The FiiO FD11 is 24Ω at 111.0 dB/mW; the FiiO FP3 is 36Ω at 105.0 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 FP3 needs 6.0 dB more than the FD11 to reach the same loudness — 0.32 mW against 0.08 mW.
| Specification | FD11 | FP3 |
|---|---|---|
| Impedance | 24 Ω | 36 Ω |
| Sensitivity | 111.0 dB/mW | 105.0 dB/mW |
| Sensitivity (voltage) | 127.2 dB/V | 119.4 dB/V |
| Power for 100 dB | 0.08 mW | 0.32 mW |
| Voltage for 100 dB | 44 mV | 0.11 V |
| Current for 100 dB | 1.8 mA | 3.0 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 3.00 Ω | 4.50 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.
15 sources stay below the audible-hiss threshold with the FP3 but cross it with the FD11 (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 12 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: FiiO FD11 and FiiO FP3. Every figure on this page comes from what FiiO published, or is derived from it — what that maker publishes, counted.