Both are Bluetooth receivers, $36 against $109. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?
The FiiO BTR15 reaches 100 dB on 565 of the 567 models here, the FiiO BTR11 on 549.
| Specification | FiiO BTR11 | FiiO BTR15 |
|---|---|---|
| Power into 32Ω | 30 mW | 125 mW |
| Power into 150Ω | 6.2 mW | 28 mW |
| Power into 300Ω | 3.0 mW | 15 mW |
| Power into 600Ω | 1.5 mW | 7.5 mW |
| Output impedance | 0.5 Ω | 1.0 Ω |
| Output noise | 8.0 µV | 2.0 µV |
| Price | $36 | $109 |
| Headphones it reaches 100 dB on out of 567 | 549 | 565 |
A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.
16 headphones reach 100 dB on the FiiO BTR15 but not on the FiiO BTR11 — Audio-Technica ATH-R70xa, Beyerdynamic DT 880 Edition (600Ω), Beyerdynamic DT 990 Edition (600Ω), 13 more.
14 headphones are left alone by the FiiO BTR11 under the one-eighth rule but coloured by the FiiO BTR15 (64 Audio Nio, 64 Audio Volur, Campfire Audio Andromeda 2023, 11 more).
143 headphones stay below the audible-hiss threshold on the FiiO BTR15 but cross it on the FiiO BTR11 (64 Audio Aspire 1, 64 Audio Nio, 64 Audio Ocean, 140 more).
549 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: FiiO BTR11 and FiiO BTR15. Or put either against your own headphones in the source comparison tool.