Both are audio interfaces, $400 against $130. 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 IK Multimedia AXE I/O ONE on 550.
| Specification | IK Multimedia AXE I/O | IK Multimedia AXE I/O ONE |
|---|---|---|
| Power into 32Ω | 115 mW | 26 mW |
| Power into 150Ω | 60 mW | 13 mW |
| Power into 300Ω | 30 mW | 6.7 mW |
| Power into 600Ω | 15 mW | 3.3 mW |
| Output impedance | <0.1 Ω | <0.1 Ω |
| Output noise | not published | not published |
| Price | $400 | $130 |
| Headphones it reaches 100 dB on out of 567 | 561 | 550 |
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.
11 headphones reach 100 dB on the IK Multimedia AXE I/O but not on the IK Multimedia AXE I/O ONE — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 8 more.
550 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: IK Multimedia AXE I/O and IK Multimedia AXE I/O ONE. Or put either against your own headphones in the source comparison tool.