Short answer
Both are portable players, $499 against $350.
The FiiO M11S reaches 100 dB on 566 of the 567 models here, the Moondrop DISCDREAM2 ULTRA on 561.
| Specification | FiiO M11S | Moondrop DISCDREAM2 ULTRA |
|---|---|---|
| Power into 32Ω | 200 mW | 112 mW |
| Power into 150Ω | 44 mW | 24 mW |
| Power into 300Ω | 23 mW | 12 mW |
| Power into 600Ω | 12 mW | 6.0 mW |
| Output impedance | 1.5 Ω | not published |
| Output noise | 1.8 µV | not published |
| Price | $499 | $350 |
| Headphones it reaches 100 dB on out of 567 | 566 | 561 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | FiiO M11S | Moondrop DISCDREAM2 ULTRA |
|---|---|---|
| Socket | 4.4mm | 4.4mm |
| Power into 32Ω | 670 mW | 222 mW |
| Power into 300Ω | 90 mW | 24 mW derived |
| Output impedance | 2.6 Ω | not published |
| Output noise | 3.1 µV | not published |
| Headphones it reaches 100 dB on out of 567 | 566 | 565 |
Through the balanced sockets the FiiO M11S reaches 100 dB on 566 of the 567 models here and the Moondrop DISCDREAM2 ULTRA on 565. Derived figures are worked out from the loads the maker did publish.
| Load | FiiO M11S | Moondrop DISCDREAM2 ULTRA |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. FiiO M11S publishes at 32 Ω and at 300 Ω; Moondrop DISCDREAM2 ULTRA at 32 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 300 Ω only the FiiO M11S figure is the maker’s own. On those rows the derived number is the one to doubt first.
5 headphones reach 100 dB on the FiiO M11S but not on the Moondrop DISCDREAM2 ULTRA — Moondrop COSMO, Moondrop PARA, Symphonium Crimson, 2 more.
561 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Shure SE846: FiiO M11S has +36 dB of headroom there against +29 dB. 7 dB is about 5.4 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Moondrop DISCDREAM2 ULTRA because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | FiiO M11S headroom | Moondrop DISCDREAM2 ULTRA headroom | FiiO M11S hiss | Moondrop DISCDREAM2 ULTRA hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +36 dB damping | +29 dB | 20 dB | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +16 dB damping | +9 dB | -0 dB | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +21 dB | +18 dB | -2 dB | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +16 dB | +14 dB | -7 dB | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +15 dB | +10 dB | -8 dB | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +10 dB | +7 dB | -14 dB | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +5 dB | +3 dB | -18 dB | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +3 dB | +1 dB | -20 dB | not published |
The FiiO M11S costs $149 more than the Moondrop DISCDREAM2 ULTRA. Out of the 567 models here, that difference buys 5 more models driven to 100 dB.
Nothing runs the other way: there is no axis here on which the cheaper of the two does better.
Only published figures count here; blank axes are counted separately.
Each in full: FiiO M11S and Moondrop DISCDREAM2 ULTRA.