The Audio-Technica ATH-R70X is 470Ω at 98.0 dB/mW; the Meze Empyrean is 32Ω at 100.0 dB (no figure from the maker at all). 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 Audio-Technica ATH-R70X needs 2.0 dB more than the Meze Empyrean to reach the same loudness — 1.6 mW against 1.0 mW.
| Specification | Audio-Technica ATH-R70X | Meze Empyrean |
|---|---|---|
| Impedance | 470 Ω | 32 Ω |
| Sensitivity | 98.0 dB/mW | 100.0 dB |
| Sensitivity (voltage) | 101.3 dB/V | 114.9 dB/V |
| Power for 100 dB | 1.6 mW | 1.0 mW |
| Voltage for 100 dB | 0.86 V | 0.18 V |
| Current for 100 dB | 1.8 mA | 5.6 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 58.75 Ω | 4.00 Ω |
| Sources that reach 100 dB out of 280 | 277 | 280 |
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 Audio-Technica ATH-R70X — Apple USB-C dongle (EU), Steinberg UR22C, Sony NW-A306.
33 sources are low enough in output impedance for the Audio-Technica ATH-R70X under the one-eighth rule but not for the Meze Empyrean (Zoom AMS-22, Audient EVO 4, ART HeadAmp 4 Pro, 30 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: Audio-Technica ATH-R70X and Meze Empyrean. Each figure on this page is labelled on those pages with where it came from, including the ones Audio-Technica and Meze never published — what Audio-Technica publishes and what Meze publishes, both counted.