Both are audio interfaces, $410 against $400. 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 IK Multimedia AXE I/O reaches 100 dB on 561 of the 567 models here, the Focusrite Scarlett 16i16 (4th Gen) on 553.
| Specification | Focusrite Scarlett 16i16 (4th Gen) | IK Multimedia AXE I/O |
|---|---|---|
| Power into 32Ω | 55 mW | 115 mW |
| Power into 150Ω | 27 mW | 60 mW |
| Power into 300Ω | 27 mW | 30 mW |
| Power into 600Ω | 14 mW | 15 mW |
| Output impedance | 11 Ω | <0.1 Ω |
| Output noise | not published | not published |
| Price | $410 | $400 |
| Headphones it reaches 100 dB on out of 567 | 553 | 561 |
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.
| Load | Focusrite Scarlett 16i16 (4th Gen) | IK Multimedia AXE I/O |
|---|---|---|
| 32 Ω | Derived | Derived |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Derived | Derived |
Only one of these two columns starts from a power rating. Focusrite Scarlett 16i16 (4th Gen) publishes one at 300 Ω; IK Multimedia AXE I/O publishes none at any of these four loads, so its column is worked out from power it published at other loads. Both are arithmetic on a maker’s own figures rather than guesses, and the method used for the IK Multimedia AXE I/O understates rather than flatters — but at 300 Ω is the only load here at which its maker can be held to a figure.
What each of these labels means, and why a derived figure is still worth printing, is set out in how this data was built.
8 headphones reach 100 dB on the IK Multimedia AXE I/O but not on the Focusrite Scarlett 16i16 (4th Gen) — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 5 more.
520 headphones are left alone by the IK Multimedia AXE I/O under the one-eighth rule but coloured by the Focusrite Scarlett 16i16 (4th Gen) (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 517 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.
The counts above say how many models the two treat differently. This says by how much. The same 8 headphones appear on every page of this kind, ordered from the easiest to drive to the hardest, so a row can be read across pages as well as across columns. Headroom is at a 100 dB SPL peak.
The widest gap on the list is the HiFiMAN Susvara: IK Multimedia AXE I/O has +5 dB of headroom there against -1 dB. 6 dB is about 3.9 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Focusrite Scarlett 16i16 (4th Gen) and IK Multimedia AXE I/O because neither maker publishes no output noise figure. That is a gap in the specification, not a quiet amplifier, and it is left blank here rather than filled with a plausible number.
| Headphone | Impedance | Needs | Focusrite Scarlett 16i16 (4th Gen) headroom | IK Multimedia AXE I/O headroom | Focusrite Scarlett 16i16 (4th Gen) hiss | IK Multimedia AXE I/O hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +26 dB damping | +29 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +6 dB damping | +9 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +16 dB damping | +22 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +16 dB | +18 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +7 dB damping | +11 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +10 dB | +11 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +6 dB | +7 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | -1 dB damping | +5 dB | not published | not published |
The Focusrite Scarlett 16i16 (4th Gen) costs $10 more than the IK Multimedia AXE I/O, and on these three axes the money buys nothing: among the 567 models here there is not one that the Focusrite Scarlett 16i16 (4th Gen) handles and the IK Multimedia AXE I/O does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper IK Multimedia AXE I/O drives 8 models to 100 dB and leaves 520 alone under the one-eighth rule that the Focusrite Scarlett 16i16 (4th Gen) does not.
Everything in this paragraph counts only figures the two makers published. An advantage on an axis one of them leaves blank cannot be counted, and is not counted — how often that happens is its own page.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Focusrite Scarlett 16i16 (4th Gen) and IK Multimedia AXE I/O. Or put either against your own headphones in the source comparison tool.