Both are audio interfaces, $750 against $699. 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 Audient EVO 16 reaches 100 dB on 558 of the 567 models here, the Focusrite Scarlett 18i20 4th gen on 553.
| Specification | Audient EVO 16 | Focusrite Scarlett 18i20 4th gen |
|---|---|---|
| Power into 32Ω | 87 mW | 55 mW |
| Power into 150Ω | 49 mW | 27 mW |
| Power into 300Ω | 32 mW | 27 mW |
| Power into 600Ω | 24 mW | 14 mW |
| Output impedance | 50 Ω | 11 Ω |
| Output noise | not published | not published |
| Price | $750 | $699 |
| Headphones it reaches 100 dB on out of 567 | 558 | 553 |
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.
5 headphones reach 100 dB on the Audient EVO 16 but not on the Focusrite Scarlett 18i20 4th gen — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 2 more.
41 headphones are left alone by the Focusrite Scarlett 18i20 4th gen under the one-eighth rule but coloured by the Audient EVO 16 (AKG K612 Pro, Audeze LCD-3, Audeze LCD-4, 38 more).
553 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: Audient EVO 16 and Focusrite Scarlett 18i20 4th gen. Or put either against your own headphones in the source comparison tool.