Short answer: the KZ D-Fi. It ranks #289 of 1291 in-ear headphones by sound quality, rated 4.2/5, at $32.99; the NF Audio RA05 ranks #372, rated 4.1/5, at $31.99. The price gap is small enough that the sound-quality ranking should decide it.
What the KZ D-Fi does well: Remarkably well tuned for the money: the median of 23 measurements has a 1.85 dB spread and a Harman preference score of 76, with bass, lower mids and upper mids all within about 1 dB of target. The tradeoff: Presence sits about 3 dB low with a 6 dB dip near 5.9 kHz, so voices can sound a touch distant and treble a little dull.
The case for the NF Audio RA05: The median of 12 hobbyist measurements gives it a solid Harman preference score of 74 with a 1.89 dB spread. Watch for: A 6.9 dB peak near 8.6 kHz can make cymbals and sibilance sound sharp.
Buy the KZ D-Fi. It is rated higher for sound quality, and the $1 you would save on the NF Audio RA05 does not close the gap.
Looking for alternatives? See the complete Headphones rankings.
Remarkably well tuned for the money: the median of 23 measurements has a 1.85 dB spread and a Harman preference score of 76, with bass, lower mids and upper mids all within about 1 dB of target.
Amazon $32.99 eBay
The median of 12 hobbyist measurements gives it a solid Harman preference score of 74 with a 1.89 dB spread.
NF Acous $31.99 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
| KZ D-Fi | NF Audio RA05 | |
|---|---|---|
| Price | $32.99 | $31.99 |
| Ranked | #289 of 1291 in In-Ear Headphones | #372 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Dynamic |
| Drivers | 1 x 10mm dual-magnet dynamic | 1 x 6mm dynamic |
| Impedance | 23.5 ohms | 16 ohms |
| Frequency Response | 7Hz - 45kHz (Manufacturer specified) | 15Hz - 30kHz (Manufacturer specified) |
| Harman Preference Score | 76 (median of 23 squig.link measurements, calibrated to AutoEQ) | 74 (median of 12 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 1.85 dB standard deviation | 1.89 dB standard deviation |
| Tonal Tilt | -0.25 (negative is warmer, positive brighter) | +0.41 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (-2.1 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-0.9 dB at 30 Hz) |
| Sensitivity | - | 102 dB/mW |
| Built-in Microphone | - | Yes |
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 KZ D-Fi from aden, ankramutt, arn, awsmdanny, bukanaudiophile, cammyfi, csi-zone, dchpgall, fahryst, flare, gadgetrytech, hoods, jaraba, kazi, musicafe, obodio, pw, recode, sl0the, soundignity, superreview, tonedeafmonk and zerostresslevel; the NF Audio RA05 from aftersound, digaoreviews, hobbytalk, jaytiss, musicafe, obodio, practiphile, pw, suporsalad, theaudiostore, treblewellxtended and vortexreviews, all via squig.link.
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