Between the IER-M9 and IER-Z1R, the IER-M9 comes out ahead in impedance and driver count, while the IER-Z1R wins on several specs. Overall, the IER-M9 scores 54.5 and the IER-Z1R scores 50.3 on our Mars Score.
Which should you buy?
The IER-M9 edges ahead on the Mars Score (54.5 vs 50.3), but the 4.2-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the IER-M9 if you care most about impedance and driver count. The biggest gaps in its favor are impedance, driver count.
The IER-Z1R similarly doesn't carry a headline advantage on the popular specs — look at the full table for category-specific deltas.
Both ship with comparable sensitivity, detachable cable, so those specs don't separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity tells you both are well-rounded; the differences are about trade-offs, not quality.
Why Sony - IER-M9 wins
- ▲Impedance — 22.00 Ω less. 18 vs 40.
- ▲Driver count — 2.00 more. 5 vs 3.
Why Sony - IER-Z1R wins
- No decisive advantages.
Spec comparison
Drivers
| Spec | Sony - IER-M9 | Sony - IER-Z1R |
|---|---|---|
| Driver count | 5lead | 3 |
| Driver types | 5 Balanced Armature | 2 Dynamic + 1 Balanced Armature |
| Impedanceⓘ | 18 Ωlead | 40 Ω |
| Sensitivityⓘ | 103 dB | 103 dB |
Build
| Spec | Sony - IER-M9 | Sony - IER-Z1R |
|---|---|---|
| Detachable cable | true | true |
| Connector | MMCX | MMCX |
Frequently asked
Spec-level deep dives
More from the same brands
vsMars is reader-supported. When you buy through links on our site, we may earn an affiliate commission at no extra cost to you. Learn more.