Both are audio interfaces, $129 against $139. 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 Focusrite Scarlett Solo 4th gen reaches 100 dB on 552 of the 567 models here, the Audient EVO 4 on 543.
| Specification | Audient EVO 4 | Focusrite Scarlett Solo 4th gen |
|---|---|---|
| Power into 32Ω | 22 mW | 31 mW |
| Power into 150Ω | 14 mW | 19 mW |
| Power into 300Ω | 11 mW | 22 mW |
| Power into 600Ω | 10 mW | 11 mW |
| Output impedance | 50 Ω | 50 Ω |
| Output noise | not published | not published |
| Price | $129 | $139 |
| Headphones it reaches 100 dB on out of 567 | 543 | 552 |
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.
9 headphones reach 100 dB on the Focusrite Scarlett Solo 4th gen but not on the Audient EVO 4 — Dan Clark Audio AEON 2 Closed, Dan Clark Audio AEON 2 Noire, Dan Clark Audio AEON 2 Open, 6 more.
543 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 4 and Focusrite Scarlett Solo 4th gen. Or put either against your own headphones in the source comparison tool.