The Audeze LCD-4 is 200Ω at 97.0 dB/mW; the Audeze LCD-5 is 14Ω 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 LCD-5 needs 7.0 dB more than the LCD-4 to reach the same loudness — 10 mW against 2.0 mW.
| Specification | LCD-4 | LCD-5 |
|---|---|---|
| Impedance | 200 Ω | 14 Ω |
| Sensitivity | 97.0 dB/mW | 90.0 dB/mW |
| Sensitivity (voltage) | 104.0 dB/V | 108.5 dB/V |
| Power for 100 dB | 2.0 mW | 10 mW |
| Voltage for 100 dB | 0.63 V | 0.37 V |
| Current for 100 dB | 3.2 mA | 26.7 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 25.00 Ω | 1.75 Ω |
| Sources that reach 100 dB out of 280 | 280 | 274 |
6 of the 280 sources have the power for the LCD-4 but not for the LCD-5 — Apple USB-C dongle (EU), Zoom AMS-22, Steinberg UR22C, 3 more.
23 sources are low enough in output impedance for the LCD-4 under the one-eighth rule but not for the LCD-5 (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 20 more).
274 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 LCD-4 and Audeze LCD-5. Every figure on this page comes from what Audeze published, or is derived from it — what that maker publishes, counted.