The Dan Clark Audio E3 is 27Ω at 90.0 dB/mW; the Dan Clark Audio Expanse is 26Ω at 90.0 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.
In amplifier terms these two are the same headphone. The gap between what they need for 100 dB is under half a decibel, which is smaller than the step between two clicks of most volume controls.
| Specification | E3 | Expanse |
|---|---|---|
| Impedance | 27 Ω | 26 Ω |
| Sensitivity | 90.0 dB/mW | 90.0 dB/mW |
| Sensitivity (voltage) | 105.7 dB/V | 105.9 dB/V |
| Power for 100 dB | 10 mW | 10 mW |
| Voltage for 100 dB | 0.52 V | 0.51 V |
| Current for 100 dB | 19.2 mA | 19.6 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 3.38 Ω | 3.25 Ω |
| Sources that reach 100 dB out of 280 | 280 | 279 |
1 of the 280 sources has the power for the E3 but not for the Expanse — Steinberg UR22C.
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: Dan Clark Audio E3 and Dan Clark Audio Expanse. Every figure on this page comes from what Dan Clark Audio published, or is derived from it — what that maker publishes, counted.