Between the IER-Z1R and Monarch MKIII, the IER-Z1R comes out ahead in several specs, while the Monarch MKIII wins on impedance / sensitivity. Overall, the IER-Z1R scores 50.3 and the Monarch MKIII scores 72.9 on our Mars Score.
Which should you buy?
The Monarch MKIII is the clear pick on raw spec strength, leading by 22.6 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.
The IER-Z1R does not pull ahead on any single popular-comparison spec — its strengths sit in the spec-table groups rather than the headline advantages.
Pick the Monarch MKIII if you care most about impedance / sensitivity. Its strongest claims are impedance, sensitivity, driver count.
Both ship with comparable detachable cable, so those specs do not separate the two — focus on the differences below.
Bottom line: the Monarch MKIII is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Sony - IER-Z1R wins
- No decisive advantages.
Why ThieAudio - Monarch MKIII wins
- ▲Impedance — 18.00 Ω less. 22 vs 40.
- ▲Sensitivity — 8.74% more. 112 dB vs 103 dB.
- ▲Driver count — 7.00 more. 10 vs 3.
Spec comparison
Drivers
| Spec | Sony - IER-Z1R | ThieAudio - Monarch MKIII |
|---|---|---|
| Driver count | 3 | 10lead |
| Driver types | 2 Dynamic + 1 Balanced Armature | 1DD + 6BA + 2EST + 1 Bone Conduction Tribrid |
| Impedanceⓘ | 40 Ω | 22 Ωlead |
| Sensitivityⓘ | 103 dB | 112 dBlead |
Build
| Spec | Sony - IER-Z1R | ThieAudio - Monarch MKIII |
|---|---|---|
| Detachable cable | true | true |
| Connector | MMCX | 2-pinlead |
Spec-level deep dives
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