The Focal Elex (Drop) is 80Ω at 104.0 dB (no figure from the maker at all); the Focal Listen Professional is 32Ω at 107.1 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The Elex (Drop) needs 3.1 dB more than the Listen Professional to reach the same loudness — 0.40 mW against 0.19 mW.
| Specification | Elex (Drop) | Listen Professional |
|---|---|---|
| Impedance | 80 Ω | 32 Ω |
| Sensitivity | 104.0 dB | 107.1 dB/mW |
| Sensitivity (voltage) | 115.0 dB/V | 122.0 dB/V |
| Power for 100 dB | 0.40 mW | 0.19 mW |
| Voltage for 100 dB | 0.18 V | 79 mV |
| Current for 100 dB | 2.2 mA | 2.5 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 10.00 Ω | 4.00 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 Listen Professional (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 7 more).
2 sources stay below the audible-hiss threshold with the Elex (Drop) but cross it with the Listen Professional (FiiO BTR11, Rupert Neve RNHP).
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 Listen Professional than 25%.
| dB SPL | Elex (Drop) power | Elex (Drop) voltage | Listen Professional power | Listen Professional voltage |
|---|---|---|---|---|
| 80 | 4.0 µW | 18 mV | 1.9 µW | 8 mV |
| 85 | 0.01 mW | 32 mV | 6.2 µW | 14 mV |
| 90 | 0.04 mW | 56 mV | 0.02 mW | 25 mV |
| 95 | 0.13 mW | 0.10 V | 0.06 mW | 44 mV |
| 100 | 0.40 mW | 0.18 V | 0.19 mW | 79 mV |
| 105 | 1.3 mW | 0.32 V | 0.62 mW | 0.14 V |
| Source | Price | Headroom, Elex (Drop) | Headroom, Listen Professional | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 14.8 dB | 21.9 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 23.1 dB | 30.1 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 20.0 dB | 27.1 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 67 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 67 is the JadeAudio JA11, at $20. It leaves 14.8 dB of headroom on the Elex (Drop) and 21.9 dB on the Listen Professional, its output impedance is 0.5 Ω against a one-eighth limit of 10.00 Ω and 4.00 Ω, and its noise figure puts the hiss floor 20 dB and 13 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 Listen 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.