Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Moondrop - Aria 2 | Sennheiser - IE 900 |
|---|---|---|
| Impedance | 32 Ω | 16 Ω |
| Sensitivity | 122 dB | 123 dB |
Between the Aria 2 and IE 900, the Aria 2 comes out ahead in several specs, while the IE 900 wins on impedance / sensitivity. Overall, the Aria 2 scores 65.4 and the IE 900 scores 66.4 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (65.4 vs 66.4). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.
The Aria 2 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 IE 900 if you care most about impedance / sensitivity. Its strongest claims are impedance, sensitivity. The single most decisive one: Impedance — 16.00 Ω less. 16 vs 32.
Both ship with comparable driver count, detachable cable, so those specs do not 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 says both are well-rounded; the differences are about trade-offs, not quality.
Which should you buy: Moondrop - Aria 2 or Sennheiser - IE 900?
Sennheiser - IE 900 leads the current Mars Score by 1.0 points.The more useful decision is the trade-off behind that result: compare impedance, sensitivity against the way you will actually use the product.
Choose Moondrop - Aria 2 if…
Moondrop - Aria 2 does not lead a decisive measured field here, so choose it for price, ecosystem, design, or availability when those matter more to you.
Choose Sennheiser - IE 900 if…
Sennheiser - IE 900 has the measurable edge on impedance ohm, sensitivity db.
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 Moondrop - Aria 2 wins
- No decisive advantages.
Why Sennheiser - IE 900 wins
- ▲Impedance — 16.00 Ω less. 16 vs 32.
- ▲Sensitivity — 0.82% more. 123 dB vs 122 dB.
Spec comparison
Drivers
| Spec | Moondrop - Aria 2 | Sennheiser - IE 900 |
|---|---|---|
| Driver count | 1 | 1 |
| Driver types | Dynamic | Dynamic (X3R) |
| Impedanceⓘ | 32 Ω | 16 Ωlead |
| Sensitivityⓘ | 122 dB | 123 dBlead |
Build
| Spec | Moondrop - Aria 2 | Sennheiser - IE 900 |
|---|---|---|
| Detachable cable | true | true |
| Connector | 0.78mm 2-pinlead | MMCX |