The RME ADI-2 Pro EX is an audio interface at $2499. It delivers 1.9 W into 32Ω and 370 mW into 300Ω, which ranks it 50 of 280 for raw power among the sources in this database.
Measured at 100 dB SPL it has comfortable headroom on 566 of the 567 dynamic and planar headphones catalogued here and enough but not generous on 1. Power is published at 16Ω, 32Ω, 300Ω; 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 2.1 W into 16Ω, 1.9 W into 32Ω, 370 mW into 300Ω. The rest of the table is worked out from those.
The balanced output is rated separately: 4.2 W into 32Ω through the 2 x 6.3 mm TRS (RME 'Advanced Balanced' mode uses both unbalanced jacks as one balanced pair) jack.
Derived rows hold output voltage steady, as an amplifier does (method).
The noise figure above is converted, not read. RME does not print microvolts for this one. It prints a signal-to-noise ratio together with the voltage that ratio is referenced to, in the same block of the same table: “Signal to Noise ratio (SNR) @ +7 dBu: 118 dB RMS unweighted, 121 dBA | Output level at 0 dBFS, Lo-Power, load 8 Ohm or up: +7 dBu (1.73 V)”. From those two numbers the noise follows by one division — 1.73 V ÷ 10(118/20) — which is where the 2.18 µV comes from, at the Lo-Power setting, podaje OBA: unweighted i A-weighted. This is the same situation as a sensitivity printed per volt instead of per milliwatt: published, but in a convention nobody converts.
Source: rme-audio.de.
| Load | Power | Status | How it was arrived at |
|---|---|---|---|
| 16 Ω | 2.1 W | Published | the manufacturer publishes this figure at this exact load |
| 32 Ω | 1.9 W | Published | the manufacturer publishes this figure at this exact load |
| 150 Ω | 540 mW | Derived | worked out between two published loads, holding output voltage linear between them |
| 300 Ω | 370 mW | Published | the manufacturer publishes this figure at this exact load |
| 600 Ω | 185 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
Easiest to hardest to drive, with headroom at a 100 dB SPL peak.
| Headphone | Impedance | Sensitivity | Needs | Headroom | Verdict |
|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 114.0 dB/mW | 0.04 mW | +45 dB | Comfortable audible hiss |
| 64 Audio U12t | 12.6 Ω | 108.0 dB/mW | 0.16 mW | +40 dB | Comfortable audible hiss |
| Shure SE215 | 17 Ω | 107.0 dB/mW | 0.20 mW | +40 dB | Comfortable audible hiss |
| Moondrop Aria | 32 Ω | 107.1 dB/mW | 0.19 mW | +40 dB | Comfortable faint hiss |
| Audeze LCD-X 2021 | 20 Ω | 103.0 dB/mW | 0.50 mW | +36 dB | Comfortable faint hiss |
| Truthear Hexa | 20.5 Ω | 103.1 dB/mW | 0.49 mW | +36 dB | Comfortable faint hiss |
| Sennheiser IE 200 | 18 Ω | 101.6 dB/mW | 0.69 mW | +35 dB | Comfortable faint hiss |
| Sony MDR-7506 | 63 Ω | 106.0 dB/mW | 0.25 mW | +36 dB | Comfortable faint hiss |
| Meze 99 Classics | 32 Ω | 103.0 dB/mW | 0.50 mW | +36 dB | Comfortable faint hiss |
| Focal Clear MG | 55 Ω | 104.0 dB/mW | 0.40 mW | +35 dB | Comfortable faint hiss |
| Philips SHP9500 | 32 Ω | 101.0 dB | 0.79 mW | +34 dB | Comfortable faint hiss |
| Focal Utopia | 80 Ω | 104.0 dB/mW | 0.40 mW | +33 dB | Comfortable faint hiss |
| Meze Empyrean | 32 Ω | 100.0 dB | 1.0 mW | +33 dB | Comfortable faint hiss |
| Campfire Audio Andromeda 2020 | 9 Ω | 94.0 dB | 4.0 mW | +25 dB | Comfortable faint hiss |
| Etymotic ER2SE | 15 Ω | 96.0 dB/mW | 2.5 mW | +29 dB | Comfortable faint hiss |
| AKG K371 | 32 Ω | 99.1 dB/mW | 1.2 mW | +32 dB | Comfortable faint hiss |
| Audio-Technica ATH-M50X | 38 Ω | 99.0 dB/mW | 1.3 mW | +31 dB | Comfortable |
| Beyerdynamic DT 900 Pro X | 48 Ω | 100.0 dB/mW | 1.0 mW | +31 dB | Comfortable |
| Audeze LCD-2 Classic | 70 Ω | 101.0 dB/mW | 0.79 mW | +31 dB | Comfortable |
| Grado SR80x | 38 Ω | 98.0 dB/mW | 1.6 mW | +30 dB | Comfortable |
| Sennheiser HD 560S | 120 Ω | 100.8 dB/mW | 0.83 mW | +29 dB | Comfortable |
| HiFiMAN Edition XS | 18 Ω | 92.0 dB | 6.3 mW | +25 dB | Comfortable |
| HiFiMAN Arya Stealth | 32 Ω | 94.0 dB | 4.0 mW | +27 dB | Comfortable |
| Dan Clark Audio AEON 2 Closed | 13 Ω | 90.0 dB/mW | 10 mW | +22 dB | Comfortable |
| Audeze LCD-5 | 14 Ω | 90.0 dB/mW | 10 mW | +23 dB | Comfortable |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 102.0 dB/mW | 0.63 mW | +28 dB | Comfortable |
| HiFiMAN HE400se | 25 Ω | 91.0 dB | 7.9 mW | +24 dB | Comfortable |
| HiFiMAN Sundara | 32 Ω | 92.0 dB | 6.3 mW | +25 dB | Comfortable |
| Dan Clark Audio Stealth | 23 Ω | 90.0 dB/mW | 10 mW | +23 dB | Comfortable |
| Fostex T50RP MK3 | 50 Ω | 92.0 dB/mW | 6.3 mW | +23 dB | Comfortable |
| AKG K702 | 62 Ω | 92.9 dB/mW | 5.1 mW | +23 dB | Comfortable |
| ZMF Verite Closed | 300 Ω | 99.0 dB/mW | 1.3 mW | +25 dB | Comfortable |
| Sennheiser HD 650 | 300 Ω | 97.8 dB/mW | 1.7 mW | +23 dB | Comfortable |
| Sennheiser HD 800S | 300 Ω | 96.8 dB/mW | 2.1 mW | +22 dB | Comfortable |
| Beyerdynamic DT 770 Pro (250Ω) | 250 Ω | 96.0 dB | 2.5 mW | +22 dB | Comfortable |
| Audio-Technica ATH-R70X | 470 Ω | 98.0 dB/mW | 1.6 mW | +22 dB | Comfortable |
| ZMF Atrium | 300 Ω | 96.0 dB/mW | 2.5 mW | +22 dB | Comfortable |
| Abyss AB-1266 Phi TC | 50 Ω | 88.0 dB/mW | 16 mW | +19 dB | Comfortable |
| Sennheiser HD 600 | 300 Ω | 91.8 dB/mW | 6.6 mW | +17 dB | Comfortable |
| HiFiMAN Susvara | 60 Ω | 83.0 dB | 50 mW | +13 dB | Comfortable |
At 2.18 µV of output noise, here is where that noise lands in the five most revealing in-ears in the database.
This one hisses. With the most sensitive in-ears in the database its own noise lands around 28 dB SPL, which you will hear between tracks and in quiet passages.
| In-ear | Impedance | Sensitivity | Hiss level |
|---|---|---|---|
| Simgot EA500 | 16 Ω | 141.0 dB/V | 28 dB SPL |
| Tanchjim EA FORCE | 17 Ω | 137.7 dB/V | 24 dB SPL |
| Shure SE846 | 9 Ω | 134.5 dB/V | 21 dB SPL |
| Campfire Audio Clara | 13.3 Ω | 134.1 dB/V | 21 dB SPL |
| 64 Audio Fourte | 10 Ω | 134.0 dB/V | 21 dB SPL |
At 0.1Ω 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.
| Source | Type | Price | Into 300 Ω | Output impedance | Output noise |
|---|---|---|---|---|---|
| Schiit Magni Unity | desktop amplifier | $119 | 415 mW | 0.1 Ω | 1.59 µV |
| Topping L30 II | desktop amplifier | $149 | 560 mW | 0.1 Ω | 0.3 µV |
| SMSL HO100 | desktop amplifier | $160 | 200 mW | <0.1 Ω | 1.3 µV |
Of the 280 sources here, 11 do everything the RME ADI-2 Pro EX does as a headphone output: reach 100 dB on every headphone it reaches, stay inside the one-eighth rule wherever it does and stay under the audible-hiss threshold wherever it does. The cheapest of them is the Schiit Magni Unity at $119, against this one’s $2499 — $2380 less, and a desktop amplifier rather than an audio interface.
This counts the headphone output only; inputs, converters, the volume control and the build are outside it.
$2790 · 961 mW into 32Ω · 0.035 Ω out
Compare →$2199 · 3.0 W into 32Ω · 0.1 Ω out
Compare →$2799 · 200 mW into 32Ω · 2 Ω out
Compare →$3199 · 200 mW into 32Ω · 2 Ω out
Compare →$1749 · 210 mW into 32Ω · 1 Ω out
Compare →$3499 · 1.3 W into 32Ω · output Ω not published
Compare →Compared with its closest rivals: vs Audient Horizon 8P · vs Audient ORIA · vs Merging Anubis · vs RME Babyface Pro FS · vs RME Fireface UCX II · vs RME Fireface UFX II · vs RME Fireface UFX III.