Both are portable players, $1799 against $1399. 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 M27 reaches 100 dB on 567 of the 567 models here, the Sony NW-WM1AM2 on 552.
| Specification | FiiO M27 | Sony NW-WM1AM2 |
|---|---|---|
| Power into 32Ω | 1.8 W | 30 mW |
| Power into 150Ω | 391 mW | 6.4 mW |
| Power into 300Ω | 200 mW | 3.2 mW |
| Power into 600Ω | 100 mW | 1.6 mW |
| Output impedance | 0.5 Ω | 1 Ω unverified |
| Output noise | 3.9 µV | 3 µV unverified |
| Price | $1799 | $1399 |
| Headphones it reaches 100 dB on out of 567 | 567 | 552 |
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.
| Load | FiiO M27 | Sony NW-WM1AM2 |
|---|---|---|
| 32 Ω | Published | Derived |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Derived | Derived |
Only one of these two columns starts from a power rating. FiiO M27 publishes one at 32 Ω and at 300 Ω; Sony NW-WM1AM2 publishes none at any of these four loads, so its column is worked out from power it published at other loads. Both are arithmetic on a maker’s own figures rather than guesses, and the method used for the Sony NW-WM1AM2 understates rather than flatters — but at 32 Ω and at 300 Ω are the only loads here at which its maker can be held to a figure.
What each of these labels means, and why a derived figure is still worth printing, is set out in how this data was built.
15 headphones reach 100 dB on the FiiO M27 but not on the Sony NW-WM1AM2 — Beyerdynamic DT 880 Edition (600Ω), Beyerdynamic DT 990 Edition (600Ω), HiFiMAN HE-6se V2, 12 more.
552 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.
The counts above say how many models the two treat differently. This says by how much. The same 8 headphones appear on every page of this kind, ordered from the easiest to drive to the hardest, so a row can be read across pages as well as across columns. Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Sennheiser HD 600: FiiO M27 has +15 dB of headroom there against -3 dB. 18 dB is about 63 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Sony NW-WM1AM2 because that maker publishes no output noise figure. That is a gap in the specification, not a quiet amplifier, and it is left blank here rather than filled with a plausible number.
| Headphone | Impedance | Needs | FiiO M27 headroom | Sony NW-WM1AM2 headroom | FiiO M27 hiss | Sony NW-WM1AM2 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +46 dB | +29 dB | 26 dB | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +26 dB | +9 dB | 6 dB | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +30 dB | +12 dB | 4 dB | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +26 dB | +8 dB | -0 dB | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +24 dB | +7 dB | -1 dB | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +19 dB | +1 dB | -7 dB | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +15 dB | -3 dB | -11 dB | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +13 dB | -5 dB | -13 dB | not published |
The FiiO M27 costs $400 more than the Sony NW-WM1AM2. Out of the 567 models here, that difference buys 15 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.
Everything in this paragraph counts only figures the two makers published. An advantage on an axis one of them leaves blank cannot be counted, and is not counted — how often that happens is its own page.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: FiiO M27 and Sony NW-WM1AM2. Or put either against your own headphones in the source comparison tool.