The Moondrop Aria 2 is 33Ω at 107.2 dB/mW; the Moondrop Armature Art 24 is 5.8Ω at 96.6 dB/mW. This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.
The Armature Art 24 needs 10.6 dB more than the Aria 2 to reach the same loudness — 2.2 mW against 0.19 mW.
| Specification | Aria 2 | Armature Art 24 |
|---|---|---|
| Impedance | 33 Ω | 5.8 Ω |
| Sensitivity | 107.2 dB/mW | 96.6 dB/mW |
| Sensitivity (voltage) | 122.0 dB/V | 119.0 dB/V |
| Power for 100 dB | 0.19 mW | 2.2 mW |
| Voltage for 100 dB | 79 mV | 0.11 V |
| Current for 100 dB | 2.4 mA | 19.4 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.12 Ω | 0.72 Ω |
| Sources that reach 100 dB out of 280 | 280 | 279 |
1 of the 280 sources has the power for the Aria 2 but not for the Armature Art 24 — Steinberg UR22C.
49 sources are low enough in output impedance for the Aria 2 under the one-eighth rule but not for the Armature Art 24 (FiiO SnowSky Tiny B, FiiO KA13, FiiO KA15, 46 more).
2 sources stay below the audible-hiss threshold with the Armature Art 24 but cross it with the Aria 2 (FiiO BTR11, Rupert Neve RNHP).
279 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.
Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Moondrop Aria 2 and Moondrop Armature Art 24. Every figure on this page comes from what Moondrop published, or is derived from it — what that maker publishes, counted.