The Dan Clark Audio Ether C Flow 1.1 is 23Ω at 94.0 dB (no figure from the maker at all); the Dan Clark Audio Noire X is 13Ω 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.
The Noire X needs 4.0 dB more than the Ether C Flow 1.1 to reach the same loudness — 10 mW against 4.0 mW.
| Specification | Ether C Flow 1.1 | Noire X |
|---|---|---|
| Impedance | 23 Ω | 13 Ω |
| Sensitivity | 94.0 dB | 90.0 dB/mW |
| Sensitivity (voltage) | 110.4 dB/V | 108.9 dB/V |
| Power for 100 dB | 4.0 mW | 10 mW |
| Voltage for 100 dB | 0.30 V | 0.36 V |
| Current for 100 dB | 13.2 mA | 27.7 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 2.88 Ω | 1.62 Ω |
| Sources that reach 100 dB out of 280 | 280 | 272 |
One caution before reading the rows. For Dan Clark Audio Ether C Flow 1.1 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.
8 of the 280 sources have the power for the Ether C Flow 1.1 but not for the Noire X — Apple USB-C dongle (EU), Zoom AMS-22, Audient EVO 4, 5 more.
5 sources are low enough in output impedance for the Ether C Flow 1.1 under the one-eighth rule but not for the Noire X (FiiO KA13, Schiit Vali 2+, Astell&Kern HC3, 2 more).
272 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 Ether C Flow 1.1 and Dan Clark Audio Noire X. Each figure on this page is labelled on those pages with where it came from, including the ones Dan Clark Audio never published — what that maker publishes, counted.