The Focal Clear is 55Ω at 104.0 dB/mW; the Focal Lensys Professional is 26Ω at 100.0 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 Lensys Professional needs 4.0 dB more than the Clear to reach the same loudness — 1.0 mW against 0.40 mW.
| Specification | Clear | Lensys Professional |
|---|---|---|
| Impedance | 55 Ω | 26 Ω |
| Sensitivity | 104.0 dB/mW | 100.0 dB/mW |
| Sensitivity (voltage) | 116.6 dB/V | 115.9 dB/V |
| Power for 100 dB | 0.40 mW | 1.0 mW |
| Voltage for 100 dB | 0.15 V | 0.16 V |
| Current for 100 dB | 2.7 mA | 6.2 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 6.88 Ω | 3.25 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.
1 source is low enough in output impedance for the Clear under the one-eighth rule but not for the Lensys Professional (Shanling H5).
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: Focal Clear and Focal Lensys Professional. Every figure on this page comes from what Focal published, or is derived from it — what that maker publishes, counted.