Short answer: the KZ ZST X. It ranks #849 of 1369 in-ear headphones by sound quality, rated 3.5/5, at $6.99; the TRN TA4 ranks #905, rated 3.4/5, at $6. The price gap is small enough that the sound-quality ranking should decide it.
What the KZ ZST X does well: A broadly balanced tuning with a preference score of 67 against the Harman target. The tradeoff: An uneven response, 2.5 dB standard deviation from target.
What the TRN TA4 does well: A broadly balanced tuning with a preference score of 66 against the Harman target. The tradeoff: Treble about 3 dB below target from 3 to 10 kHz, which can sound dull or veiled next to brighter headphones.
Buy the KZ ZST X. It is rated higher for sound quality, and saving $0.99 with the TRN TA4 does not make up for the sound-quality gap.
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A broadly balanced tuning with a preference score of 67 against the Harman target.
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A broadly balanced tuning with a preference score of 66 against the Harman target.
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Specifications Side By Side
| KZ ZST X | TRN TA4 | |
|---|---|---|
| Price | 6.99 | 6.00 |
| Ranked | #849 of 1369 in In-Ear Headphones | #905 of 1369 in In-Ear Headphones |
| Form Factor | In-ear | In-ear |
| Back | Closed | Closed |
| Harman Preference Score | 67 (median of 8 squig.link measurements, calibrated to AutoEQ) | 66 (median of 4 squig.link measurements, calibrated to AutoEQ) |
| Deviation From Target | 2.46 dB standard deviation | 2.82 dB standard deviation |
| Tonal Tilt | -0.45 (negative is warmer, positive brighter) | -0.21 (negative is warmer, positive brighter) |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+0.4 dB at 30 Hz) | Within 6 dB of target down to 20 Hz (-3.8 dB at 30 Hz) |
| Driver Type | Hybrid | Hybrid |
| Drivers | 1 dynamic driver + 1 balanced armature (10mm dynamic + 30095 balanced armature) | 2 dynamic drivers + 2 balanced armatures (10mm beryllium DD + 6mm titanium DD + dual Knowles 33518 BA) |
| Impedance | 12 ohms | 20 ohms |
| Sensitivity | 107 dB/mW | 105 dB |
| Frequency Response | 20Hz - 40kHz | 20Hz - 40kHz |
| Weight | 0 lbs (22 g) | - |
| Connection | Wired | Wired |
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 ZST X from achoreviews, aftersound, bukanaudiophile, eplv, hbb, melatonin, pw and vortexreviews; the TRN TA4 from arn, eplv, ianfann and tonedeafmonk, all via squig.link.
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