Short answer
Both are audio interfaces, $349 against $432.
The Audient iD14 MkII reaches 100 dB on 561 of the 567 models here, the Roland Rubix44 on 542.
| Specification | Audient iD14 MkII | Roland Rubix44 |
|---|---|---|
| Power into 32Ω | 112 mW | 19 mW |
| Power into 150Ω | 75 mW | 15 mW |
| Power into 300Ω | 55 mW | 9.4 mW |
| Power into 600Ω | 50 mW | 5.4 mW |
| Output impedance | not published | 47 Ω |
| Output noise | not published | not published |
| Price | $349 | $432 |
| Headphones it reaches 100 dB on out of 567 | 561 | 542 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Audient iD14 MkII | Roland Rubix44 |
|---|---|---|
| 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.
19 headphones reach 100 dB on the Audient iD14 MkII but not on the Roland Rubix44 — Audeze LCD-5, Dan Clark Audio AEON 2 Closed, Dan Clark Audio AEON 2 Noire, 16 more.
542 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 Susvara: Audient iD14 MkII has +4 dB of headroom there against -4 dB. 9 dB is about 7.8 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Audient iD14 MkII and Roland Rubix44 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Audient iD14 MkII headroom | Roland Rubix44 headroom | Audient iD14 MkII hiss | Roland Rubix44 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +29 dB | +21 dB damping | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +9 dB | +1 dB damping | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +22 dB | +13 dB damping | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +20 dB | +12 dB damping | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +11 dB | +3 dB damping | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +15 dB | +6 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +9 dB | +2 dB damping | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +4 dB | -4 dB damping | not published | not published |
The Roland Rubix44 costs $83 more than the Audient iD14 MkII, and on these three axes the money buys nothing: among the 567 models here there is not one that the Roland Rubix44 handles and the Audient iD14 MkII does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper Audient iD14 MkII drives 19 models to 100 dB that the Roland Rubix44 does not.
Only published figures count here; blank axes are counted separately.
Each in full: Audient iD14 MkII and Roland Rubix44.