You said you can hear treble up to Xkhz and then said it was too much. But that is simply not the case. Just because one can hear treble up to Xkhz means nothing, UNLESS you are sensitive to it. There was another review of the Volur where that was mentioned, but they kind of clarified it with their subjective experience with treble. Also, while yes, some people have said they are sensitive to the upper treble in the Volur, it is definitely a minority compared to those who say they aren’t - at least from the many hours of reading I have spent on 64Audio IEM’s especially the Volur recently. It was the way you said it, not that you pointed it out that is where I took issue.