FiiO M27 vs HiBy R8 II

Both are portable players, $1799 against $1999. 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 HiBy R8 II on 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.

Both makers publish a power rating, which is less common than the table above makes it look: of the 280 sources here, 209 publish a figure at at least one load and only 2 publish one at all four. FiiO M27 publishes at 32 Ω and at 300 Ω; HiBy R8 II at 32 Ω. Every other row is worked out from those — between two published loads, or beyond them holding voltage constant, which understates rather than flatters.

So the two columns are not equally firm row by row: at 300 Ω only the FiiO M27 figure is the maker’s own. On those rows the derived number is the one to doubt first.

What each of these labels means, and why a derived figure is still worth printing, is set out in how this data was built.

2 headphones reach 100 dB on the FiiO M27 but not on the HiBy R8 II — Moondrop PARA, Symphonium Titan.

14 headphones are left alone by the FiiO M27 under the one-eighth rule but coloured by the HiBy R8 II (64 Audio Nio, 64 Audio Volur, Campfire Audio Andromeda 2023, 11 more).

14 headphones stay below the audible-hiss threshold on the HiBy R8 II but cross it on the FiiO M27 (Audio-Technica ATH-CKS1100, Austrian Audio Hi-X25BT, Beyerdynamic DJ 300 PRO X, 11 more).

565 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 Shure SE846: FiiO M27 has +46 dB of headroom there against +32 dB. 14 dB is about 24 times the power, which matters for peaks rather than for how loud the music sits.

Hiss is this source’s own noise, in decibels SPL, in that headphone — not a rating. Below about 20 dB SPL it is under the threshold of hearing in a quiet room; a negative figure means it is far below it.

The HiBy R8 II costs $200 more than the FiiO M27. Out of the 567 models here, that difference buys 14 more models kept below the audible-hiss threshold.

It does not run one way only: the cheaper FiiO M27 drives 2 models to 100 dB and leaves 14 alone under the one-eighth rule that the HiBy R8 II does not, which is the part worth checking against your own headphones before paying the difference.

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 HiBy R8 II. Or put either against your own headphones in the source comparison tool.