Short answer: the 7Hz Elua Ultra. It ranks #208 of 1291 in-ear headphones by sound quality, rated 4.3/5, at $31.49; the KZ D-Fi ranks #289, rated 4.2/5, and costs $32.99, which makes this an easy call rather than a real tradeoff.
What the 7Hz Elua Ultra does well: The median of 11 hobbyist measurements gives it a very good Harman preference score of 77 with a 1.42 dB spread, and its mids sit within about 0.5 dB of target, so vocals and instruments sound natural. The catch: A 4.1 dB peak near 11.9 kHz can make cymbals and sibilance sound sharp.
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. Watch for: 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.
Buy the 7Hz Elua Ultra. It is rated higher for sound quality than the KZ D-Fi and costs less, so only choose the other one for a particular feature it does better.
Want more options? Browse the full Headphones rankings.
The median of 11 hobbyist measurements gives it a very good Harman preference score of 77 with a 1.42 dB spread, and its mids sit within about 0.5 dB of target, so vocals and instruments sound natural.
Amazon $31.49 eBay
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 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.
As an eBay Partner, we may be compensated if you make a purchase.
Specifications Side By Side
| 7Hz Elua Ultra | KZ D-Fi | |
|---|---|---|
| Price | $31.49 | $32.99 |
| Ranked | #208 of 1291 in In-Ear Headphones | #289 of 1291 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 77 (median of 11 squig.link measurements, calibrated to AutoEQ) | 76 (median of 23 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 1.42 dB standard deviation | 1.85 dB standard deviation |
| Tonal Tilt | -0.64 (negative is warmer, positive brighter) | -0.25 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+2.3 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-2.1 dB at 30 Hz) |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Dynamic |
| Drivers | 1 x 10mm dynamic + 1 x 8mm dynamic | 1 x 10mm dual-magnet dynamic |
| Impedance | 19 ohms | 23.5 ohms |
| Sensitivity | 108 dB/V | - |
| Frequency Response | 10Hz - 20kHz (Manufacturer specified) | 7Hz - 45kHz (Manufacturer specified) |
| Built-in Microphone | 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 7Hz Elua Ultra from aftersound, atechreviews, audioamigo, bassaudio, csi-zone, ducbloke, jaytiss, pw, soundcheck39, soundignity and vortexreviews; 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, all via squig.link.
Related Headphone Comparisons
How 7Hz Elua Ultra compares with other leading options: