The Focal Elex (Drop) is 80Ω at 104.0 dB (no figure from the maker at all); the Focal Lensys Professional is 26Ω at 100.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The Lensys Professional needs 4.0 dB more than the Elex (Drop) to reach the same loudness — 1.0 mW against 0.40 mW.
| Specification | Elex (Drop) | Lensys Professional |
|---|---|---|
| Impedance | 80 Ω | 26 Ω |
| Sensitivity | 104.0 dB | 100.0 dB/mW |
| Sensitivity (voltage) | 115.0 dB/V | 115.9 dB/V |
| Power for 100 dB | 0.40 mW | 1.0 mW |
| Voltage for 100 dB | 0.18 V | 0.16 V |
| Current for 100 dB | 2.2 mA | 6.2 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 10.00 Ω | 3.25 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
One caution before reading the rows. For Focal Elex (Drop) 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.
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.
10 sources are low enough in output impedance for the Elex (Drop) under the one-eighth rule but not for the Lensys Professional (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 7 more).
280 of the 280 sources here reach 100 dB on both.
The Elex (Drop) is more demanding than 53% of the 567 non-electrostatic models in this database; the Lensys Professional than 51%.
| dB SPL | Elex (Drop) power | Elex (Drop) voltage | Lensys Professional power | Lensys Professional voltage |
|---|---|---|---|---|
| 80 | 4.0 µW | 18 mV | 0.01 mW | 16 mV |
| 85 | 0.01 mW | 32 mV | 0.03 mW | 29 mV |
| 90 | 0.04 mW | 56 mV | 0.10 mW | 51 mV |
| 95 | 0.13 mW | 0.10 V | 0.32 mW | 91 mV |
| 100 | 0.40 mW | 0.18 V | 1.0 mW | 0.16 V |
| 105 | 1.3 mW | 0.32 V | 3.2 mW | 0.29 V |
| Source | Price | Headroom, Elex (Drop) | Headroom, Lensys Professional | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 14.8 dB | 13.9 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 23.1 dB | 23.2 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR11 | $36 | 14.7 dB | 15.2 dB | 0.5 Ω | 8.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 69 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.
The cheapest of the 69 is the JadeAudio JA11, at $20. It leaves 14.8 dB of headroom on the Elex (Drop) and 13.9 dB on the Lensys Professional, its output impedance is 0.5 Ω against a one-eighth limit of 10.00 Ω and 3.25 Ω, and its noise figure puts the hiss floor 20 dB and 20 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
Both have a page of their own. In full: Focal Elex (Drop) and Focal Lensys Professional. Each figure on this page is labelled on those pages with where it came from, including the ones Focal never published — what that maker publishes, counted.