Short answer: the Penon Vortex. It ranks #754 of 1291 in-ear headphones by sound quality, rated 3.6/5, at $199; the Kiwi Ears KE4 ranks #821, rated 3.5/5, at $199. Close enough in price that the sound-quality gap is the deciding factor.
What the Penon Vortex does well: A broadly balanced tuning with a preference score of 69 against the Harman target. The catch: Treble about 2 dB below target from 3 to 10 kHz, which can sound dull or veiled next to brighter headphones.
What the Kiwi Ears KE4 does well: Bass is clean and well controlled from the isobaric dynamic pair, landing right on target from 20 Hz upward across 37 measurements. The tradeoff: The upper mids and presence sit about 4 to 5 dB below target, with a 7.4 dB dip near 6.5 kHz, so vocals and instruments lose bite and the sound can feel veiled.
Buy the Penon Vortex. It is rated higher for sound quality than the Kiwi Ears KE4 at the same price, so only choose the other one for a particular feature it does better.
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A broadly balanced tuning with a preference score of 69 against the Harman target.
Penon Audio $199 eBay
Bass is clean and well controlled from the isobaric dynamic pair, landing right on target from 20 Hz upward across 37 measurements.
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Specifications Side By Side
| Penon Vortex | Kiwi Ears KE4 | |
|---|---|---|
| Price | $199 | $199.00 |
| Ranked | #754 of 1291 in In-Ear Headphones | #821 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 69 (median of 3 squig.link measurements, calibrated to AutoEQ) | 67 (median of 37 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.54 dB standard deviation | 2.17 dB standard deviation |
| Tonal Tilt | -0.04 (negative is warmer, positive brighter) | -0.84 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-5.3 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-0.5 dB at 30 Hz) |
| Connection | Wired (3.5mm / 4.4mm) | Wired |
| Driver Type | Dynamic | Hybrid |
| Drivers | 1 Dynamic (10mm DLC & beryllium-plated) | 2 x 10mm dynamic (isobaric) + 2 x balanced armature |
| Impedance | - | 28 ohms |
| Sensitivity | - | 102 dB/mW |
| Frequency Response | - | 20Hz - 20kHz (Manufacturer specified) |
Frequency Response Compared
Both headphones’ measurements overlaid on the Harman target. Above the target sounds louder in that range, below it quieter. Each curve is the median of several independent measurements, shifted so its 500 Hz to 2 kHz average sits at 0 dB, so only the tuning is compared.
Measurement data: the Penon Vortex from harpo, jaytiss and tgx78; the Kiwi Ears KE4 from aden, aftersound, atechreviews, audioamigo, banzai1122, bloomaudio, boizoff, cammyfi, cqtek, dl, eliseaudio, filk, flare, gadgetrytech, harutohiroki, hobbytalk, iemworld, jaytiss, joshtbvo, joycesreview, kazi, kuping-sensi, listener, lown-fi, obodio, practiphile, pw, silicagel, sl0the, soundcheck39, soundignity, superreview, theaudiostore, therollo9, timmyv, treblewellxtended and vortexreviews, all via squig.link.
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