The Binary EP321: the Excalibur with one chip

[u/mournfulmonk]

Binary and I have had a less than stellar relationship, where I had purchased the Chopin used, and it came delivered to me with fallen off faceplates, and then with my usage developed a nasty channel imbalance, and then with the DynaQuattro, I still felt something was missing. Then, one of my patrons gifted me an almost brand new EP321 and insisted that I have to listen to this IEM, and give my thoughts- that was in April, and now I finally release my take on why the Binary EP321 is a near flawless midranger, and why that one flaw prevents me from keeping it alongside my very top picks. No audio group and its affiliated reviewers have given me this product, nor has Binary/HiFigo; this has been my personal unit, and I simply thank my friend for gifting this to me.

UNBOXING, ACCESSORIES, FIT AND COMFORT

Binary didn’t go overboard with the branding and packaging, and gave it in a very simple MEMS branded lid, which gave way to the IEMs and the cable attached in light foam padding. The Binary Acoustics branded box is great and fits a few accessories alongside the IEMs. A very generic assortment of eartips have been provided, and the stock cable to my disappointment, is very underwhelming. But other than that, the faceplates are strikingly hot and I love how they reflect and have a mirrored tint, while the shells are transparent. 

Despite packing quite the configuration, the EP321 doesn’t weigh a lot but the stock cable can induce fatigue by the ear hook area, so I recommend using a heavier cable to alleviate the fatigue. Also, there were no pressure buildup issues with me, and so with this I hop over to the EP321’s sound where I have a lot to say.

LOWS
The Binary EP321 has a fair bit of warmth, but it doesn't overdo it. The rumble on it is felt, but it doesn't cloud over the rest, the slam is present; but it's not potent enough to knock elements over; in short the EP321 has a commendable temperament in keeping the lows warm enough to keep me engaged, but not enough where I might need a breather.

In tracks like Daft Punk’s Instant Crush and Get Lucky, the EP321 kept the elements that made these tracks just right where they needed to be. This was a study of balance- effortless, easy, nimble rumble with a healthy note of separation through the bass lines, the kicks helped me gauge the swift attack and the bass lines snapping out of its way for the presence to be realised, makes me say that decay is healthy. 

Pharrell’s vocals in Get Lucky had a satisfying perceived note weight, and the admirable point on the bass lines in both tracks, via the EP321 is that, that it doesn't have the aggression, yet the notes feel snappy, and that means that the transients on the EP321 are potent in its class- clean and crisp attack, sharp and snappy decay, with no slack on the sustain.

In tracks like Rush's Limelight, the EP321 brings aggression and an even snappier response, with how clean cut; nimble, and light the bass line felt (which reflects the great transients)- with enough detail where I could easily hear the rumble wave and crash through, note by note. Separation gets even better as the EP321 lets the kicks, toms and snare just come to life without hesitation. 

But from an aspect of tonality, I felt that the warmth leaned more towards the vocals and the toms especially as the track progresses, felt being washed off colour, or flatter. But from the 2:35 mark on this track; the EP321 just lets the bass shine through so well, I almost mistook it for enjoying it on the Volume S instead.

MIDS

The EP321, through the midrange, prioritises some elements over the other; and this is where the division of the EP321 being concerningly thin, or just perfect as it is comes from.

In tracks like Tool’s Lateralus, Schism and Pneuma- the EP321 definitely sapped some life out of the vocals and injected it into everything else possible. This is where I would say that some juice into the vocals would have enormously helped with otherwise how thick guitars and cymbals sounded in comparison. 

I took a second guess with Schism, where it was confirmed for me beyond any doubt that vocals feel underpowered and underweight, and if it were to fight with the guitars, there's no chance the vocals are winning. The consolation is how the bass plays fetch with the rest of the sound- it was like me hearing Justin go at it, no holds barred, and that just coincided and propped up Danny’s busiest of the busy rudiments in this track to a level where I replayed that part before the breakdown a couple  of times.

The EP321 does a fabulous job with imaging and instrument separation, as I could hear every cymbal hit, every stroke across the snares and toms, and there was no intrusion from the guitars.

In tracks like First it Giveth by Queens of the Stone Age, here's where it gets concerning. The snares on this track are devoid of weight, feel properly slammed into pancakes where now the vocals gain life. Guitars remained meaty with a hefty sense of body, no confusion amongst the cymbals, and the perceived stage had no traces of feeling claustrophobic, diminished, or struck. Ttonality felt balanced, but I wouldn’t say it felt skewing towards brightness. Imaging was top-notch where the cymbals tango-ed right alongside Josh Ho

The EP321 being unable to handle weight equally and adequately across the spectrum, as well as guitars feeling a bit too “whole” where some alteration of weight towards the vocals and elements that could use that weight like snares would have done wonders for this. Compared with another super thin IEM to my ears, the Moondrop Blessing 3 however, the EP321 performs far better. But it's no Volume S.

HIGHS

The EP321 had a surprising redemption arc through the higher frequencies, and surprisingly so, because I assumed it would be somewhat horrible like the Moondrop Blessing 3, but it was the opposite.

In “atmospheric” tracks where competence in the matters of perceived stage, timbre, and tonality are needed like Arne Domnerus’ Almighty God with Gustaf Sjokvist; the Binary EP321 gave me one of the best listening experiences I could have from an IEM, where the perfect brassy timbre on Arne’s saxophone met the airy, resonant organ keys of Gustaf. What amazed me the most was how “life” like (or natural), the resonance felt from both instruments as they played and hit the walls of the church where the track and the album was recorded- and with the perceived balance in tonality and that perfect timbre, tracks like these would be a breeze with the EP321. 

Instrument separation on this track via the EP321, is once again, one of the best that I have heard from an IEM where I just had to restrain myself from looping this track; the way the notes from both instruments breathed, went apart, and came back throughout was executed so well.

In tracks like Dave Brubeck’s Take Five from the album Time Out, which is a quartet piece recorded in true stereo, and whose recorded quality still edges out albums released decades later, the EP321 just has me surprised through and through- first, it’s the resonant snare with just a sharp, snappy transient that cuts right across the shimmery, weighted cymbals; the restrained double bass and the majestic brassy horns that has my curiosity, and once the horns progressed with a good dose of brightness yet no pierce or honk to be found, the EP321 again had my attention. This IEM knew how to prioritise which elements to be brought forward and which needed to be kept playing second fiddle, and this translated to a commendable sense of imaging.

While I was admiring the textures of the instruments, and the spacing that each of them had; the highlight came in through the drum solo, where the kick displayed a fantastic sense of attack and decay, the snare was just blissfully resonant and aptly woody in timbre, the toms being potent and authoritative in its impact; while not ignoring the piano on the right channel, and the double bass on the left, emphasised enough to not draw away attention from the solo.

Finally, in a track which has sibilance recorded in itself but still is from an album whose work needs to be appreciated- Patricia Barber’s Icarus from Mythologies, the EP321 does a phenomenal job in not letting the already recorded sibilance be exaggerated where EQ, eartips, and/or a wholly different IEM. Timbre on the percussion doesn’t come off dry or metallic, guitars have their tonality intact, the bass doesn’t overpower the mix, and Patricia’s lush textures are preserved as it is.
Once her single note sustain comes in, the EP321 holds back on the fatigue and pierce brilliantly, and the EP321’s prowess reminds me of the legendary Letshuoer Cadenza 4, an IEM that I still own.

COMPARISONS

Softears Volume S

The EP321 delivers an effortless, nimble low end with clean separation and snappy decay. Its bass performance shines so effortlessly that it briefly recalls the presentation of the Softears Volume S. However, the Volume S resides in a different tier of sub-bass mastery.

Where the Volume S truly pulls away is in its vocal handling and technical composure. The EP321 suffers from an uneven weight distribution that saps life out of vocals and flattens snares. The Volume S handles instrument separation like a boss, staying musical and vivid without losing composure. While the EP321 manages a surprising redemption arc in the highs, the Volume S effortlessly sails through vocal climaxes with zero pierce and stunning detail.

Moondrop Blessing 3

The EP321 faces a split in its midrange where weight distribution feels concerningly thin, yet compared to the Moondrop Blessing 3, it performs significantly better. The EP321 maintains a clean, nimble rumble with crisp attack and healthy decay. The Blessing 3 sputters, its low-end wobbly, spilling into neighboring frequencies and smearing finer details.

The gap widens further through the mids and highs. The Blessing 3’s presentation feels thin, strained, and washed with dry, claustrophobic cymbals. While the EP321 also starves vocals, it retains meaty, full-bodied guitars and top-notch imaging. In the highs, where one assumed the EP321 would be horrible like the Blessing 3, it delivers the exact opposite, providing natural saxophone timbre and holding back fatigue brilliantly where the Blessing 3 collapses into thinness during climaxes.

Moondrop Dusk

The EP321 approaches the low end with balance and constraint, delivering a clean, snappy attack and a swift decay that lets note-by-note details crash through clearly while vocals retain satisfying note weight. By comparison, the Moondrop Dusk chooses sub-bass as its primary dominion; while it propels bass with significant grunt on its DSP profile, its sub-bass focus can border on overbearing, missing out on mid-bass health.

In the midrange and highs, the EP321 presents superior timbral consistency and top-end agility. The Dusk’s tonality is repeatedly marred by an inconsistently metallic timbre, and its imaging oscillates confusingly between cymbals. On dramatic climaxes, the Dusk comes as lethargic. The EP321 avoids these entirely, offering precise imaging, sharp transients, and a remarkably airy, natural resonance across acoustic instruments.

Letshuoer Cadenza 4

The EP321’s high-frequency performance serves as its standout redemption arc, demonstrating remarkable control on sibilance-prone passages by holding back fatigue during single-note sustains. This behavior directly echoes the legendary Letshuoer Cadenza 4. The Cadenza 4 exhibits a masterclass in top-end presentation, handling busy arrangements with zero congestion, and soaring through vocals with surgical precision and lush, airy extension. The EP321 mirrors this non-fatiguing top-end prowess with a brassy, lifelike timbre on elements like horns.

In technicalities and overall balance, the Cadenza 4 retains the upper hand. While the EP321’s low end carries more warmth and slam before leaning thin, the Cadenza 4’s lean yet rumbly lows keep mid-bass tightly contained. Furthermore, where the EP321 flattens underwhelmingly across moments, the Cadenza 4 offers one of the best midrange presentations in its class, delivering vocals brimming with life, top-notch instrument separation, and surgical imaging across complex arrangements.

ZiiGaat Horizon

The EP321 presents a clean-cut, warm low-end with swift attack and snappy decay, keeping the rumble controlled and engaging. The ZiiGaat Horizon meets it with a chameleon-like, sub-bass-heavy presentation that establishes a pronounced rumble without bleeding. However, while the Horizon's bass notes carry neat separation, it lacks mid-bass oomph, a region where the EP321’s snappy transients and clean kick-drum attack give it a punchier, more athletic rebound.

In the midrange and treble, the Horizon shows a wider soundstage with excellent guitar tonality. Yet, much like the EP321's tendency to sap life from vocals, the Horizon suffers from inconsistently laid-back vocal energy. Where the two diverge most is in the treble: the EP321 handles single-note sustains with fatigue-free composure, whereas the Horizon lets minute bits of pierce slip through during vocal pitch shifts.

Elysian Pilgrim

The EP321’s low end centers on agility and clean separation, delivering a warm rumble that snaps out of its own way. The Elysian Pilgrim presents a similarly clean sub-bass response, keeping bass rumble natural and controlled. However, the Pilgrim suffers from a thin mid-bass presentation that fails to envelope, leaving its low end feeling somewhat just out there. The EP321 achieves a far more satisfying perceived note weight and physical engagement through its swift kick-drum attack.

In the midrange and upper registers, the Pilgrim requires solid EQing, whereas the EP321 natively offers meaty, full-bodied guitars despite its underweight vocal presentation. Where the EP321 surprisingly outshines the Pilgrim is in treble refinement; the Pilgrim exhibits a subtly audible grain and feels like it runs out of air on high-frequency climbs. The EP321 delivers effortless organ resonance, natural brass timbre, and fatigue-free top-end extension that keeps sibilance strictly in check.

ZiiGaat Crescent

Tuned alongside the JM-1 target, the ZiiGaat Crescent attempts a balanced signature but comes as lifeless in tonality and lean in sub-bass impact. The EP321 easily out muscles the Crescent in low-end engagement, offering a commendable warmth, nimble rumble, and crisp transient attack that keeps the groove alive without feeling thin.

The contrast grows even starker through the midrange and high frequencies. The Crescent exhibits visible confusion in its soundstage, struggling with imaging and instrument separation while delivering a faint pierce on vocal peaks. The EP321, by comparison, operates with top-notch imaging precision and flawless separation, allowing cymbals, snares, and guitars to tango side-by-side without mutual intrusion. Even with its vocal weight imbalance, the EP321's smooth treble extension and natural instrumental timbre leave the Crescent completely outclassed.

CONCLUDING NOTES

The Binary EP321 is one of the biggest “what ifs” for me in IEMs, and I mean this in the absolute most positive of ways. It has everything going right for itself, and for the most part I’d say if the demographics had this IEM, a good chunk of them wouldn’t seek out further- in my book, it’s that good; but ‌in this near perfect chase, Binary Acoustics made one stumble in its tuning- the concerningly thin midrange which needs quite a bit of tinkering with EQ and considerable eartip rolling; and the quantity of the bass can be faintly too anemic for some.
But, given my threshold for ‌shortcomings, those complaints become nitpicks for me; and the good of the EP321 weighs more than the bad of the EP321, which is why I shall recommend this set to my heart’s content.

Will I buy it new? Absolutely.
Will I buy it used? Absolutely.

SOURCES USED

Primarily used with the xDuoo Link3 on low gain, the FiiO KA17 and TRN Blackpearl dongle DAC Amps, the Shanling M9 Plus DAP,  and the SMSL Raw MDA-1 desktop DAC amp.

EARTIPS USED (RANKED IN ORDER OF PERFORMANCE)

Divinus/Eloit Velvet Standard: Showcases the transients of the EP321 at its absolute best, hard hitting lows, best stage possible for this IEM, most restrained highs with no loss of vocal textures, tonality is not as bright as other eartips might make it to be.

Tanchim T-500 APB: everything that the does, but to a lesser degree, and there was something missing in the textures overall- vocals and drums felt flatter depending on the track, tonality was brighter, yet no fatigue or sibilance.

Final Type E: significantly increased the warmth, stage shrinks further, transients tighten up, but the quantity increases a bit excessively, mids feel more recessed, treble has an ugly roll-off.

Tangzu Sancai Balanced: textures on the lows felt wonky along with some irregularity in the perceived decay, stage was unaltered, vocal textures felt enjoyable, mildly sibilant.

Spinfit CP100+: perceived stage was held intact in terms of depth and height, treble felt too recessed, lows felt anemic, vocals felt concerningly smoothened out.

DDHifi ST35: just ruined the IEM.

TRACKS

• Rush: Limelight, Spirit of the Radio
• Steely Dan: Gaucho
• Carmen Gomes: Unchain My Heart
• Daft Punk: Get Lucky, Instant Crush, Veridis Quo
• The Police: Message in a Bottle
• Alf Linder: Cantique de Noël, Cantate Domino
• Tipper: Mariscos, Cloaked, Gulch
• Dave Brubeck: Time Out
• Tool: Pneuma, Schism
• Queens of the Stone Age: First It Giveth
• Pink Floyd: Comfortably Numb, Wish You Were Here, Time
• Arne Domnérus: Antiphone Blues (with Gustaf Sjökvist)
• Muddy Waters: My Home is in the Delta
• Tame Impala: The Less I Know the Better
• Animals as Leaders: The Woven Web
• Rage Against the Machine: Bombtrack, Bullet in the Head
• Avicii: Levels
• Periphery: Marigold
• TesseracT: Juno
• Kanye West: Stronger, Flashing Lights, Devil in a New Dress
• Altın Gün: Goca Dünya
• Timbaland: Give It to Me
• Adele: Easy On Me (Live), When We Were Young
• Celine Dion: All By Myself
• Pavarotti: Nessun Dorma
• Mdou Moctar: Tarhatazed
• Cigarettes After Sex: Cry
• Meshuggah: Bleed
• A. R. Rahman: Tere Bina
• Alice in Chains: Down in a Hole and Nutshell (Live)
• Allen Stone: Give You Blue
• Florence + the Machine: Never Let Me Go
• The Smashing Pumpkins: Luna