Audient EVO 4 vs Steinberg IXO22

Short answer

More power: the Steinberg IXO22, with 32 mW into 32 Ω; the Audient EVO 4 has 22 mW. The Audient EVO 4 drives 1 headphone to 100 dB that the Steinberg IXO22 cannot (Sennheiser HD 600). The Steinberg IXO22 drives 10 headphones to 100 dB that the Audient EVO 4 cannot (Dan Clark Audio AEON 2 Closed, Dan Clark Audio AEON 2 Noire, Dan Clark Audio AEON 2 Open, 7 more).
Hiss with sensitive IEMs: cannot be compared — neither maker publishes a noise figure.
Price: the Audient EVO 4 costs $10 more; what that buys on these numbers is set out further down, under What the price difference buys.

Both are audio interfaces, $129 against $119.

The Steinberg IXO22 reaches 100 dB on 552 of the 567 models here, the Audient EVO 4 on 543.

Every published figure, next to each other

Specification	Audient EVO 4	Steinberg IXO22
Power into 32Ω	22 mW	32 mW
Power into 150Ω	14 mW	11 mW
Power into 300Ω	11 mW	5.3 mW
Power into 600Ω	10 mW	2.7 mW
Output impedance	50 Ω	not published
Output noise	not published	not published
Price	$129	$119
Headphones it reaches 100 dB on out of 567	543	552

Not published means the maker leaves it out, so that axis cannot be compared.

Where each power figure comes from

Load	Audient EVO 4	Steinberg IXO22
32 Ω	Derived	Derived
150 Ω	Derived	Derived
300 Ω	Derived	Derived
600 Ω	Recomputed	Derived

Neither column is a maker’s power rating at these loads. Of the 280 sources here, 209 publish a figure at at least one load; these two do not, so every row above is derived — between or beyond the loads each maker did publish, holding output voltage as the maker’s own figures imply. The method understates rather than flatters, but it is still arithmetic rather than a rating.

What the labels mean.

The headphones that tell them apart

1 headphone reaches 100 dB on the Audient EVO 4 but not on the Steinberg IXO22 — Sennheiser HD 600.

10 headphones reach 100 dB on the Steinberg IXO22 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, 7 more.

542 of the 567 models here reach 100 dB on both.

Headroom and hiss on 8 models, both sources

Headroom is at a 100 dB SPL peak.

The widest gap on the list is the Audio-Technica ATH-R70X: Audient EVO 4 has +8 dB of headroom there against +3 dB. 5 dB is about 3 times the power, which matters for peaks rather than for how loud the music sits.

The hiss columns are empty for Audient EVO 4 and Steinberg IXO22 because neither maker publishes no output noise figure.

Headphone	Impedance	Needs	Audient EVO 4 headroom	Steinberg IXO22 headroom	Audient EVO 4 hiss	Steinberg IXO22 hiss
Shure SE846	9 Ω	0.04 mW	+22 dB damping	+24 dB	not published	not published
Campfire Audio Andromeda 2020	9 Ω	4.0 mW	+2 dB damping	+4 dB	not published	not published
Audeze LCD-2 Classic	70 Ω	0.79 mW	+15 dB damping	+15 dB	not published	not published
Beyerdynamic DT 1990 Pro (250Ω)	250 Ω	0.63 mW	+13 dB damping	+10 dB	not published	not published
HiFiMAN HE400se	25 Ω	7.9 mW	+4 dB damping	+5 dB	not published	not published
Audio-Technica ATH-R70X	470 Ω	1.6 mW	+8 dB	+3 dB	not published	not published
Sennheiser HD 600	300 Ω	6.6 mW	+2 dB damping	-1 dB	not published	not published
HiFiMAN Susvara	60 Ω	50 mW	-3 dB damping	-3 dB	not published	not published

The gap in dollars, against the gap in numbers

The Audient EVO 4 costs $10 more than the Steinberg IXO22. Out of the 567 models here, that difference buys 1 more model driven to 100 dB.

It does not run one way only: the cheaper Steinberg IXO22 drives 10 models to 100 dB that the Audient EVO 4 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.