Aful Cantor VS 64 Audio U4S

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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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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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The 64 Audio U4s hits a compelling sweet spot: a 1DD+3BA hybrid around $1,100 that echoes the lush, bass-tilted character of the Nio while fixing key drawbacks. Packaging and accessories feel improved, with multiple tip options and the included M12 APEX module; APEX not only tailors bass but also relieves pressure for long sessions. Fit follows 64 Audio’s comfortable triangular shell; the vented DD asks for a slightly shallower insert than the all-BA models. Sonically, expect a sub-bass-oriented shelf and a treble profile that’s more lively and “zingy” than the Nio, with extra energy around the upper treble. The big caveat is 64 Audio’s muted 2–4 kHz region, which can set soprano vocals a step back on the stage.

Against the brand’s full-BA staples (think U12t/U6t), the U4s trades some pinpoint imaging and coherency for unmistakable DD slam and tactile “air pushing.” Extension at both ends is excellent, with upper-treble energy that makes micro-detail and reverb trails pop. It’s not the clean, conventional neutrality of something like a Monarch-style tuning; rather, it’s a deliberate, colored signature that delivers fun plus technical chops. Crucially, it fills a missing niche at its price and, in many respects, outperforms the pricier Nio, making the U4s a standout recommendation for listeners who want bass authority, sparkle, and engaging dynamics without going all-in on the flagship tier.

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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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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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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 64 Audio U4s hits a compelling sweet spot: a 1DD+3BA hybrid around $1,100 that echoes the lush, bass-tilted character of the Nio while fixing key drawbacks. Packaging and accessories feel improved, with multiple tip options and the included M12 APEX module; APEX not only tailors bass but also relieves pressure for long sessions. Fit follows 64 Audio’s comfortable triangular shell; the vented DD asks for a slightly shallower insert than the all-BA models. Sonically, expect a sub-bass-oriented shelf and a treble profile that’s more lively and “zingy” than the Nio, with extra energy around the upper treble. The big caveat is 64 Audio’s muted 2–4 kHz region, which can set soprano vocals a step back on the stage.

Against the brand’s full-BA staples (think U12t/U6t), the U4s trades some pinpoint imaging and coherency for unmistakable DD slam and tactile “air pushing.” Extension at both ends is excellent, with upper-treble energy that makes micro-detail and reverb trails pop. It’s not the clean, conventional neutrality of something like a Monarch-style tuning; rather, it’s a deliberate, colored signature that delivers fun plus technical chops. Crucially, it fills a missing niche at its price and, in many respects, outperforms the pricier Nio, making the U4s a standout recommendation for listeners who want bass authority, sparkle, and engaging dynamics without going all-in on the flagship tier.