Aful Cantor VS ThieAudio Monarch MK4

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The AFUL Cantor delivers a balanced and neutral sound signature, praised for its exceptional upper air, treble extension, and pristine clarity. While the bass offers sufficient dynamics without being thunderous, and female vocals sound natural, some listeners might desire a touch more punch in the upper mids (around 2-3kHz) and find a slight peak in the 4-6kHz region occasionally noticeable. The premium build quality stands out, featuring a unique and stunning "star night" face plate, a thick but comfortable shell with a slender nozzle, and excellent accessories. These include a slightly microphonic but otherwise nice-looking flat two-pin cable and an exceptionally plush case typically found on far more expensive IEMs.

Graph comparisons reveal the Cantor's tuning shares similarities with models like the Moondrop Blessing 2: Dusk and the AFUL Explorer, but it distinguishes itself with superior detail retrieval and dynamics. It competes impressively against significantly pricier offerings like the Elysian Annihilator in technical performance, offering a smoother presentation with slightly less sub-bass focus. The overall sonic presentation is described as sophisticated, refined, and highly engaging, creating a sense of music surrounding the listener. Minor tuning preferences aside – wishing for a bit more upper mid presence and slightly less energy around 4-6kHz and 8kHz – the core sound quality is highly regarded.

Representing strong sonic value despite its price point, the Cantor earns a high ranking for its unique and beautiful design, premium feel, and exceptional technical performance. While acknowledging excellent cheaper options like the AFUL Explorer exist, the Cantor justifies its cost with its detailed, airy presentation and overall package. It's highly recommended for those seeking a neutral, high-performing IEM, though a demo is advised given the investment. Ultimately, the AFUL Cantor is considered a treasure, fulfilling over a year of anticipation with its beautiful aesthetics and uniquely engaging sound.

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Priced between $1,150 and $1,300 depending on custom faceplate options like the butterfly design shown, the Thieaudio Monarch MK IV boasts exceptional build quality with a large but well-contoured titanium shell offering a secure and comfortable fit. Key features include the innovative rumble switch for adjustable bass levels on the fly, a durable two-pin connector, and a solid feel that inspires confidence in longevity. While the included accessories are considered fair but unexciting, the shell's customization potential and rugged construction are major highlights.

Sonically, the Monarch MK IV delivers a detailed, exciting, and clean sound signature that stands as the best in the Monarch lineage. The rumble switch provides two distinct profiles: the red switch (no rumble) offers a balanced, tactful bass presentation, while the gold switch (rumble) adds a satisfying sub-bass shelf ideal for genres like hip-hop. Treble performance is notably improved over the MK III, though a 10k peak requires careful ear tip selection for some listeners. It trades blows with flagships like the $3,000 Annihilator (better sub-bass focus) and the $1,800 Elysian Apostle (more vocal forward), often matching or exceeding their technicalities while offering its unique tuning flexibility.

Scoring a top-tier 9.8, the Monarch MK IV earns its place through a compelling combination of premium build, the highly functional rumble switch, and outstanding sound quality that feels both special and refined. While acknowledging the high price, it represents significant value against competitors like the $2,000 Thieaudio Valhalla or the fiddly Grand Maestro, offering a feature-rich, durable, and sonically excellent package that justifies its position as a current summit-fi favorite.

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The Aful Cantor presents a complex and frustrating case, offering what might be some of the most detailed and resolving performance under $1,000. The clarity, separation, and sheer resolution are described as "pretty nuts," positioning the Cantor as a potential benchmark for technical ability. It delivers a clean, smooth, light, and airy sound signature with a bass that is very fast, lean, and features a tight sub-bass rumble. At lower volumes, this presentation is highly enjoyable and non-fatiguing, making it exceptionally good for critical, quiet listening sessions where its technical prowess can shine without drawback.

However, this technical marvel comes with a significant and unusual caveat: it is physically fatiguing to the point of causing headaches and a ringing sensation in the temples after only 15-30 minutes of listening at moderate volumes (around 70-80 dB). This is not a fit or nozzle issue, but rather an inherent property of the IEM itself. The problem manifests as a shrill and overly intense quality in the treble at higher volumes, accompanied by a metallic timbre on tracks with lots of cymbals, making it unsuitable for energetic genres like K-pop, J-pop, or EDM. This shrillness is not fully solved by EQ and is believed to be related to the driver design, nozzle, or venting rather than just the tuning.

When compared to peers, the Cantor is more resolving than the warmer, fuller, and smoother Letshuoer Supernova but falls short of its natural timbre. It also can't match the Monarch MK3 as an all-rounder, which offers a more impactful bass, better vocals, and a smoother, more engaging experience. The Cantor's vocals are also a weak point, being recessed, light, and borderline thin. The final recommendation is to definitely demo these first; they are only easy to recommend for those who listen at very low volumes (under 60 dB) and are not sensitive to treble intensity, as its scaling at normal listening levels is poor.

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The Thieaudio Monarch MK IV presents two distinct tuning options, elevating its versatility. The balanced switch delivers a clean, smooth, and slightly airy presentation, offering a refined all-rounder sound that's very detailed, well-layered, and resolving – essentially a direct upgrade to predecessors like the Monarch MK3 and Top Pro, with slightly more treble detail and air. Conversely, the bass switch provides a significantly fuller, warmer low end with punchy, well-textured bass and a tamer upper midrange, addressing criticisms of thinness in earlier models and offering a specialized, engaging listen for bass-heavy genres.

Technically, the MK IV sits comfortably in the $1,000 tier, offering a slight bump in detail retrieval, refinement, and smoothness over the MK3 and MK2, comparable to the Dunu Glacier and Prestige LTD. While not a giant leap, the dual tuning options make it arguably a better all-rounder than single-tuning competitors; the balance switch excels with acoustic, classical, and cleaner genres, while the bass switch shines with rock, metal, R&B, and pop. Build quality is improved with an all-metal shell, though the flimsy cardboard case is a notable disappointment. Vocals are smooth, balanced, and enjoyable, though sets like the Monarch MK2, Mystic 8, RSV, or Arcanis offer more forwardness or unique character. Bass quality is excellent for most, though pure bass enthusiasts might prefer models like the Thieaudio Origin for its unique texture.

Ultimately, the Monarch MK IV is a highly compelling endgame option for the vast majority. It combines strong technical performance with exceptional versatility through its two excellent tunings, covering a wide genre spectrum effectively. While value-focused options like the Top Pro, Volare, or Mega5EST offer similar technicalities at lower prices, the MK IV's refinement, tuning flexibility, and slightly superior performance make it easy to recommend. It allows listeners to leave the hobby satisfied, provided they resonate with its sound – though chasing marginally better flagships involves steep diminishing returns. The king might be debatable, but the MK IV is undoubtedly a very solid $1,000 contender.

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The AFUL Cantor lands as a flagship all-BA set with 14 balanced armatures at $800, packaged with a great-handling nylon cable and a handsome shell. The catch is fit: a very long nozzle with a metal insert demands a deep insertion, and comfort varies widely; AFUL’s stock tips are essentially required to keep that nozzle from poking and to restore some flex. Build and presentation impress, but the ear-fit can be fussy and the shells tend to stick out.

Tuning trends U-shaped: a lower-mid dip into a hefty sub-bass boost, relaxed upper mids, and noticeable upper-treble energy. When seated correctly, the set delivers crisp transients with a touch of “planar-like” pluck, good imaging, and clean BA bass that favors electronic thump over kick-drum slam; with the wrong tip or depth it swings to brittle/bright or muted. The midrange can read a bit thin, so the contrast comes more from bass/treble edges than from vocal saturation.

Compared with Symphonium Helios, both are all-BA and graph-adjacent, but Helios leans vocal-forward and smooth while Cantor is the more contrasty, fun listen that trades mid presence for excitement. Net: technically capable and competitive when dialed in, yet compromised by comfort and tip dependence. Final verdict: 3/5 stars—a better match for listeners with deep pockets and deep ears.

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ThieAudio Monarch MK4 comes in at $1,150 with a tribrid array—2 DD + 6 BA + 2 EST—a chunky stock cable with friction-fit swappable terminations, and a genuinely excellent, in-ear-operable “Rumble” bass switch. The new metal shells look tidy, but the fit is very large; on average ears it tends to sit a bit out of the concha and feel unstable (seal is doable, comfort is mediocre). Build details like the firm chin slider are nice, yet the cable bulk and loose termination retention detract from daily use.

Tonally, stock MK4 aims for a clean-neutral presentation with a meaty, sub-bass-focused lift, lively upper registers, and excellent extension. The flip side is a slightly dry / clinical character with a hint of treble hardness that can leave notes feeling a bit bodyless. Engaging Rumble mode thickens the curve from ~300 Hz down—more warmth and weight, bordering on “gigabass” territory—making the set fuller and more fun, though arguably too bassy for purists. Staging and imaging are solid, and resolution is high, but macro-dynamics land behind peers; compared side-by-side, sets like Dunu Glacier and 64 Audio U4S feel punchier, while Valhalla sounds warmer, smoother, and more effortlessly resolving.

Overall, MK4 is a technically capable tribrid with two distinct tunings on tap—clinical-clean stock and warmed-up Rumble—but it’s held back by fit size, cable quirks, and that slightly wooden bass texture. For listeners chasing a bright-leaning neutral with legit sub-bass reach (and who can accommodate a big shell), it’s a compelling try; in this lineup, though, it settles at a three-star recommendation next to more engaging or comfortable alternatives.

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This is AFUL’s flagship science project: the Cantor packs 14 BAs per side (28 total) and a heap of buzzword tech—Dual-Channel Acoustic Maze for sub-bass, non-destructive direct-drive topology, and multi-dimensional crossover trickery that reads like Star Trek schematics. The housing even extends a stainless-steel nozzle to the tip’s end to bypass tip coloration—smart for consistency, dicey for ears with wide-bore silicones. Stick to the stock silicones or better yet foams to calm treble and avoid any scrape-risk.

Sonically it’s a hyper-resolving analyzer: every band is so present that volume tends to go down, not up, and mediocre recordings get roasted on the spot. Imaging is precise but a bit less cohesive than simpler sets; stage stays as the track dictates, while separation feels like a mixing desk with 14 faders. The sub-bass dives shockingly deep for an all-BA—think whisper-low “whoomp”—yet it isn’t a bass-monster; overall balance leans revealing rather than lush.

Pairing matters: clinical amps make it razor-edged, while warmer sources (R2R, iFi, RME-ish) and foam tips smooth it into addictive detail. At $800 it isn’t the one IEM to rule them all; it’s the specialist tool for listeners who want to dissect space, mic technique, and mix decisions—more control room than mosh pit. Cable and case are solid (4.4 mm balanced), and a tuning switch would have been nice, but for the right kind of nerd this thing lets you become the squig.

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AFUL Cantor is a 14-BA, ~$800 set that looks premium and shows off its acoustic maze tubing through a semi-transparent shell, with faceplates in Star Knight or Marine Echo. The fit can be tricky: a long metal nozzle wants a deep insertion, and short tips won’t seal; longer tips like SoftEars Ultra Clear or Dunu S&S keep the nozzle covered and the tonality stable. The stock nylon cable feels nice but is very microphonic, making a swap advisable. Measurement quirks from shallow insertion are misleading—proper deep fit removes the apparent treble spike and reflects what’s actually heard.

Tuning follows the AFUL house sound: a mild U-shape, fairly neutral with a brightish tilt. The maze tech gives BA bass surprising decay and texture, with neutral mid-bass and a touch more sub-bass focus—close to a DD feel, if not identical. Mids sit clean; female vocals sound natural and sweetened by the steady rise through the upper-mids, while a gentle ~300 Hz dip makes male vocals and lower-octave instruments a bit lean. Treble is smooth yet energetic, with standout extension (impressively achieved without ESTs); it hovers near the upper tolerance for brightness but remains controlled with the right tips.

Technical performance is where Cantor shines: top-tier resolution, precise imaging, and a notably wide soundstage—great for detail retrieval and gaming, where positional cues pop (think footstep clarity in FPS titles). Versus Performer 7, Cantor trades P7’s fuller low-mids and better male vocals for cleaner female vocals and a more even treble. Against 64 Audio U12t, Cantor’s bass quality impresses, its mids differ (U12t’s 3 kHz dip adds sweetness but can feel odd), and Cantor’s treble sounds smoother; both resolve at a very high level, with Cantor edging imaging and stage width. Overall: an excellent but not universal pick—cable microphonics, deep-fit demands, and slightly thin lower mids mean careful matching to preferences. For detail lovers with female-vocal libraries who tolerate a brighter treble, it earns a one-star recommendation; others may prefer alternatives in this bracket.

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AFUL Cantor presents as a premium 14 balanced armature set with solid build quality and a distinctive elongated nozzle, but that nozzle makes fit unusually finicky for an 800 dollar IEM. Finding the midpoint between shallow and deep insertion is critical, as too shallow makes the treble peaky while too deep collapses the stage and dulls extension. The whole experience of tip selection and insertion feels overly complicated at this price, with questionable payoff for the effort.

The tuning follows a very U shaped profile where sub bass and upper treble act as the tent poles and the entire midrange sits relatively flat and lean. Bass is tight and textured but heavily sub bass focused, with very little mid bass weight, leading to a clean yet somewhat sterile presentation that leaves lower mids thin and lacking body. Mids themselves are clean and reasonably natural thanks to a restrained ear gain region, but the combination of reduced mid bass and elevated upper treble pushes the overall balance toward a cool, unengaging character rather than a rich, everyday listen.

Where Cantor excels is in technical performance: resolution, micro detail and treble clarity are strong, and the BA timbre is impressively well controlled, giving the set a crisp, analytical edge. However, the reliance on upper treble energy to restore presence can become fatiguing on bright material, and the otherwise good stage is highly dependent on nailing the exact fit, making the presentation inconsistent from listener to listener. Taken together, Cantor feels more like a high priced specialist tool for those who prioritize technicalities over warmth and musicality than a balanced, broadly appealing flagship all rounder.

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AFUL’s $800 flagship pushes hard on engineering: 14 balanced armatures, a five-way network, 3D-printed shells, and the brand’s acoustic maze that coaxes unusually textured, dynamic-driver-like bass out of an all-BA setup. Packaging is “classic AFUL”—nice case, multiple tip sets, cleaning brush—but light for the price, and the cloth-sheathed cable, while beautifully machined and very low resistance, is highly microphonic. The big talking point is the metal nozzle extension: tips must be pushed down to the rim for a deep fit, which optimizes tonality and treble smoothness. Comfort varies wildly by ear; some report irritation, and the long nozzle feels fragile if dropped.

Sonically, this is AFUL’s house sound elevated: a slightly warm-neutral balance with clean, meaty lows, natural mids, and an upper-mid/treble that sits right on the edge—silky and detailed with a deep fit, but bright and fatiguing if worn shallow or with the wrong tips. It is extremely revealing of mastering quality, rewarding good recordings with elite microdetail, imaging, and a huge, tall stage that can hang with far pricier sets. A mild impedance adapter (or higher-Z source) can warm the tone and shave some air, though at a small cost to sparkle and openness.

Against AFUL’s own lineup, the closest kin is the Performer 7: similar flavor, less resolution and scale, but a far better value. Cantor is the brand’s “thesis statement”—the most complete execution of its tuning—with true summit-fi technicals at a mid-summit price. Still, it carries caveats: fit sensitivity, that microphonic cable, and accessory stinginess. Recommended only if the budget is comfortable, a deep, stable fit is achievable and comfortable for long sessions, and AFUL’s warm-neutral house sound already hits the spot; for everyone else, the P7 or Explorer make safer picks.

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The ThieAudio Monarch MK4 is a premium IEM that earns a spot in the S-tier for competitive gaming, offering a significant upgrade over its predecessor and A-tier competitors. It features a unique rumble mode switch that adds a satisfying low-end punch and weight without muddying the detailed, reference-grade tuning of the standard mode. While the CNC aluminum build feels exceptional, the design is a bit bulky and heavy, which can lead to some comfort issues during very long, multi-hour sessions.

For gaming, the technical performance is nothing short of phenomenal. The imaging is holographic and the depth perception is absolutely exceptional, providing a critical advantage in tactical shooters like VALORANT where tracking footsteps through walls becomes incredibly precise. The wide and deep soundstage pushes sounds off the player, creating an immersive experience. While rumble mode is preferred for titles like Call of Duty, the standard mode's clean and detailed signature shines in battle royales like Apex Legends, though the 2-4k range can make gunfire a bit shouty at higher volumes.

This is also an absolutely amazing set for music, delivering an elevated level of technicality and resolution. The standard mode offers a fast, clean, and neutral listen with great detail retrieval, while the rumble mode provides a weightier, more engaging bass profile for tracks that benefit from the extra warmth and punch. Ultimately, it's a very high-end IEM that delivers a top-tier experience for both competitive gaming and critical music listening.

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Monarch MK IV lands as a top-three set, sitting just behind the PMG APXSE and CP622B, and it earns that spot with an evolutionary design: a single, tactile rumble switch that can be flipped while the IEM is in-ear—no fiddly pins, no tools. In stock (red) mode it’s a vocal-friendly tuning with restrained mid-bass; engage the switch and the low end lifts, adding note weight without smearing the mids. The shell is metal, build is tight, and all the BAs are Sonion, signaling premium parts and execution.

Low-end performance nails both 808 drops and classic rock kick drums (“When the Levee Breaks”) with satisfying slam—better with the switch on—while bass guitar texture (pulls, plucks, string ring) stays articulate into the lower treble. Vocals are clean in stock mode and gain a pleasing husk and density with rumble engaged, making artists like Neil Young and Mark Knopfler pop. Upper mids/treble avoid glare and long-term fatigue, turning this into a true “sofa set” for hours-long sessions.

At $1,400 it competes shockingly well against far pricier summit-fi gear—no veil, no masking, just balanced resolution and a flip-to-taste bass shelf. Compared to Valhalla, the MK IV’s instant two-flavor flexibility pushes it ahead on value; bone-conduction curios like Origin feel more niche by contrast. Net: the best ThieAudio to date, an easy recommendation, and likely the new #3 overall—thanks to that simple, game-changing rumble switch that future proofs the tuning.

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ThieAudio Monarch MK4 arrives with the usual hype and a clear step-up in presentation: a thick, high-quality premium cable with interchangeable terminations, plenty of tips and tools, and a handsome case. The shells move to an all-metal build with a resin faceplate and a bass switch, while the internals stack up to 2DD + 6BA + 2EST in a four-way crossover. It is a big set—more long than wide—so smaller ears should test fit first, but the overall finish and hardware feel decidedly upscale.

In quick listens, the normal mode is the sweet spot: clean, powerful and immediately great without obvious quirks. Flipping the switch to bass mode turns things thunderous—fun for a moment—yet can nudge vocals out of balance on bass-heavy tracks, making the standard setting the better choice for everyday use. Early take: a confident, polished evolution of the Monarch line that favors balance and refinement in normal mode, with optional low-end excess on tap for those chasing extra rumble.

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The ThieAudio Monarch MK4 presents a well-extended, refined treble that measures cleanly and feels more polished than earlier iterations, though the overall tonality can read a touch thin. Against its sibling Valaha, the MK4 trades warmth for a clearer top end, keeping the presentation crisp without obvious harshness.

Between the pair, the MK4 takes the edge on technical performance—notably resolution—thanks to a bit more upper-treble energy and a more controlled bass shelf, while the Valaha offers extra mid-bass thump and a slightly warmer tilt. Net result: the Monarch MK4 remains a standout around $1,000, balancing precision and extension better than its stablemate.