The KZ ZST X ranks #849 out of 1369 total In-Ear Headphones for sound quality. See all Headphones rankings for every top pick.
Brand: KZ
Prices 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.
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#849 KZ ZST X: 6.99 Amazon eBay
Older model: the KZ ZST (ranked higher, rated 3.7/5). See every KZ ZST generation.
Pros: A broadly balanced tuning with a preference score of 67 against the Harman target.
Cons: An uneven response, 2.5 dB standard deviation from target.
Is the KZ ZST X right for you?
Buy it if
- you want sub-bass rumble that reaches down to 20 Hz.
- you are happy to use EQ: our preset lifts its Harman match by about 19 points.
| Back | Closed |
|---|---|
| Connection | Wired |
| Deviation From Target | 2.46 dB standard deviation |
| Driver Type | Hybrid |
| Drivers | 1 dynamic driver + 1 balanced armature (10mm dynamic + 30095 balanced armature) |
| Form Factor | In-ear |
| Frequency Response | 20Hz - 40kHz |
| Harman Preference Score | 67 (median of 8 squig.link measurements, calibrated to AutoEQ) |
| Impedance | 12 ohms |
| Sensitivity | 107 dB/mW |
| Sub-bass Extension | Within 6 dB of target down to 20 Hz (+0.4 dB at 30 Hz) |
| Tonal Tilt | -0.45 (negative is warmer, positive brighter) |
| Weight | 0 lbs (22 g) |
EQ Presets
Harman target
Set a preamp of -5.8 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 8 squig.link measurements, in the filter layout AutoEQ uses. Predicted Harman match with this EQ: 86 out of 100, up from 67.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -0.9 dB | 0.70 |
| High shelf | 10,000 Hz | -4.5 dB | 0.70 |
| Peak | 166 Hz | -4.3 dB | 0.84 |
| Peak | 1,901 Hz | -3.5 dB | 4.13 |
| Peak | 3,400 Hz | +6.0 dB | 3.18 |
| Peak | 4,913 Hz | -1.9 dB | 6.00 |
Neutral target
Set a preamp of -5.9 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 8 squig.link measurements, in the filter layout AutoEQ uses. Predicted Neutral match with this EQ: 88 out of 100, up from 33.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -9.4 dB | 0.70 |
| High shelf | 10,000 Hz | -4.5 dB | 0.70 |
| Peak | 164 Hz | -4.2 dB | 0.74 |
| Peak | 749 Hz | +1.9 dB | 1.83 |
| Peak | 1,903 Hz | -3.5 dB | 4.18 |
| Peak | 3,400 Hz | +6.0 dB | 3.17 |
| Peak | 4,913 Hz | -1.9 dB | 6.00 |
Studio flat target
Set a preamp of -6.8 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 8 squig.link measurements, in the filter layout AutoEQ uses. Predicted Studio flat match with this EQ: 92 out of 100, up from 15.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -11.9 dB | 0.70 |
| High shelf | 10,000 Hz | +1.3 dB | 0.70 |
| Peak | 168 Hz | -6.1 dB | 0.77 |
| Peak | 766 Hz | +1.8 dB | 2.27 |
| Peak | 1,857 Hz | -2.7 dB | 4.97 |
| Peak | 2,645 Hz | +2.2 dB | 6.00 |
| Peak | 3,148 Hz | +6.0 dB | 2.69 |
| Peak | 3,758 Hz | +3.1 dB | 6.00 |
| Peak | 5,002 Hz | -4.1 dB | 6.00 |
| Peak | 7,957 Hz | -2.1 dB | 6.00 |
Warm target
Set a preamp of -5.7 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 8 squig.link measurements, in the filter layout AutoEQ uses. Predicted Warm match with this EQ: 88 out of 100, up from 71.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -0.6 dB | 0.70 |
| High shelf | 10,000 Hz | -6.0 dB | 0.70 |
| Peak | 164 Hz | -4.1 dB | 0.86 |
| Peak | 759 Hz | +2.1 dB | 1.98 |
| Peak | 1,911 Hz | -4.0 dB | 4.04 |
| Peak | 2,821 Hz | +1.5 dB | 6.00 |
| Peak | 3,341 Hz | +5.3 dB | 5.18 |
| Peak | 3,880 Hz | +2.3 dB | 5.89 |
| Peak | 4,997 Hz | -4.5 dB | 6.00 |
| Peak | 7,759 Hz | -3.9 dB | 6.00 |
Bass target
Set a preamp of -5.8 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 8 squig.link measurements, in the filter layout AutoEQ uses. Predicted Bass match with this EQ: 87 out of 100, up from 68.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +2.9 dB | 0.70 |
| High shelf | 10,000 Hz | -4.5 dB | 0.70 |
| Peak | 170 Hz | -4.3 dB | 0.87 |
| Peak | 1,901 Hz | -3.5 dB | 4.12 |
| Peak | 3,400 Hz | +6.0 dB | 3.18 |
| Peak | 4,913 Hz | -1.9 dB | 6.00 |
Bright target
Set a preamp of -6.4 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 8 squig.link measurements, in the filter layout AutoEQ uses. Predicted Bright match with this EQ: 89 out of 100, up from 24.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | -9.4 dB | 0.70 |
| High shelf | 10,000 Hz | -0.6 dB | 0.70 |
| Peak | 164 Hz | -4.3 dB | 0.72 |
| Peak | 738 Hz | +1.8 dB | 2.05 |
| Peak | 1,903 Hz | -3.7 dB | 3.94 |
| Peak | 2,923 Hz | +2.4 dB | 6.00 |
| Peak | 3,628 Hz | +6.0 dB | 1.90 |
| Peak | 6,002 Hz | +3.9 dB | 6.00 |
V-shaped target
Set a preamp of -6.3 dB, then add these filters in any parametric equalizer (Wavelet, Equalizer APO, Peace, or a player with parametric EQ). Calculated by Speaker Ranking from the median of 8 squig.link measurements, in the filter layout AutoEQ uses. Predicted V-shaped match with this EQ: 86 out of 100, up from 67.
| Filter | Frequency | Gain | Q |
|---|---|---|---|
| Low shelf | 105 Hz | +3.6 dB | 0.70 |
| High shelf | 10,000 Hz | +0.8 dB | 0.70 |
| Peak | 164 Hz | -3.0 dB | 0.95 |
| Peak | 1,880 Hz | -3.6 dB | 3.21 |
| Peak | 3,354 Hz | +6.0 dB | 1.81 |
| Peak | 4,018 Hz | +1.9 dB | 6.00 |
| Peak | 5,919 Hz | +4.6 dB | 6.00 |
- Reviews, Comparisons and Sound Samples
Frequency Response
How the KZ ZST X measures across the audible range, against the Harman in-ear target that most listeners prefer in blind tests. Where the line sits above the target that range sounds louder (more bass, brighter treble), below it quieter. The curve is the median of 8 independent measurements, so one odd sample or rig cannot skew it, and both lines are shifted so their 500 Hz to 2 kHz average sits at 0 dB.
Measurement data: median of 8 measurements from the squig.link databases of achoreviews, aftersound, bukanaudiophile, eplv, hbb, melatonin, pw and vortexreviews. Thanks to each of them for publishing their work.
Head-to-Head Comparisons
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