Kumitate Lab’s NEXT 5! – A Comprehensive Overview of the Corona, Meteo and Sirius


Kumitate Lab Sirius

Technical Specifications

  • Driver count: Four balanced-armature drivers
  • Impedance: N/A
  • Sensitivity: N/A
  • Key feature(s) (if any): N/A
  • Available form factor(s): Custom acrylic IEM
  • Price: 90,000 円
  • Website: www.kumitatelab.com

Sound Impressions

The Sirius has a clear-cut focus on cleanliness and clarity. Although its smoothness and linearity harkens back to the Meteo, it differs from it in proportion and priority. The Sirius has a much lighter bass and a more present treble. So, it’s noticeably brighter and a touch thinner as well. Strong linearity prevents instruments from ever sounding metallic or insubstantial, but it’s still a signature that even marginal bassheads will find inadequate. Nevertheless, its response makes it a natural achiever in imaging and separation. It takes the Meteo’s already-outstanding size and adds height, so images feel further out of head. Note compactness and speed also create a more defined sense of geography. Warm and rhythmic it is not, but it resumes Kumitate Lab’s masterclass in spatial resolution at (relatively) modest prices.

The Sirius has an upper-bass-emphasised low-end with little in the way of sub-bass rumble and mid-bass warmth. As a result, it’s a response that’ll come across as light, calm and nonchalant. However, it’s technical performance should not be ignored. Despite its reservation, extension is excellent. So, bass hits always cut through with palpable definition in spite of its minimality. Strong linearity also ensures a rounded bass; neither hollow nor wispy. This comes paired with a natural tone, which gives the low-end admirable realism. The treble emphasis does colour it a tad bright in the end, but only by a slight margin. Once again, nimbleness and control score very high. This complements the bass’s density with detail retrieval and layering. It’s a shame, though, when this becomes something you have to look for, rather than sit back and enjoy. At the end of the day, the Sirius’s bass gets many things right. I simply wish there was more of it.

This reservedness in the bass directly affects the Sirius’ vocal presentation. Instruments are clean, crisp and brighter in tone. Thankfully, crucial lifts along 1-3kHz give notes enough density to avoid sounding metallic, incoherent or hollow. But, the Sirius’ laid-back low-end leave voices in dire need of warmth and body. Baritones like Michael Bublé and Rick Astley lose much of their gusto (gravitas) and the attitude they bring with it. On the other hand, raspier vocalists like Laura Fygi and Rod Stewart end up sounding throaty and hoarse; their rasps overtaking the lower fundamentals. But despite these tonal shortcomings, Kumitate Lab deserve massive credit in technical performance. Once again, layering, imaging precision and separation are some of the strongest I’ve heard at this price point. There’s a real sense of depth that sounds earned (rather than artificially recessed) and unwavering smoothness in every track it tackles. All in all, the Sirius has a midrange that’s clean, spacious and technically sound, even if its tonal balance could use some work.

With the Sirius, Kumitate Lab continues to impress when it comes to tuning treble. The 4-driver’s top-end is wonderfully crisp and airy, yet smooth and refined. Similar to the Meteo, it employs peaks along 7 and 12kHz – as well as a 6kHz dip – but the treble region as a whole is further elevated here. This gives the stage a more open ambience, but it brightens the monitor’s background and contributes to the tonal shortcomings we discussed earlier. Nevertheless, it’s a wonderfully clean treble with massive headroom that never ceases to remain smooth. This is particularly gorgeous when listening to cymbal crashes and ride bells – every ring, crash and sizzle rendered with crystalline clarity and air. But, the linearity with which it does so prevents any amount of harshness, tizzy-ness or fatigue. Simply put, it’s a top-end that balances cleanliness and refinement like it’s child’s play. It’s neither warm nor thick enough to be considered fully natural, but it solidifies Kumitate Lab as a benchmark with one of my favourite treble tunings since Lime Ears.

General Recommendations

The Sirius’s technical ability positions it as one of the best clarity-focused in-ear monitors in its price range today. If you’re in the market for a consistently smooth, neutral-bright IEM, these are what the Sirius can do for you:

Pristine, bell-like clarity with a sufficiently dense midrange: The Sirius has a top-heavy signature that drives its cleanliness and clarity. However, it does an admirable job structuring its midrange. Once again, its lean bass does leave instruments in need of warmth and harmonic richness, but the midrange remains surprisingly coherent nonetheless. If you don’t mind vocals sounding raspy – but not thinly wispy – if it means greater clarity, the Sirius is definitely worth considering.

A vast, open stage with excellent precision, layering and depth: The Sirius emphasises the Meteo’s strengths and structures an impressively vast stage – especially at its price point. Imaging precision and layering is reminiscent of in-ears almost twice the price, as its images boast excellent amounts of depth, width and height. The Sirius is a surefire contender for those looking for a grand, theatrical and operatic spatial presentation without losing engagement.

A bright-leaning – but smooth – timbre: Once again, the Sirius’s inherent tone makes it a shoo-in for fans of transducers like the venerable Sennheiser HD800. However, it pays its due diligence in avoiding sibilance just as deftly as its little brothers. It displays impressive tolerance for hotly-mastered tracks and maintains excellent headroom at all times.

Despite the Sirius’ technical achievements, its brighter tone and decidedly lean presentation limits its versatility quite a bit. If the traits of your ideal in-ear monitor are the ones below, the Sirius may not be the best fit for your needs:

Any amount of fullness from the bass: Proportionally speaking, the Sirius’ low-end gets the short straw. This is the main culprit behind its brighter timbre. Additionally, vocals end up sounding drier and raspier – articulative and detailed, but lacking harmonic richness and warmth. If a lush, laid-back signature is your cup of tea, the Sirius definitely won’t be.

A warm, natural tone: Once again, the Sirius’ treble emphasis gives it a clean image, as well as a brighter tone. Instruments may sound crystal clear and smooth, but they aren’t life-like in terms of timbre and hue. To those who prioritise an IEM’s tonal balance over sheer transparency and detail, the Sirius may prove too lean for your liking.

Dynamic energy and rhythm: The Sirius’ lean low-end also limits its dynamic range. Instruments like cymbals have impact, but there’s a missing sense of cadence when guitar riffs pop in, or in kick drum grooves, or in bass drops, etc. If you frequent genres like EDM or pop – or simply prefer a rock out presentation in general – the Meteo is a better candidate.

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About Author

Church-boy by day and audio-obsessee by night, Daniel Lesmana’s world revolves around the rhythms and melodies we lovingly call: Music. When he’s not behind a console mixing live for a congregation of thousands, engineering records in a studio environment, or making noise behind a drum set, you’ll find him on his laptop analysing audio gear with fervor and glee. Now a specialist in custom IEMs, cables and full-sized headphones, he’s looking to bring his unique sensibilities - as both an enthusiast and a professional - into the reviewer’s space; a place where no man has gone before.

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