Short answer
Both are audio interfaces, $599 against $570.
The Arturia AudioFuse Rev2 reaches 100 dB on 564 of the 567 models here, the Focusrite Scarlett 18i16 (4th Gen) on 553.
| Specification | Arturia AudioFuse Rev2 | Focusrite Scarlett 18i16 (4th Gen) |
|---|---|---|
| Power into 32Ω | 187 mW | 55 mW |
| Power into 150Ω | 40 mW | 27 mW |
| Power into 300Ω | 20 mW | 27 mW |
| Power into 600Ω | 10.0 mW | 14 mW |
| Output impedance | 33 Ω | 11 Ω |
| Output noise | not published | not published |
| Price | $599 | $570 |
| Headphones it reaches 100 dB on out of 567 | 564 | 553 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Arturia AudioFuse Rev2 | Focusrite Scarlett 18i16 (4th Gen) |
|---|---|---|
| 32 Ω | Upper bound | Derived |
| 150 Ω | Upper bound | Derived |
| 300 Ω | Upper bound | Published |
| 600 Ω | Upper bound | Derived |
These two columns are not the same kind of number, and that matters more than the gap between them. Focusrite Scarlett 18i16 (4th Gen) publishes a power rating (at 300 Ω); Arturia AudioFuse Rev2 publishes no power figure at any load, only a maximum output voltage, so every milliwatt in its column is a ceiling worked out from that voltage.
A ceiling assumes the amplifier holds that voltage into the load, and nothing on Arturia AudioFuse Rev2’s own sheet says it does. It is the most flattering reading available, and it is used here only because the alternative is a blank. Where the Arturia AudioFuse Rev2 column looks the stronger of the two, treat the difference as unproven rather than measured. 24 of the 280 sources here are in that position, with no published power rating at any load.
11 headphones reach 100 dB on the Arturia AudioFuse Rev2 but not on the Focusrite Scarlett 18i16 (4th Gen) — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 8 more.
25 headphones are left alone by the Focusrite Scarlett 18i16 (4th Gen) under the one-eighth rule but coloured by the Arturia AudioFuse Rev2 (AKG K612 Pro, Audeze LCD-3, Audeze LCD-4, 22 more).
553 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 HiFiMAN HE400se: Arturia AudioFuse Rev2 has +13 dB of headroom there against +7 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 Arturia AudioFuse Rev2 and Focusrite Scarlett 18i16 (4th Gen) because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Arturia AudioFuse Rev2 headroom | Focusrite Scarlett 18i16 (4th Gen) headroom | Arturia AudioFuse Rev2 hiss | Focusrite Scarlett 18i16 (4th Gen) hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +31 dB damping | +26 dB damping | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +11 dB damping | +6 dB damping | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +20 dB damping | +16 dB damping | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +16 dB damping | +16 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +13 dB damping | +7 dB damping | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +9 dB | +10 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +5 dB | +6 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +3 dB damping | -1 dB damping | not published | not published |
The Arturia AudioFuse Rev2 costs $29 more than the Focusrite Scarlett 18i16 (4th Gen). Out of the 567 models here, that difference buys 11 more models driven to 100 dB.
It does not run one way only: the cheaper Focusrite Scarlett 18i16 (4th Gen) leaves 25 models alone under the one-eighth rule that the Arturia AudioFuse Rev2 does not, which is the part worth checking against your own headphones before paying the difference.
Only published figures count here; blank axes are counted separately.
Each in full: Arturia AudioFuse Rev2 and Focusrite Scarlett 18i16 (4th Gen).