Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Etymotic - ER4XR | Sony - IER-Z1R |
|---|---|---|
| Sensitivity | 98 dB | 103 dB |
| Impedance | 45 Ω | 40 Ω |
| Driver count | 1 | 3 |
Between the ER4XR and IER-Z1R, the ER4XR comes out ahead in several specs, while the IER-Z1R wins on sensitivity / impedance. Overall, the ER4XR scores 39.7 and the IER-Z1R scores 50.3 on our Mars Score.
Which should you buy?
The IER-Z1R is the clear pick on raw spec strength, leading by 10.6 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 ER4XR 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 IER-Z1R if you care most about sensitivity / impedance. Its strongest claims are sensitivity, impedance, driver count. The single most decisive one: Sensitivity — 5.10% more. 103 dB vs 98 dB.
Both ship with comparable detachable cable, so those specs do not separate the two — focus on the differences below.
Bottom line: the IER-Z1R is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Etymotic - ER4XR or Sony - IER-Z1R?
Sony - IER-Z1R leads the current Mars Score by 10.6 points.The more useful decision is the trade-off behind that result: compare driver count, impedance, sensitivity against the way you will actually use the product.
Choose Etymotic - ER4XR if…
Etymotic - ER4XR does not lead a decisive measured field here, so choose it for price, ecosystem, design, or availability when those matter more to you.
Choose Sony - IER-Z1R if…
Sony - IER-Z1R has the measurable edge on sensitivity db, impedance ohm, driver count.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Etymotic - ER4XR wins
- No decisive advantages.
Why Sony - IER-Z1R wins
- ▲Sensitivity — 5.10% more. 103 dB vs 98 dB.
- ▲Impedance — 5.00 Ω less. 40 vs 45.
- ▲Driver count — 2.00 more. 3 vs 1.
Spec comparison
Drivers
| Spec | Etymotic - ER4XR | Sony - IER-Z1R |
|---|---|---|
| Driver count | 1 | 3lead |
| Driver types | Balanced Armature | 2 Dynamic + 1 Balanced Armature |
| Impedanceⓘ | 45 Ω | 40 Ωlead |
| Sensitivityⓘ | 98 dB | 103 dBlead |
Build
| Spec | Etymotic - ER4XR | Sony - IER-Z1R |
|---|---|---|
| Detachable cable | true | true |
| Connector | MMCX | MMCX |