Between the ZAR and IER-M9, the ZAR comes out ahead in sensitivity and driver count, while the IER-M9 wins on impedance. Overall, the ZAR scores 65.4 and the IER-M9 scores 54.5 on our Mars Score.
Which should you buy?
The ZAR is the clear pick on raw spec strength, leading by 10.9 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the ZAR if you care most about sensitivity and driver count. The biggest gaps in its favor are sensitivity, driver count.
Pick the IER-M9 if you care most about impedance. Its strongest claims are impedance.
Both ship with comparable detachable cable, so those specs don't separate the two — focus on the differences below.
Bottom line: the ZAR is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why KZ - ZAR wins
- ▲Sensitivity — 4.85% more. 108 dB vs 103 dB.
- ▲Driver count — 3.00 more. 8 vs 5.
Why Sony - IER-M9 wins
- ▲Impedance — 8.00 Ω less. 18 vs 26.
Spec comparison
Drivers
| Spec | KZ - ZAR | Sony - IER-M9 |
|---|---|---|
| Driver count | 8lead | 5 |
| Driver types | 1DD + 7BA Hybrid | 5 Balanced Armature |
| Impedanceⓘ | 26 Ω | 18 Ωlead |
| Sensitivityⓘ | 108 dBlead | 103 dB |
Build
| Spec | KZ - ZAR | Sony - IER-M9 |
|---|---|---|
| Detachable cable | true | true |
| Connector | 0.78mm 2-pinlead | MMCX |
Frequently asked
Spec-level deep dives
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