Kumitate Lab Corona
- Driver count: Three balanced-armature drivers
- Impedance: N/A
- Sensitivity: N/A
- Key feature(s) (if any): N/A
- Available form factor(s): Custom acrylic IEM
- Price: 70,000 円
- Website: www.kumitatelab.com
Starting off with the Corona feels a tad awkward because – ironically – it’s the most unique of the three monitors. As we’ll explore later, the Meteo and Sirius both emit a spacious, open and airy sound aided by a tightly controlled mid-bass and peaks along 7 and 12kHz. Conversely, the Corona is an intimate piece tailor-made for vocal reproduction. Most of its frequency response serves the midrange, where its buttery, warm and organic tone rekindles vague recollections of the Warbler Audio Prelude and Earsonics EM10. It outputs a similarly modest soundstage (though one deeper and wider than the former) and maintains a similar sense of coherence as well. Notes come through not by sheer clarity, but through balance and linearity – no one range overtaking another, so the instruments within exist in harmony.
The Corona’s low-end resembles a slight downward slope. There’s ample mid-bass content for impact and punch, while the sub-bass emphasis provides admirable gusto and great rhythm. Although okay extension limits it from becoming a true all-rounder down low, it still rumbles effectively with heavier tracks like Eminem’s The Ringer. And, with recordings where the bass is better balanced against the rest of the mix, that visceral-ness takes a step back and becomes favourably less apparent. The mid-bass sits in-line with the midrange, but a lower-treble peak renders the presentation as a whole less rich and full than the Prelude, for example. Additionally, enough energy exists between the mid-bass and lower-midrange to give vocals proper heft and body. I would’ve loved to hear a touch more extension to further boost the Corona’s dynamic range, but as it is, it’s a very proper fit to its signature: Punchy, organic and clear.
The midrange is where the Corona takes centre stage; presenting natural, vibrant and engaging instruments – both clear and warm in tone. It benefits from the monitor’s uniquely linear upper-treble (relative to its bigger brothers) and achieves an emotionally resonant timbre. Though unlike the Prelude, it employs a 7kHz peak for airy and crisp articulation. This gives the Corona a more open, transparent response without much compromise in tone or melodiousness. The Prelude may be more analog and life-like, but the latter is comparatively more exciting, musical and clean. Midrange notes take up a large majority of the stage, with a lift centred around 2-3kHz bolstering its size. But, excellent linearity from 1kHz on gives the presentation a sense of completion; coherent from the chesty fundamental, to the vibrant tone, to the articulate release. Despite its slight compromise in technical performance, the Corona has my favourite midrange of the three: Sufficiently clean, seductively intimate, and organic and refined all at the same time.
Again, the Corona employs a 7kHz peak for air, which renders its lower-treble neutral-leaning. However, as we’ll soon see with the Meteo and Sirius, this emphasis is seamlessly integrated into the frequency response; linear, buttery smooth and teemed in headroom. It gives instruments great clarity whilst remaining sufficiently natural. This is the Corona’s last peak before it rolls off around 10kHz. This shows admirable extension, but it is the weakest of the three. As a result, its stage is more intimate and its imaging isn’t as precise. But, it does play into the in-ear’s romantic response, and it’s an admirable performer in terms of separation. Instruments are well-organised horizontally, with enough space to thoroughly fill the head. Finally, speed is great – imbuing snare drums and cymbals with impact. All in all, the Corona’s treble fittingly concludes its signature; natural, smooth and unintrusive, yet dynamic and engaging all the same.
The Corona’s midrange-first mentality makes it a strong performer with vocals and instruments alike. But, its clever treble and punchy bass extend its versatility beyond similarly-targeted IEMs; putting its proverbial feet on both worlds. As a result, if the following three aspects describe your ideal custom IEM, the Corona should definitely be on your radar.
Sweet, intimate and well-resolved vocals: The Corona’s balanced, well-structured and vibrant midrange makes it a shoo-in for genres like jazz, singer-songwriter, R&B and simpler pop productions. Vocalists like Jason Mraz, Tori Kelly, Alicia Keys and Emeli Sandé immediately come to mind, while contraltos like Laura Fygi and Diana Krall absolutely shine as well. This is a presentation ideal if you want an intimate, you-are-the-mic experience – resolved, layered and emotionally resonant. But, the Corona’s admirable extension allows sufficient headroom, so the stage never gets claustrophobic.
A natural tone with clarity and refinement: Once again, the Corona’s specialty is its lightly warm tone that emphasises the melodiousness of the midrange – seductive, sultry and oh-so-easy to listen to. Vocals are delivered with a meaty timbre, but a 7kHz peak adds cleanliness and refinement there as well. Instruments won’t sound overtly honky or ill-defined. They carry with them a clear leading edge, so contrast between the images and the black background is moderately high. This will prevent vocalists like Diana Krall from sounding overtly chesty or deep, and allow her natural raspiness to add some colour to the presentation. For vocal enthusiasts, this can be considered the best of both worlds.
Euphony and musicality without congestion: Despite the Corona’s more organic response, it remains relatively free of warm air permeating its stage and causing what hi-fi enthusiasts tend to call a veil. Although the aforementioned group may still find the Corona lacking in crispness due to its linear upper-treble, it still manages to conjure sufficient space between its images; creating an admirable sense of separation. Its 7kHz peak is crucial in making sure compromises like these are as minimal as possible, so the Corona can maintain its naturalness whilst being relatively versatile too.
The downside to the Corona’s midrange emphasis is its lack of dynamic contrast. For those whose playlists expand much further beyond vocal-reliant tracks, here are aspects the Corona won’t deliver – especially relative to its bigger brothers.
Pristine cleanliness and bounds of treble sparkle: The Corona has a decidedly linear upper-treble, which contributes to its organic tone and realistic timbre. However, this’ll be to the chagrin of those looking for bell-like clarity and crispness. The Corona is certainly smoother than some would like, so if you’re used to the energy of IEMs like the 64Audio A18t or the Campfire Audio Andromeda – and you’re not willing to compromise that slightly for tone – then look elsewhere.
A gutsy, impactful bass: Although the Corona’s low-end has decent physicality and tone, okay extension limits it from achieving greater guttural-ness, texture and dynamic range. Rhythm sections and percussion won’t ever feel empty, anaemic or dull, but it’s worth keeping in mind if you place more emphasis on the low-end than average.
Utmost stage expansion and clinical imaging: The Corona may have admirable air for the signature it’s going for, but it’s certainly the weakest of the three in that regard. If your preferences lie closer towards an operatic, theatrical presentation rather than a more romantic, lush and intimate one, then you’d be better off looking at the Sirius or Meteo.