Short answer: the 7Hz Salnotes Zero. It ranks #26 of 1291 in-ear headphones by sound quality, rated 4.8/5, at $22.99; the Aoshida E20 ranks #40, rated 4.7/5, at $22.99. The price gap is small enough that the sound-quality ranking should decide it.
Why pick the 7Hz Salnotes Zero: A Harman score of 84 from a single 10 mm dynamic driver at a bargain price is remarkable. The catch: Presence and treble run about 2.1 to 2.2 dB under target, and a 6.2 dB dip near 10 kHz leaves cymbals and breath detail muted.
The case for the Aoshida E20: Across six hobbyist measurements on squig.link, the E20 reaches a preference score of 82.6 with a smooth 1.13 dB deviation from target. The tradeoff: A 6 dB peak near 8.4 kHz and treble about 2.1 dB above target from 6 to 10 kHz can make sibilance and hi hats sound sharp on bright recordings.
Buy the 7Hz Salnotes Zero. It is rated higher for sound quality than the Aoshida E20 at the same price, so it is the default pick unless a specific strength of the other one matters more to you.
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A Harman score of 84 from a single 10 mm dynamic driver at a bargain price is remarkable.
Amazon $22.99 eBay
Across six hobbyist measurements on squig.link, the E20 reaches a preference score of 82.6 with a smooth 1.13 dB deviation from target.
Amazon $22.99 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
| 7Hz Salnotes Zero | Aoshida E20 | |
|---|---|---|
| Price | $22.99 | $22.99 |
| Ranked | #26 of 1291 in In-Ear Headphones | #40 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Harman Preference Score | 84 (measured by oratory1990, via AutoEQ) | 83 (median of 6 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 1.31 dB standard deviation | 1.13 dB standard deviation |
| Tonal Tilt | -0.16 (negative is warmer, positive brighter) | +0.26 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-1.4 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-0.8 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Dynamic |
| Drivers | 1 x 10mm dynamic | 1 x 10mm dynamic + 1 x 8mm dynamic |
| Impedance | 32 ohms | 12 ohms |
| Sensitivity | 108 dB SPL/V | 98 dB |
| Frequency Response | 10Hz - 20kHz (Manufacturer specified) | 20Hz - 40kHz (Manufacturer specified) |
| Back | Closed | Closed |
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 7Hz Salnotes Zero from achoreviews, aftersound, ankramutt, arn, audioamigo, bassaudio, bedrock, cammyfi, dentreviews, dvewlsh, eplv, flare, gadgetrytech, harpo, harutohiroki, hbb, hobbytalk, ianfann, iemocean, iemworld, jaytiss, lown-fi, lumerion, mmagtech, musicafe, nymz, precog, pw, sl0the, soundcheck39, superreview, tedthepraimortis, theaudiostore, therollo9, timmyv, treblewellxtended, vortexreviews and yoshiultra; the Aoshida E20 from audioamigo, boizoff, harpo, jacstone, soundcheck39 and tonedeafmonk, all via squig.link.
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