Both are audio interfaces, $649 against $1495. 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 Duet 3 reaches 100 dB on 567 of the 567 models here, the Apogee Symphony Desktop on 566.
| Specification | Apogee Duet 3 | Apogee Symphony Desktop |
|---|---|---|
| Power into 32Ω | 1.2 W | 490 mW |
| Power into 150Ω | 252 mW | 145 mW |
| Power into 300Ω | 126 mW | 103 mW |
| Power into 600Ω | 63 mW | 90 mW |
| Output impedance | 0.5 Ω | not published |
| Output noise | not published | not published |
| Price | $649 | $1495 |
| Headphones it reaches 100 dB on out of 567 | 567 | 566 |
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.
1 headphone reaches 100 dB on the Apogee Duet 3 but not on the Apogee Symphony Desktop — Symphonium Titan.
566 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.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Apogee Duet 3 and Apogee Symphony Desktop. Or put either against your own headphones in the source comparison tool.