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 covers what they ask of an amplifier, not how they sound.
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.
The Armature Art 24 is more demanding than 37% of the 567 non-electrostatic models in this database; the Aria 2 than 25%.
| dB SPL | Aria 2 power | Aria 2 voltage | Armature Art 24 power | Armature Art 24 voltage |
|---|---|---|---|---|
| 80 | 1.9 µW | 8 mV | 0.02 mW | 11 mV |
| 85 | 6.0 µW | 14 mV | 0.07 mW | 20 mV |
| 90 | 0.02 mW | 25 mV | 0.22 mW | 36 mV |
| 95 | 0.06 mW | 45 mV | 0.69 mW | 63 mV |
| 100 | 0.19 mW | 79 mV | 2.2 mW | 0.11 V |
| 105 | 0.60 mW | 0.14 V | 6.9 mW | 0.20 V |
| Source | Price | Headroom, Aria 2 | Headroom, Armature Art 24 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 21.8 dB | 4.0 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 30.1 dB | 16.1 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 27.1 dB | 13.0 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 279 reach 100 dB on both. 41 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.
The cheapest of the 41 is the JadeAudio JA11, at $20. It leaves 21.8 dB of headroom on the Aria 2 and 4.0 dB on the Armature Art 24, its output impedance is 0.5 Ω against a one-eighth limit of 4.12 Ω and 0.72 Ω, and its noise figure puts the hiss floor 13 dB and 16 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| Aria 2 | 16Hz - 22kHz (IEC61094, Free Field) | not printed | IEC61094 (free field) |
| 20Hz - 20kHz (IEC60318-4, -3dB) | -3 dB | IEC60318-4 | |
| Armature Art 24 | 7Hz-35kHz | not printed | not printed |
| 20Hz-20kHz (IEC60318-4, -3dB) | -3 dB | IEC60318-4 |
Moondrop prints two ranges, “16Hz - 22kHz (IEC61094, Free Field)” and “20Hz - 20kHz (IEC60318-4, -3dB)”, for the Aria 2 and two ranges, “7Hz-35kHz” and “20Hz-20kHz (IEC60318-4, -3dB)”, for the Armature Art 24.
Both sheets print a tolerance, which is rare enough to be worth pointing at: only 58 of the 490 models with a printed range do. These two ranges can be set against each other, because each of them says how far down the response is allowed to be at the ends.
Not a measurement; maker by maker.
Both have a page of their own. In full: 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.