Apogee Symphony Desktop vs RME Fireface UCX II

Both are audio interfaces, $1495 against $1749. 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 Apogee Symphony Desktop reaches 100 dB on 566 of the 567 models here, the RME Fireface UCX II on 564.

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. Apogee Symphony Desktop publishes at 600 Ω; RME Fireface UCX 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 600 Ω only the Apogee Symphony Desktop figure is the maker’s own and at 32 Ω only the RME Fireface UCX II 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 Apogee Symphony Desktop but not on the RME Fireface UCX II — Moondrop PARA, Symphonium Crimson.

564 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 Audio-Technica ATH-R70X: Apogee Symphony Desktop has +18 dB of headroom there against +10 dB. 8 dB is about 6.4 times the power, which matters for peaks rather than for how loud the music sits.

The hiss columns are empty for Apogee Symphony Desktop and RME Fireface UCX II because neither 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.

The RME Fireface UCX II costs $254 more than the Apogee Symphony Desktop, and on these three axes the money buys nothing: among the 567 models here there is not one that the RME Fireface UCX II handles and the Apogee Symphony Desktop does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper Apogee Symphony Desktop drives 2 models to 100 dB that the RME Fireface UCX II does not.

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: Apogee Symphony Desktop and RME Fireface UCX II. Or put either against your own headphones in the source comparison tool.