Short answer: a tie on sound quality. Both are rated 3.7/5 (#627 and #637 of 1291 in-ear headphones) at nearly the same price ($14.99 vs $15.99), so choose on features and fit.
What the 7Hz Aero does well: Across eight hobbyist measurements on squig.link it earns a Harman preference score of 70.6 with a smooth 1.97 dB deviation, an unusually even response for such an inexpensive single 9.2mm dynamic earphone. Watch for: The 10 to 16 kHz air region runs about 5.3 dB above target, and a 5.3 dB peak near 8.4 kHz can make cymbals and sibilance a little splashy on bright recordings.
The case for the KZ EDC Pro: Exceptional value: the median of 22 measurements scores 70 on the Harman preference scale with a 2.0 dB spread, unusually even for a budget IEM. The catch: The bass lift makes it fun rather than neutral, and a 5.6 dB peak near 12 kHz can add sparkle that edges toward sharp on bright recordings.
Buy the 7Hz Aero or the KZ EDC Pro on features: they are rated the same for sound quality at close to the same price.
Still deciding? The full Headphones rankings cover every ranked option.
Across eight hobbyist measurements on squig.link it earns a Harman preference score of 70.6 with a smooth 1.97 dB deviation, an unusually even response for such an inexpensive single 9.2mm dynamic earphone.
Amazon $14.99 eBay
Exceptional value: the median of 22 measurements scores 70 on the Harman preference scale with a 2.0 dB spread, unusually even for a budget IEM.
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Specifications Side By Side
| 7Hz Aero | KZ EDC Pro | |
|---|---|---|
| Price | $14.99 | $15.99 |
| Ranked | #627 of 1291 in In-Ear Headphones | #637 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 71 (median of 8 squig.link measurements, calibrated to AutoEQ) | 70 (median of 22 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 1.97 dB standard deviation | 2.00 dB standard deviation |
| Tonal Tilt | -0.81 (negative is warmer, positive brighter) | -0.80 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+2.8 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (+2.5 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Dynamic |
| Drivers | 1 x 9.2mm dynamic | 1 x 10mm dynamic |
| Impedance | - | 23.5 ohms |
| Frequency Response | - | 20Hz - 40kHz (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 7Hz Aero from achoreviews, aftersound, bassyalexander, musicafe, pw, silicagel, soundcheck39 and vortexreviews; the KZ EDC Pro from aftersound, ankramutt, audioamigo, banzai1122, boizoff, doltonius, ducbloke, eplv, fernandagunsan, jacstone, jaytiss, koi, kuping-sensi, lown-fi, musicafe, obodio, pw, scboy, sl0the, soundcheck39, soundignity and therollo9, all via squig.link.
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