RN6 has brighter treble in the mid treble. It’s peakier which also gives it more grit and attack, more of a metallic timbre whereas CP622B is slightly brighter in the defintion/ brilliance range, but it’s softer on the ears.
RN6 has a more engaging and bitey treblr, amazing for rock and more dynamic bits, but maybe best in a shorter rocking out session.
CP622B has the engagement to be considered TOTL in dynamics, but it’s certainly not its speciality. It’s a very delicate dance between dynamic (incisive) and ethereal (rippled overtones) treble. It‘s fantastically refined, and makes it a generalist for any music you throw at it.
Ironically, Anni23 and Mentor, though they really are different indeed to my ears, do sound relatively similar if playback is more gentle tempo jazz or instrumental. They both have a similar midbass/ low mid tonality, though their treble is quite different and Mentor doesn’t have the same tonal weight in the sub registers.
I do definitely think the Canpur sounds more like Mentor than Anni23, but it has articulation in the treble rivaling Anni23.
If you like piano, CP622B is the best at that in particular to date. Very difficult to nail the full range of a piano‘s entire scale, especially capturing the nuance of the harmonics and ring in the upper mids, as well as the weight and sustain of the lower octaves. I have a piano track that of the hundreds of iem’s I’ve tried, only about 6 sound “Lifelike” with it, and of those 6, maybe 3 make me go wow. The best, CP622B made me feel like I was outside the realm of what IEM’s can do and almost convinced me it was headphone-tier imaging and outside of head. So tonality + holography/ nuance, very special