The Audio-Technica ATH-ADX5000 is 420Ω at 100.0 dB/mW; the Audio-Technica ATH-R70X is 470Ω at 98.0 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 ATH-R70X needs 2.0 dB more than the ATH-ADX5000 to reach the same loudness — 1.6 mW against 1.0 mW.
| Specification | ATH-ADX5000 | ATH-R70X |
|---|---|---|
| Impedance | 420 Ω | 470 Ω |
| Sensitivity | 100.0 dB/mW | 98.0 dB/mW |
| Sensitivity (voltage) | 103.8 dB/V | 101.3 dB/V |
| Power for 100 dB | 1.0 mW | 1.6 mW |
| Voltage for 100 dB | 0.65 V | 0.86 V |
| Current for 100 dB | 1.5 mA | 1.8 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 52.50 Ω | 58.75 Ω |
| Sources that reach 100 dB out of 280 | 280 | 277 |
3 of the 280 sources have the power for the ATH-ADX5000 but not for the ATH-R70X — Apple USB-C dongle (EU), Steinberg UR22C, Sony NW-A306.
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-ADX5000 and Audio-Technica ATH-R70X. Every figure on this page comes from what Audio-Technica published, or is derived from it — what that maker publishes, counted.