The Audeze Euclid is 12Ω at 105.0 dB/mW; the Audeze LCD-i3 is 20Ω at 110.0 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 Euclid needs 5.0 dB more than the LCD-i3 to reach the same loudness — 0.32 mW against 0.10 mW.
| Specification | Euclid | LCD-i3 |
|---|---|---|
| Impedance | 12 Ω | 20 Ω |
| Sensitivity | 105.0 dB/mW | 110.0 dB/mW |
| Sensitivity (voltage) | 124.2 dB/V | 127.0 dB/V |
| Power for 100 dB | 0.32 mW | 0.10 mW |
| Voltage for 100 dB | 62 mV | 45 mV |
| Current for 100 dB | 5.1 mA | 2.2 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 1.50 Ω | 2.50 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
Every source in the database that drives one of them drives the other. On power, the choice between these two changes nothing about what amplifier you need.
5 sources are low enough in output impedance for the LCD-i3 under the one-eighth rule but not for the Euclid (FiiO KA13, Schiit Vali 2+, Astell&Kern HC3, 2 more).
10 sources stay below the audible-hiss threshold with the Euclid but cross it with the LCD-i3 (Lake People G103-S Mk II, Grace Design m900, FiiO M33 R2R, 7 more).
280 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: Audeze Euclid and Audeze LCD-i3. Every figure on this page comes from what Audeze published, or is derived from it — what that maker publishes, counted.