Tada!
(If I ever get un-lazy enough to take and edit a picture, I'll place it here in the future. 
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vs. Warbler Audio Prelude
The Prelude and the Black have a fair share of similarities. One of them would be upper-midrange presentation. Both have palpable energy at 3kHz which gives instruments this lively, forwardly energy. The Prelude, though, has more energy around 500Hz-1kHz, which gives it a meatier, richer and more organic timbre - especially when combined with its greater 5kHz dip. If the Black is your reference, the Prelude would sound marginally thicker and more nasally. The Black’s noticeable advantages are in stage construction. It has a blacker, deeper background, as well as a larger stage. The difference in width isn’t significant, but the difference in depth surely is.
(Keep in mind, I’m comparing the two on single-ended with their respective stock cables; spatial differences may become further exaggerated in balanced mode.) The Black’s 10kHz peak gives it a faster, sharper transient response, so notes are more hard-edged and articulate compared to the Prelude. But, the peak isn’t large, so the difference isn’t
staggering. It’s not gonna be a HD650-vs-HD800 sort of difference if you catch my drift. Though, because the Black does have good 6kHz energy as well, it’s gonna sound a bit more throaty than the Prelude. Instruments like horns will sound a touch honky-er, while the Prelude has the more natural, smooth release. Female vocals also have a more husky, smoky tone on the Prelude, while they sound wispier and raspier on the Black - again, by a
slight margin; the vocalist doesn’t suddenly develop a sore throat or anything. But at the same time, the Prelude’s organic warmth renders it a step behind the Black in terms of detail retrieval, layering and separation. Stage stability also goes to the Black. Its treble extension and resonator technology creates lower distortion, so the stage isn’t mucked up by warm air. Consequently, tiny nuances like reverb and decay come through more easily for a more transparent listening experience. In terms of left-centre-right separation, the Black performs more clinically. It segregates the three to a greater degree, which shows itself effectively when listening to songs with prominent panning effects. The Prelude’s notes are more bloom-y and less compact, so left, centre and right somewhat blend into each other. This is musical and intimate with more simply-arranged tracks, but it can make busier tracks more difficult to follow. Bass extension goes to the Black as well. There’s a more satisfying cadence with pop and EDM tracks, even though bass quantity isn’t far off. The Black certainly has more of a rhythmic drive.
vs. Jomo Audio Haka
While the Prelude is the Black’s tonal companion, Haka is its spatial one. Both portray similar levels of width, depth and left-right separation, but they differ in approach. The Haka has a much calmer 3-4kHz range - in fact, it seems like it dips where the Black peaks - so vocals are much more laid-back and calm. But because of this, they may come across slightly diffuse, especially with mixes that already attenuate that range. There’s a lackadaisical-ness to how instruments are presented in the Haka, that’s less exciting, intimate and vibrant than those on the Black. This is how it achieves its sense of depth - a bit of a compromise, admittedly. On the other hand, the Black gains depth by maintaining a more neutral sub-bass. The
projection of instruments is never overpowered by the low-end. The Haka is the reverse: It has a more guttural, lively sub-bass. In low-end heavy tracks like Sabrina Claudio’s
Don’t Let Me Down or Eminem’s
Lucky You, rumble takes precedence over vocal presence - especially considering the Haka’s laid-back upper-mids. Consequently, in order to maintain headroom and stage cleanliness, the Haka has a calmer mid-bass. The Black has greater mid-bass quantity and yet achieves equal - if not higher - headroom relative to the Haka. This is because of its superior treble extension. In left-centre-right separation, the two go blow-for-blow. The Haka has more apparent depth because of its withdrawn vocals, while the Black has greater stereo resolution. Sounds along the left-and-right-most edges of the stage have greater integrity and solidity, while they’re a tad less focused on the Haka. Both in-ears have a 6kHz peak for articulation, plus dips at 5 and 8kHz. So, transients have a bit of a feathered edge to them, but they’re still articulate nonetheless. The Haka’s upper-mid dip makes those top-end transients sound lighter and faster, while the Black’s are a touch more rounded and thick by comparison. Remember: We’re talking about the
transients here; not the notes. For reference, cymbals on the two sound similar, but the Haka generates more of a
pssst sound, while the Black leans closer towards a
psh-ssst sound. The Black’s 10kHz peak again gives transients a slightly brighter, harder edge, so its background is a touch less black compared to the Haka’s. Cymbals and hi-hats leave very slight traces of bright harmonics, while the Haka decays faster in a cleaner manner. But, the Black compensates in resolution. Despite strong articulation, the Haka’s images are softer and more wispy. The Black presents more solid, three-dimensional notes with greater physicality from transience to decay.
vs. 64Audio A6t
64Audio’s A6t is the outlier of the four in terms of tonal balance and presentation - a large contributor of that is its
tia driver. Unlike the other three, the A6t has noticeable energy in the upper-treble, which results in its crisp and prominently-detailed sound. But, this results in its transients being the least natural and smooth of them all as well. Compared to the Black, the A6t has a much
tizzy-er edge, because of palpable peaks at 7 and 12kHz. Details are more pronounced and clarity is higher too, but some coherence is sacrificed along the way. The Black has a more natural, organic response, but it certainly isn’t as crisp, dazzling or exciting as the A6t. Contrast between the A6t’s lively treble and its deep, rumbly lows give the in-ear a superior sense of energy and rhythm. Additionally, because of a greater 1-2kHz rise, the A6t has larger, weightier, denser instruments. This is crucial for its musicality and engagement, but it does concede imaging and separation by a hair to the Black. The Black is more capable at isolating its individual elements, while the A6t chooses to coalesce them to form a more singular, exhilarating,
in-your-face sort of image. Distorted electric guitars like the ones on Mark Lettieri’s Little Minx - for example - are crunchier and more satisfying to listen to. The A6t’s low-end emphasis lies closer between the mid- and sub-bass, while the Black’s is more mid- and upper-bass-inclined. As a result, the A6t has a more satisfying, more energetic cadence when listening to EDM drops, electric guitar riffs and kick drum rhythms. But, the Black has the more accurate, organic tone; utterly engrossing to listen to with upright basses and pianos. With these two instruments, the A6t’s low-end lacks a touch of warmth and resonance to sound completely accurate in my opinion. How the two compare in staging is one of the major reasons why I assumed the Black was a 5-6 driver, $1200-1500 in-ear in the first place. The Black competes very capably against the A6t in terms of stage expansion and spatial resolution. The two are equals in width, depth and height, but the Black has the advantage of headroom. Because of the A6t’s larger notes and louder transients, there isn’t much space left for instruments to breathe and render detail as they decay. The Black - again - is less crisp, vibrant and loud by comparison, but its laid-back delivery makes its details much easier to take in. Of course, which of the two you prefer will depend on your preferences. If you like more apparent detail, you'll definitely prefer the A6t's response. Finally, in overall tone, the two reside in a similar region of neutral-natural; mid-bass warmth offset by an articulate treble sandwiching a dense, rich midrange in the middle. But, they differ in timbre. The Black is more organic, laid-back and linear, while the A6t is more
rock-concert-like. Again, different strokes for different folks.
(and thanks to you and Kamil for bearing with my enquiring every week of when I would get my Black 
About 2 weeks for mine right now I believe give or take.
