The Truthear Crinacle Zero IEMs have arrived! What follows is my 100% subjective, pseudo-review.
Disclaimer: I'm a professional classical musician, with many years of playing in professional orchestras, and as a result I have light hearing damage (incuding faint tinnitus) and my own idiosyncrstic audio preferences.
Further disclaimer: I like Amir's reviews and feel inclined to wish to agree with him.
Listening set up
Optical disc player: Yamaha Aventage BA-A1060 (CD, SACD, and Blu-ray)
Headphone amp: Schiit Magni Heresy
Audio selections
Béla Bartók: Dance Suite. Chicago Symphony Orchestra, Georg Solti. London/Decca (1981, CD).
Richard Strauss: Ein Heldenleben, Op. 40. Berliner Philharmoniker, Herbert von Karajan. Deutsche Grammophon (1959, remastered 2014, Blu-ray Pure Audio Disc).
George Frideric Handel: Messiah. Arnold Schoenberg Choir, Concentus Musicus Wien, Nikolaus Harnoncourt. Deutsche Harmonia Mundi (2005, SACD).
The Beatles: Abbey Road. EMI (1969, remastered 2009, CD).
Bob Dylan: Blood on the Tracks. Columbia (1974, remastered 2004, CD).
Maurice Ravel: Gaspard de la nuit. Martha Argerich. Deutsche Grammophon (1975, remastered 1995, CD).
Immediately ditching the waifu packaging nonsense, I was pleased with the build quality of the IEMs, and appreciated the inclusion of a nice faux leather case. I selected medium-sized ear pads, and carefully attached the delicate, polarized cable to the IEMs. Fit and comfort seemed fine.
My initial listening impression was, Wow! These are impressively detailed and clear, and certainly feature a substantial and impressive bass. Distortion levels and noise are definitely far below anything I could hear. The impression of soundstage width and depth was much better than I had expected.
But I soon began to wonder whether the Harmon Curve is actually a good fit for classical music: the sonic character has a bit of glare to my ears, I suppose corresponding to the curve peak at around 3khz. It's not always pleasant, with acoustic instruments. Or maybe I myself not a good fit for the curve? I think I prefer a flatter midrange. I'm tempted to pull down that 3khz peak a smidge and bring the midrange back slightly nearer to flat. The glare bothered me a bit less with vocal soloists in Handel's Messiah than with just the orchestra and choir, but it was something I noticed and didn't always find pleasing; this was the case with all three classical selections.
On to some rock and/or roll.
The sonic character of the Truthear Crinacle Zero IEMs as they snuggled the Harmon Curve like a blanket definitely pleased me more with popular music. I guess I shouldn't surprised by this, since classical music remains sadly a niche market, nearly drowned to oblivion by the so-called free market and pop music, and so the target of these products is overwhelmingly the vastly larger market. Are there classical music targeted IEMs? I doubt it.
But I will say I haven't enjoyed Abbey Road nearly this much in a good while, and these IEMs are responsible. With Blood on the Tracks, still Dylan's greatest work in my opinion, my thinking is definitely, yep, these are really, really good for popular music, and will surely please most people. They are clear, punchy, and exciting.
With classical, though? Hmm. I think I might want to at least pull down that 3khz peak some.
I concluded with Maurice Ravel's greatest work for solo piano, performed by the incomparable Martha Argerich, and the Harmon Curve suited the solo piano just fine to my ears. I'll have to do much further listening to see whether the "glare" is something I can truly live with happily for orchestral and choral.
Final comment: for the price, I'd say these are exceptional value. There is the question of how much the close adherence to the Harmon Curve is what you'd prefer. For me, it's definitely: these sound awesome for popular music! ...but perhaps the curve goes too far for classical?
Still, these are a pretty easy recommendation, especially for the price.