Short answer
Both are audio interfaces, $1495 against $1399.
The RME ADI-2 DAC FS reaches 100 dB on 567 of the 567 models here, the Apogee Symphony Desktop on 566.
| Specification | Apogee Symphony Desktop | RME ADI-2 DAC FS |
|---|---|---|
| Power into 32Ω | 490 mW | 1.2 W |
| Power into 150Ω | 145 mW | 256 mW |
| Power into 300Ω | 103 mW | 128 mW |
| Power into 600Ω | 90 mW | 64 mW |
| Output impedance | not published | 0.1 Ω |
| Output noise | not published | 2.18 µV |
| Price | $1495 | $1399 |
| Headphones it reaches 100 dB on out of 567 | 566 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Apogee Symphony Desktop | RME ADI-2 DAC FS |
|---|---|---|
| 32 Ω | Derived | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Published | Derived |
Both makers publish a power rating. Apogee Symphony Desktop publishes at 600 Ω; RME ADI-2 DAC FS at 32 Ω. The other rows are worked out from those.
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 ADI-2 DAC FS figure is the maker’s own. On those rows the derived number is the one to doubt first.
1 headphone reaches 100 dB on the RME ADI-2 DAC FS but not on the Apogee Symphony Desktop — Symphonium Titan.
566 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: RME ADI-2 DAC FS has +41 dB of headroom there against +36 dB. 5 dB is about 3.4 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Apogee Symphony Desktop because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | Apogee Symphony Desktop headroom | RME ADI-2 DAC FS headroom | Apogee Symphony Desktop hiss | RME ADI-2 DAC FS hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +36 dB | +41 dB | not published | 21 dB |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +16 dB | +21 dB | not published | 1 dB |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +25 dB | +28 dB | not published | -1 dB |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +22 dB | +24 dB | not published | -5 dB |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +17 dB | +21 dB | not published | -6 dB |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +18 dB | +17 dB | not published | -12 dB |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +12 dB | +13 dB | not published | -16 dB |
| HiFiMAN Susvara | 60 Ω | 50 mW | +8 dB | +11 dB | not published | -18 dB |
The Apogee Symphony Desktop costs $96 more than the RME ADI-2 DAC FS, and on these three axes the money buys nothing: among the 567 models here there is not one that the Apogee Symphony Desktop handles and the RME ADI-2 DAC FS does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper RME ADI-2 DAC FS drives one model to 100 dB that the Apogee Symphony Desktop does not.
Only published figures count here; blank axes are counted separately.
Each in full: Apogee Symphony Desktop and RME ADI-2 DAC FS.