Short answer: the KZ EDX Ultra. It ranks #877 of 1369 in-ear headphones by sound quality, rated 3.4/5, at $24.99; the CCA Hydro ranks #960, rated 3.3/5, at $24.99. The price gap is small enough that the sound-quality ranking should decide it.
The case for the KZ EDX Ultra: Bass is lifted about 3.2 dB with extension to 20 Hz, giving kick drums and bass lines extra weight. The tradeoff: Presence sits about 3.1 dB low with a 6.8 dB dip near 6.7 kHz, so vocals and instruments lose some bite.
Why pick the CCA Hydro: About 3 dB more bass than the Harman target below 150 Hz, for listeners who want a fuller low end. The catch: An uneven response, 2.5 dB standard deviation from target.
Buy the KZ EDX Ultra. It is rated higher for sound quality than the CCA Hydro at the same price, which makes it the one to get unless you need something the other one does better.
Want more options? Browse the full Headphones rankings.
Bass is lifted about 3.2 dB with extension to 20 Hz, giving kick drums and bass lines extra weight.
Amazon $24.99 eBay
About 3 dB more bass than the Harman target below 150 Hz, for listeners who want a fuller low end.
Linsoul eBayPrices on this page were last checked October 17, 2026 at 6:04 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
| KZ EDX Ultra | CCA Hydro | |
|---|---|---|
| Price | $24.99 | 24.99 |
| Ranked | #877 of 1369 in In-Ear Headphones | #960 of 1369 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Connection | Wired | Wired |
| Driver Type | Dynamic | Hybrid |
| Drivers | 1 x 10mm dynamic | 10 drivers (2 dynamic drivers + 8 balanced armatures) |
| Impedance | 26 ohms | 15-20 ohms |
| Frequency Response | 20Hz - 40kHz (Manufacturer specified) | 20Hz - 40kHz |
| Harman Preference Score | 66 (median of 13 squig.link measurements, calibrated to AutoEQ) | 65 (median of 4 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.40 dB standard deviation | 2.54 dB standard deviation |
| Tonal Tilt | -0.75 (negative is warmer, positive brighter) | -0.37 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+0.0 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (+0.3 dB at 30 Hz) |
| Sensitivity | - | 102 dB |
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 EDX Ultra from aftersound, ankramutt, bassyalexander, harpo, ianfann, jacstone, lown-fi, precog, pw, rg, soundcheck39, soundignity and vortexreviews; the CCA Hydro from audioamigo, obodio, pw and superreview, all via squig.link.
Related Headphone Comparisons
How KZ EDX Ultra compares with other leading options: