Short answer: the FiiO FH9. It ranks #594 of 1291 in-ear headphones by sound quality, rated 3.8/5, at $559.99. The FiiO FD5 ranks #631, rated 3.7/5, at $495.27, $64.72 cheaper, which does not close the gap in sound quality.
Why pick the FiiO FH9: A hybrid flagship with a 13.6mm DLC dynamic driver and six Knowles balanced armatures. The catch: A 2.35 dB spread from the target shows peaks and dips that better tuned sets avoid.
The case for the FiiO FD5: A warm, punchy 12mm dynamic in-ear with a preference score of 70, bass about 4 dB above target and flat sub-bass to 20 Hz. Watch for: The bass boost spills into the low mids by about 2 dB, which can thicken male vocals and make dense mixes sound slightly congested.
Buy the FiiO FH9. It is rated higher for sound quality, and the $64.72 you would save on the FiiO FD5 does not close the gap.
Looking for alternatives? See the complete Headphones rankings.
A hybrid flagship with a 13.6mm DLC dynamic driver and six Knowles balanced armatures.
Amazon $559.99 eBay
A warm, punchy 12mm dynamic in-ear with a preference score of 70, bass about 4 dB above target and flat sub-bass to 20 Hz.
Amazon $495.27 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
| FiiO FH9 | FiiO FD5 | |
|---|---|---|
| Price | $559.99 | $495.27 |
| Ranked | #594 of 1291 in In-Ear Headphones | #631 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Connection | Wired | Wired |
| Driver Type | Hybrid | Dynamic |
| Drivers | 1 x 13.6mm dynamic + 6 x Knowles balanced armature | 1 x 12mm dynamic |
| Impedance | 18 ohms | 32 ohms |
| Sensitivity | 108 dB/mW | 109 dB/mW |
| Harman Preference Score | 71 (median of 3 squig.link measurements, calibrated to AutoEQ) | 70 (measured by crinacle, via AutoEQ) |
| Deviation From Target | 2.35 dB standard deviation | 2.40 dB standard deviation |
| Tonal Tilt | -0.14 (negative is warmer, positive brighter) | -0.45 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-2.2 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-0.4 dB at 30 Hz) |
| Weight | - | 0 lbs (11 g) per earbud |
| Frequency Response | - | 10Hz - 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 FiiO FH9 from ekaudio, jaytiss and therollo9; the FiiO FD5 from dchpgall, hbb, jaytiss, precog, recode, rg and superreview, all via squig.link.
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