Kiwi Ears have reinvented the KE4 - Is It a Worthy Upgrade??

https://www.linsoul.com/products/kiwi-ears-ke4-ii

Andrew Barlow (AndrewChoppa)

The Kiwi Ears KE4 II is the acoustic equivalent of a software patch that completely rewrites the codebase while keeping the same desktop icon. The original KE4 was a safe, warm-neutral, 2DD+2BA "meta-tuned" comfort blanket. I reviewed it over on Headfi.org. The KE4 II completely bins that layout, transforming into a 1DD + 2BA + 1 Microplanar tribrid monster designed to target modern target curves with laboratory precision.

Thanks to Linsoul for providing this for review. The KE4 II retails for $199 USD and is available from the Linsoul store.

The Spec Sheet Chemistry Pack

These guys have an impedance of 13 ohms and a sensitivity of 104 dB/mW.

The Low-End Engine: Out goes the dual isobaric dynamic driver setup. In comes a single 10mm bio cellulose dynamic driver doing solo heavy lifting for the sub-bass shelf.

The Vocal Core: A custom dual balanced armature setup optimized strictly for the midrange and lower treble boundaries.

The High-Freq Weapon: A custom microplanar ultrasonic tweeter replacing traditional BA tweeters to squeeze out ultra-treble past 20kHz with virtually zero metallic or "plasticky" timbre.

The Pipeline: A 3-way passive crossover pushing frequencies through three independent, meticulously routed sound tubes.

What’s In The Box??

It’s a simple black and white affair. Open up and 2 silver faceplates stare up at me. If you look closely (ok, my old eyes needed a picture zoomed way in from my phone), there’s intricate lines all over the face. They’re engrained as it’s a smooth finish, with Kiwi eras written in the middle. Linsoul states they are all hand crafted from medical-grade resin, then the faces are individually decorated and hand polished. Wow!

They’re of medium size and weight and they fit well in my side holes.

3 little air vents sit on the side to relieve air pressure. They look good. Not fancy but good.

We get a faux leather (might be plastic) case, a brown braided modular cable (yay!!) that has no memory or microphonics – I like the colour! Also 1 set of 3 size tips and 4 replacement nozzle filters. All standard but fine. Definitely no complaints.

Tonal Breakdown: Where the Science Hits the Ear

I’ve gone different this time – all my listening for this review is on the Jade Audio Gigas One desktop amplifier (still can’t compute that – it’s tiny!) and fed by the xDuoo CDM-10 tube cd player. I’ve  pulled out a bunch of old cds that used to get a million rotations when I was a young buck!

Clean-Cut Bass

If you like your mid-bass bleeding into your vocals like a cheap pen on wet paper, you’ll hate these. The KE4 II features a brutal, precision-engineered 8dB sub-bass shelf that aggressively cuts off at exactly 200Hz (source: Squiglink for all frequency measurements). This means your sub-bass rumble hits like a physical kick to the eardrum, but the lower-mids remain separated, clean, and entirely unbothered by the chaos below.

The Flatline Midrange

From 200Hz to 1kHz, the frequency response graph looks like someone died on a hospital monitor. It is entirely flatlined and uncoloured. Vocals are presented with a dry, studio-monitor realism. If the recording artist was having a bad day or the mix engineer was asleep at the console, the KE4 II will gladly expose them.

The Anatomy Compensation Treble

Thanks to the fast transient response of that microplanar driver, the ultra-treble stretches out effortlessly without creating that ice-pick sibilance that usually forces you to turn down the volume after twenty minutes.

And on the above setup, I’m getting a smack of bass, very well-balanced midrange and treble that provides resolution and sparkle without any harshness. These seem to lean V-shaped, and for me, that’s a good thing! Or at least neutral with a bass boost.

Turn these up on Great White’s Once Bitten cd, track – On The Edge, and bass hits like Mike Tyson in his prime. Guitars sound so natural and alive and Jack Russell’s voice (yes, that’s his real name….) is front and centre and sounding great but he’s not in my face. 0 honk, 0 shout, but great body and weight. And resolution on these for sub-$200 is simply amazing!!! I can hear the bassist fart at 3:32. Well slight exaggeration but they are open, airy and very resolving up top.

On the same cd, Rock Me has the funkiest, punchiest bass run. On the KE4  IIs on this setup, it is deep, clean, powerful and separated completely from the rest of the band. Did I say clean??? The guitar is crisp but not harsh and Russell sits there over the top but he’s in sync with the band, not above it!

When the drums kick in, it’s a party in my nut!!!!! These are so cohesive with a great bottom end.

Time to change cds. Europe’s 2^nd album (before Final Countdown), Wings Of Tomorrow and the first track – Stormwind. It’s powerful, gritty and fast. And the KE4 IIs handle it like a boss. What I notice on this track is the staging – it’s very wide and instruments are separated well within it. It’s much more lateral than it is spherical, but the width is pretty impressive.

On the first ballad, Open Your Heart, the guitar is high octave, and it sounds so clean and bright, but natural. Joey Tempest has such a powerful and commanding voice and the KE4 IIs showcase this so well. He’s right at the front but never over the top.

And the backing vocals are all around me, left and right, very sell spread out within the stage.

Finally, we swap cds again. Metallica’s iconic (and my favourite) Master Of Puppets. The Thing That Should Not Be is the pick off this great album. James Hetfield starts off with a deep guitar riff (almost bass guitar territory). It’s clean and commanding. Lars’ drum snaps are crisp but not crunchy and Mr Burton (Vale Cliff!) takes us into deep waters with his formidable bass run. And James on vocals is just so well balanced and rich, Natural with great weight.

Comparison Time

I’ll bring out the recently reviewed Erand Resonance 5 iems. Another $199 Tri Brid with a similar driver configuration. I recently very favourably reviewed them on my YouTube channel, AndrewChoppa’s Audio Addiction.

They both look great and fit well.

They have a fairly different sound signature, both enjoyable though in their respective ways.

Using Metallica’s Disposable Heroes for the first test track, the bass on both is deep and well separated from the rest of the mix. No winner here, both provide a deep, punchy and well controlled bottom end.

The mids on the KE4 II are very neutral and well balanced. Vocals are weighty but not forward. On the Resonance 5, they are pulled back a bit in comparison. I like a V-shape and the Resonance 5 have recessed vocals, giving a slightly more relaxed but maybe hollow presentation.

And treble on the KE4 II is fast. Lightning fast. Transients are quick and it’s clean and resolving up top. The Resonance 5s present a more relaxed and smoother treble, with less air and microdetail but many folk will prefer the smoother style. But the KE4 IIs are in no way shrill. They remain well on the right side of sibilance at all times.

On Metallica’s One, the technicalities do differ slightly. The KE4 IIs put out a very wide stage and images are separated well within that’s stage. The Resonance 5s are able to throw out a more spherical soundstage but they don’t go quite as wide as the KE4 IIs.

Overall, these are 2 excellent quality choices, especially in sub $200 category.

Both have quality, powerful bass which doesn’t bleed. The KE4 IIs are my preferred midrange and treble presentation (more of a party iem) but the Resonance 5s do throw a better 3d stage, so it really does come down to personal preference.

And my preference does go to the KE4 IIs, a huge step up from the KE4 OGs.

The Tech Verdict

The Kiwi Ears KE4 II trades the "fun and safe" identity of its predecessor for an analytical, highly resolving, and technically superior identity. By introducing microplanar tech into the top end and scrubbing the mid-bass bloat, they created an absolute detail-retrieval vacuum under $200. It's fast, incredibly articulate, and perfectly mapped out for those who want to hear exactly how a track was mastered—or where an enemy footprint just dropped on a virtual map. A huge thumbs up from me and string recommendation.

Linsoul do pay me to write these reviews, but it does not change what I write OR how I write it. If there’s something I don’t like about a product, you’ll know about it!