The IK Multimedia AXE I/O ONE is an audio interface at $130. It delivers 26 mW into 32Ω and 6.7 mW into 300Ω, which ranks it 270 of 280 for raw power among the sources in this database.
Measured at 100 dB SPL it has comfortable headroom on 397 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 135, only marginal on 18 and not enough power for 17. Power is published at 50Ω; the rest of the table is derived from those figures. Output noise is not published, so the hiss estimate cannot be run.
The manufacturer publishes 40 mW into 50Ω. Everything else in the table above is worked out from those figures, and this table says which is which.
Derivation holds output voltage steady between and beyond the published loads rather than output power, because that is what an amplifier actually does. The full method is written up here.
Source: ikmultimedia.com.
| Load | Power | Status | How it was arrived at |
|---|---|---|---|
| 32 Ω | 26 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
| 50 Ω | 40 mW | Published | the manufacturer publishes this figure at this exact load |
| 150 Ω | 13 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
| 300 Ω | 6.7 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
| 600 Ω | 3.3 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
Ordered from easiest to hardest to drive. Headroom is measured at 100 dB SPL, which is louder than almost anyone listens — a small negative number means the source still plays loud, just without reserve for peaks.
These figures come from each manufacturer's own sensitivity rating. A handful of planars — the HiFiMAN Susvara and the Abyss AB-1266 in particular — are widely reported to need far more than their published sensitivity implies, so treat a bare pass on those as optimistic rather than settled.
| Headphone | Impedance | Sensitivity | Needs | Headroom | Verdict |
|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 114.0 dB/mW | 0.04 mW | +23 dB | Comfortable |
| 64 Audio U12t | 12.6 Ω | 108.0 dB/mW | 0.16 mW | +18 dB | Comfortable |
| Shure SE215 | 17 Ω | 107.0 dB/mW | 0.20 mW | +18 dB | Comfortable |
| Moondrop Aria | 32 Ω | 107.1 dB/mW | 0.19 mW | +21 dB | Comfortable |
| Audeze LCD-X 2021 | 20 Ω | 103.0 dB/mW | 0.50 mW | +15 dB | Comfortable |
| Truthear Hexa | 20.5 Ω | 103.1 dB/mW | 0.49 mW | +15 dB | Comfortable |
| Sennheiser IE 200 | 18 Ω | 101.6 dB/mW | 0.69 mW | +13 dB | Comfortable |
| Sony MDR-7506 | 63 Ω | 106.0 dB/mW | 0.25 mW | +21 dB | Comfortable |
| Meze 99 Classics | 32 Ω | 103.0 dB/mW | 0.50 mW | +17 dB | Comfortable |
| Focal Clear MG | 55 Ω | 104.0 dB/mW | 0.40 mW | +20 dB | Comfortable |
| Philips SHP9500 | 32 Ω | 101.0 dB | 0.79 mW | +15 dB | Comfortable |
| Focal Utopia | 80 Ω | 104.0 dB/mW | 0.40 mW | +18 dB | Comfortable |
| Meze Empyrean | 32 Ω | 100.0 dB | 1.0 mW | +14 dB | Comfortable |
| Campfire Audio Andromeda 2020 | 9 Ω | 94.0 dB | 4.0 mW | +3 dB | Marginal |
| Etymotic ER2SE | 15 Ω | 96.0 dB/mW | 2.5 mW | +7 dB | Enough |
| AKG K371 | 32 Ω | 99.1 dB/mW | 1.2 mW | +13 dB | Comfortable |
| Audio-Technica ATH-M50X | 38 Ω | 99.0 dB/mW | 1.3 mW | +14 dB | Comfortable |
| Beyerdynamic DT 900 Pro X | 48 Ω | 100.0 dB/mW | 1.0 mW | +16 dB | Comfortable |
| Audeze LCD-2 Classic | 70 Ω | 101.0 dB/mW | 0.79 mW | +16 dB | Comfortable |
| Grado SR80x | 38 Ω | 98.0 dB/mW | 1.6 mW | +13 dB | Comfortable |
| Sennheiser HD 560S | 120 Ω | 100.8 dB/mW | 0.83 mW | +13 dB | Comfortable |
| HiFiMAN Edition XS | 18 Ω | 92.0 dB | 6.3 mW | +4 dB | Enough |
| HiFiMAN Arya Stealth | 32 Ω | 94.0 dB | 4.0 mW | +8 dB | Enough |
| Dan Clark Audio AEON 2 Closed | 13 Ω | 90.0 dB/mW | 10 mW | +0 dB | Marginal |
| Audeze LCD-5 | 14 Ω | 90.0 dB/mW | 10 mW | +0 dB | Marginal |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 102.0 dB/mW | 0.63 mW | +11 dB | Comfortable |
| HiFiMAN HE400se | 25 Ω | 91.0 dB | 7.9 mW | +4 dB | Enough |
| HiFiMAN Sundara | 32 Ω | 92.0 dB | 6.3 mW | +6 dB | Enough |
| Dan Clark Audio Stealth | 23 Ω | 90.0 dB/mW | 10 mW | +3 dB | Marginal |
| Fostex T50RP MK3 | 50 Ω | 92.0 dB/mW | 6.3 mW | +8 dB | Enough |
| AKG K702 | 62 Ω | 92.9 dB/mW | 5.1 mW | +8 dB | Enough |
| ZMF Verite Closed | 300 Ω | 99.0 dB/mW | 1.3 mW | +7 dB | Enough |
| Sennheiser HD 650 | 300 Ω | 97.8 dB/mW | 1.7 mW | +6 dB | Enough |
| Sennheiser HD 800S | 300 Ω | 96.8 dB/mW | 2.1 mW | +5 dB | Enough |
| Beyerdynamic DT 770 Pro (250Ω) | 250 Ω | 96.0 dB | 2.5 mW | +5 dB | Enough |
| Audio-Technica ATH-R70X | 470 Ω | 98.0 dB/mW | 1.6 mW | +4 dB | Enough |
| ZMF Atrium | 300 Ω | 96.0 dB/mW | 2.5 mW | +4 dB | Enough |
| Abyss AB-1266 Phi TC | 50 Ω | 88.0 dB/mW | 16 mW | +4 dB | Enough |
| Sennheiser HD 600 | 300 Ω | 91.8 dB/mW | 6.6 mW | +0 dB | Marginal |
| HiFiMAN Susvara | 60 Ω | 83.0 dB | 50 mW | -2 dB | Not enough |
The manufacturer does not publish an output noise figure for this source, so the hiss estimate that runs on every other page here cannot be run on this one. Rather than substitute a plausible number, this page leaves the question open.
If you know the noise figure from a measurement you trust, the hiss calculator takes it directly and tells you where that noise lands in your own in-ears.
At 0Ω output impedance this source satisfies the one-eighth rule with every headphone in the database, down to the 3Ω in-ears. Nothing here will have its frequency response shaped by the source.
The rule is a rule of thumb, not physics: a source impedance below one eighth of the headphone's keeps the interaction under about 1 dB. The checker works it out for any pair.
| Source | Type | Price | Into 300 Ω | Output impedance | Output noise |
|---|---|---|---|---|---|
| iBasso DC03 Pro | USB dongle | $69 | 10 mW | 0.12 Ω | 0.9 µV |
| FiiO KA5 | USB dongle | $99 | 14 mW | 0.3 Ω | 1.6 µV |
| Schiit Magni Heresy | desktop amplifier | $99 | 410 mW | 0.25 Ω | 1.5 µV unverified |
Of the 280 sources here, 5 do everything the IK Multimedia AXE I/O ONE does as a headphone output: reach 100 dB on every headphone it reaches and stay inside the one-eighth rule wherever it does. The cheapest of them is the iBasso DC03 Pro at $69, against this one’s $130 — $61 less, and a USB dongle rather than an audio interface.
The cheaper one also publishes a noise figure, which the IK Multimedia AXE I/O ONE does not — so on the paperwork it is ahead, not merely level.
This counts a headphone output and nothing else. Inputs, converters, microphone preamps, balanced outputs, the volume control, the case and the warranty are all outside it, and any of them can be the reason to buy the dearer box. What the count does say is that the three numbers a maker can be held to do not separate them.
$129 · 22 mW into 32Ω · 50 Ω out
Compare →$139 · 31 mW into 32Ω · 50 Ω out
Compare →$119 · 32 mW into 32Ω · output Ω not published
Compare →$149 · 27 mW into 32Ω · output Ω not published
Compare →$149 · 139 mW into 32Ω · 10 Ω out
Compare →$149 · 84 mW into 32Ω · output Ω not published
Compare →Worked out in advance against its closest rivals: vs Arturia MiniFuse 1 · vs Arturia MiniFuse 2 · vs Audient EVO 4 · vs Focusrite Scarlett 2i2 4th gen · vs Focusrite Scarlett Solo 4th gen · vs IK Multimedia AXE I/O · vs Steinberg IXO22 · vs Tascam US-2x2HR · vs Zoom AMS-22 · vs Zoom AMS-24 · vs Zoom AMS-44. Each of those pages lists the headphones that tell the two apart.
Or put any two side by side in the source comparison tool, or run your own headphones through the amplifier matcher. Or see every IK source in the database, and how much of what this site says about them came from IK’s own documents.