The Meze Empyrean is 32Ω at 100.0 dB (no figure from the maker at all); the ZMF Atrium is 300Ω at 96.0 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 ZMF Atrium needs 4.0 dB more than the Meze Empyrean to reach the same loudness — 2.5 mW against 1.0 mW.
| Specification | Meze Empyrean | ZMF Atrium |
|---|---|---|
| Impedance | 32 Ω | 300 Ω |
| Sensitivity | 100.0 dB | 96.0 dB/mW |
| Sensitivity (voltage) | 114.9 dB/V | 101.2 dB/V |
| Power for 100 dB | 1.0 mW | 2.5 mW |
| Voltage for 100 dB | 0.18 V | 0.87 V |
| Current for 100 dB | 5.6 mA | 2.9 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.00 Ω | 37.50 Ω |
| Sources that reach 100 dB out of 280 | 280 | 277 |
One caution before reading the rows. For Meze Empyrean the maker publishes no sensitivity figure at all. The number in the table was collected when this database was first built and has never been traced to a manufacturer document, so treat every row below it as an estimate rather than a specification.
3 of the 280 sources have the power for the Meze Empyrean but not for the ZMF Atrium — Apple USB-C dongle (EU), Steinberg UR22C, Sony NW-A306.
20 sources are low enough in output impedance for the ZMF Atrium under the one-eighth rule but not for the Meze Empyrean (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 17 more).
277 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: Meze Empyrean and ZMF Atrium. Each figure on this page is labelled on those pages with where it came from, including the ones Meze and ZMF never published — what Meze publishes and what ZMF publishes, both counted.