For the past days I have been playing around with Hum Pristine v2 and 64 U18. While Tia fourte has very natural tone if not most, its treble even though extended the most, being harsh sometimes, didn't give it much easy listen compared to U18 (suggesting that Tia fourte should be used for good remastered tracks only) so eventually I stopped touching it after a while
M20 module is my most favorite part of U18. They key word "Balance, full and organic" . The best part of it would the layering capability and the overtone that i could hear from its upper mid.
So how does Hum Pristine vs 64 U18 M20? Pristine is a chameleon, it changes the sound signature on tracks even selecting the cable for it is quite challenge, sometimes it sounds harsh or just warm smooth and wonderful while U18 signature doesn't change with different music, it just makes everything feel immersive, layered and easy to listen to.
The first thing I notice when putting them on is resolution and transparency, they are on similar level, I can hear Pristine a bit clearer and more coherence but U18 has a bit higher resolution.
Low : U18 has a warm and fuller bass which rumbles more . Also it has a bit more depth and texture but Pristine's bass is more accurate, tighter, articulates more and hits a bit harder(expected from a ref-tuned iem).
Mid : The mid on Pristine is more forward while the mid U18 is even. Both have similar quality, natural tone and being emotional with Pristine a tad brighter and harsher in the upper mid though the harshness depends on tracks due to its revealing nature. The upper mid on U18 is more extended and smoother compared to Pristine. I do like the fact that vocal extended a bit more and has the lingering feeling after each note, this could give quite emotion sometimes.
High : Both have natural tonality and smooth but Pristine is brighter and harsher with poorly remastered tracks. On the other hand, U18 has more easy treble to listen to. Smooth, not overly warm, organic, laid back and extended. It's smoother not by all mean 100% though I can hear it being edgy sometimes. U18 it brings out detail a bit more in an effortless fashion.
Staging and imaging : U18 has better 3d dimensional staging with wider stage and better depth in case giving better sense of instrument placements. The biggest difference would be its layering capability is plain better than Pristine .It's not nice and day better but it's just noticeably better in everything. Nothing to expect here from limit of 2-drivers design and 18 ba with open ba is a bit overkill. I actually did a small comparison between U18 on Wm1a's balance and HD800 on mid-fi stack Bifrost/Valhalla, found that U18 has quite similar staging but fall short on Spatial cues and openness, already quite impressive for an iem.
This might not be a fair comparison since 2 of them are in different price bracket. If U18 is 89, I would give Pristine a 87 . The performance is not a big gap in Tier 1 ranking tbh but if you look at the asking price that would be another story.