Short answer: the Binary EP321. It ranks #314 of 1291 in-ear headphones by sound quality, rated 4.1/5, at $309.99. The Kiwi Ears Astral ranks #405, rated 4.0/5, at $299, $10.99 cheaper, which does not close the gap in sound quality.
What the Binary EP321 does well: The median of 7 hobbyist measurements gives it a very good Harman preference score of 75 with a 1.75 dB spread, and its mids sit within about 1.4 dB of target, so vocals and instruments sound natural. The catch: Presence sits about 4 dB low with a 5.6 dB dip near 5.8 kHz, so vocals and instruments lose some bite.
The case for the Kiwi Ears Astral: The median of 26 hobbyist measurements gives it a solid Harman preference score of 74 with a 1.77 dB spread, and its mids sit within about 1.4 dB of target, so vocals and instruments sound natural. The tradeoff: Presence sits about 4.7 dB low with a 6.1 dB dip near 5.9 kHz, so vocals and instruments lose some bite.
Buy the Binary EP321. It is rated higher for sound quality, and the $10.99 saving on the Kiwi Ears Astral is not enough to make up the difference.
Still deciding? The full Headphones rankings cover every ranked option.
The median of 7 hobbyist measurements gives it a very good Harman preference score of 75 with a 1.75 dB spread, and its mids sit within about 1.4 dB of target, so vocals and instruments sound natural.
Amazon $309.99 eBay
The median of 26 hobbyist measurements gives it a solid Harman preference score of 74 with a 1.77 dB spread, and its mids sit within about 1.4 dB of target, so vocals and instruments sound natural.
Amazon $299.00 eBayPrices on this page were last checked October 16, 2026 at 5:46 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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Specifications Side By Side
| Binary EP321 | Kiwi Ears Astral | |
|---|---|---|
| Price | $309.99 | $299.00 |
| Ranked | #314 of 1291 in In-Ear Headphones | #405 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 75 (median of 7 squig.link measurements, calibrated to AutoEQ) | 74 (median of 26 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 1.75 dB standard deviation | 1.77 dB standard deviation |
| Tonal Tilt | -0.43 (negative is warmer, positive brighter) | -0.74 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-0.8 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (+0.5 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Hybrid (1 dynamic + 1 passive radiator + 3 balanced armature + 1 MEMS) | Hybrid (1 dynamic + 6 balanced armature) |
| Drivers | 1 x 10mm dynamic + 1 x 6mm passive radiator + 3 x balanced armature + 1 x MEMS | 1 x 10mm dynamic + 6 x balanced armature |
| Impedance | 13 ohms | 23 ohms |
| Sensitivity | 122 dB SPL/V | 105 dB |
| Weight | 0 lbs (7.5 g) | - |
| Frequency Response | 8Hz - 40kHz (Manufacturer specified) | 10Hz - 22kHz (Manufacturer specified) |
| Built-in Microphone | No | No |
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 Binary EP321 from aden, aftersound, animagus, atechreviews, audioamigo, awsmdanny, elrics, jaytiss, kuping-sensi, lumerion, practiphile, precog, soundcheck39, superreview, takeitslow7 and tonedeafmonk; the Kiwi Ears Astral from aden, aftersound, arn, atechreviews, audioamigo, avishai, bassaudio, bloomaudio, cqtek, fernandagunsan, gadgetrytech, hobbytalk, jaytiss, koi, kuping-sensi, obodio, practiphile, pw, samreviews, silicagel, sl0the, soundcheck39, soundignity, superreview, timmyv and vortexreviews, all via squig.link.
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