The MOTU M4 is an audio interface at $279. It delivers 333 mW into 32Ω and 36 mW into 300Ω, which ranks it 126 of 280 for raw power among the sources in this database.
Measured at 100 dB SPL it has comfortable headroom on 549 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 14, only marginal on 2 and not enough power for 2. The maker publishes a maximum output voltage but no power figure at any load, so every number here is an upper bound rather than a rating. Output impedance is not published. Output noise is not published, so the hiss estimate cannot be run.
The manufacturer publishes a maximum output of 3.266 V but no power rating at any load. Every figure above is therefore a ceiling: the real output into a low impedance will be lower, possibly much lower.
Derived rows hold output voltage steady, as an amplifier does (method).
Source: cdn-data.motu.com.
| Load | Power | Status | How it was arrived at |
|---|---|---|---|
| 32 Ω | 333 mW | Upper bound | the manufacturer publishes a maximum output voltage but no power rating, so this is a ceiling, not a rating |
| 150 Ω | 71 mW | Upper bound | the manufacturer publishes a maximum output voltage but no power rating, so this is a ceiling, not a rating |
| 300 Ω | 36 mW | Upper bound | the manufacturer publishes a maximum output voltage but no power rating, so this is a ceiling, not a rating |
| 600 Ω | 18 mW | Upper bound | the manufacturer publishes a maximum output voltage but no power rating, so this is a ceiling, not a rating |
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 | +34 dB | Comfortable |
| 64 Audio U12t | 12.6 Ω | 108.0 dB/mW | 0.16 mW | +29 dB | Comfortable |
| Shure SE215 | 17 Ω | 107.0 dB/mW | 0.20 mW | +29 dB | Comfortable |
| Moondrop Aria | 32 Ω | 107.1 dB/mW | 0.19 mW | +32 dB | Comfortable |
| Audeze LCD-X 2021 | 20 Ω | 103.0 dB/mW | 0.50 mW | +26 dB | Comfortable |
| Truthear Hexa | 20.5 Ω | 103.1 dB/mW | 0.49 mW | +26 dB | Comfortable |
| Sennheiser IE 200 | 18 Ω | 101.6 dB/mW | 0.69 mW | +24 dB | Comfortable |
| Sony MDR-7506 | 63 Ω | 106.0 dB/mW | 0.25 mW | +28 dB | Comfortable |
| Meze 99 Classics | 32 Ω | 103.0 dB/mW | 0.50 mW | +28 dB | Comfortable |
| Focal Clear MG | 55 Ω | 104.0 dB/mW | 0.40 mW | +27 dB | Comfortable |
| Philips SHP9500 | 32 Ω | 101.0 dB | 0.79 mW | +26 dB | Comfortable |
| Focal Utopia | 80 Ω | 104.0 dB/mW | 0.40 mW | +25 dB | Comfortable |
| Meze Empyrean | 32 Ω | 100.0 dB | 1.0 mW | +25 dB | Comfortable |
| Campfire Audio Andromeda 2020 | 9 Ω | 94.0 dB | 4.0 mW | +14 dB | Comfortable |
| Etymotic ER2SE | 15 Ω | 96.0 dB/mW | 2.5 mW | +18 dB | Comfortable |
| AKG K371 | 32 Ω | 99.1 dB/mW | 1.2 mW | +24 dB | Comfortable |
| Audio-Technica ATH-M50X | 38 Ω | 99.0 dB/mW | 1.3 mW | +23 dB | Comfortable |
| Beyerdynamic DT 900 Pro X | 48 Ω | 100.0 dB/mW | 1.0 mW | +23 dB | Comfortable |
| Audeze LCD-2 Classic | 70 Ω | 101.0 dB/mW | 0.79 mW | +23 dB | Comfortable |
| Grado SR80x | 38 Ω | 98.0 dB/mW | 1.6 mW | +22 dB | Comfortable |
| Sennheiser HD 560S | 120 Ω | 100.8 dB/mW | 0.83 mW | +20 dB | Comfortable |
| HiFiMAN Edition XS | 18 Ω | 92.0 dB | 6.3 mW | +15 dB | Comfortable |
| HiFiMAN Arya Stealth | 32 Ω | 94.0 dB | 4.0 mW | +19 dB | Comfortable |
| Dan Clark Audio AEON 2 Closed | 13 Ω | 90.0 dB/mW | 10 mW | +11 dB | Comfortable |
| Audeze LCD-5 | 14 Ω | 90.0 dB/mW | 10 mW | +12 dB | Comfortable |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 102.0 dB/mW | 0.63 mW | +18 dB | Comfortable |
| HiFiMAN HE400se | 25 Ω | 91.0 dB | 7.9 mW | +15 dB | Comfortable |
| HiFiMAN Sundara | 32 Ω | 92.0 dB | 6.3 mW | +17 dB | Comfortable |
| Dan Clark Audio Stealth | 23 Ω | 90.0 dB/mW | 10 mW | +14 dB | Comfortable |
| Fostex T50RP MK3 | 50 Ω | 92.0 dB/mW | 6.3 mW | +15 dB | Comfortable |
| AKG K702 | 62 Ω | 92.9 dB/mW | 5.1 mW | +15 dB | Comfortable |
| ZMF Verite Closed | 300 Ω | 99.0 dB/mW | 1.3 mW | +15 dB | Comfortable |
| Sennheiser HD 650 | 300 Ω | 97.8 dB/mW | 1.7 mW | +13 dB | Comfortable |
| Sennheiser HD 800S | 300 Ω | 96.8 dB/mW | 2.1 mW | +12 dB | Comfortable |
| Beyerdynamic DT 770 Pro (250Ω) | 250 Ω | 96.0 dB | 2.5 mW | +12 dB | Comfortable |
| Audio-Technica ATH-R70X | 470 Ω | 98.0 dB/mW | 1.6 mW | +12 dB | Comfortable |
| ZMF Atrium | 300 Ω | 96.0 dB/mW | 2.5 mW | +12 dB | Comfortable |
| Abyss AB-1266 Phi TC | 50 Ω | 88.0 dB/mW | 16 mW | +11 dB | Comfortable |
| Sennheiser HD 600 | 300 Ω | 91.8 dB/mW | 6.6 mW | +7 dB | Enough |
| HiFiMAN Susvara | 60 Ω | 83.0 dB | 50 mW | +5 dB | Enough |
The manufacturer does not publish an output noise figure for this source, so there is no hiss estimate here. If you have a measured figure, the hiss calculator takes it.
The manufacturer does not publish an output impedance for this source. Without it, nothing here can say how this source will behave with a multi-driver in-ear.
With a measured figure, the checker works out the consequence.
| Source | Type | Price | Into 300 Ω | Output impedance | Output noise |
|---|---|---|---|---|---|
| FiiO KA11 | USB dongle | $29 | 22 mW | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | Bluetooth receiver | $59 | 10.0 mW | 0.6 Ω | 1.0 µV |
| Tempotec Sonata BHD Pro | USB dongle | $60 | 30 mW | 0.6 Ω unverified | 4 µV unverified |
Of the 280 sources here, 43 do everything the MOTU M4 does as a headphone output: reach 100 dB on every headphone it reaches. The cheapest of them is the FiiO KA11 at $29, against this one’s $279 — $250 less, and a USB dongle rather than an audio interface.
The cheaper one also publishes an output impedance and a noise figure, which the MOTU M4 does not — so on the paperwork it is ahead, not merely level.
This counts the headphone output only; inputs, converters, the volume control and the build are outside it.
$279 · 55 mW into 32Ω · 11 Ω out
Compare →$299 · 84 mW into 32Ω · output Ω not published
Compare →$299 · 240 mW into 32Ω · 0.5 Ω out
Compare →$299 · 86 mW into 32Ω · output Ω not published
Compare →$299 · 374 mW into 32Ω · 1 Ω out
Compare →$299 · 139 mW into 32Ω · 10 Ω out
Compare →Compared with its closest rivals: vs Arturia MiniFuse 4 · vs Focusrite Scarlett 4i4 4th gen · vs MOTU UltraLite-mk5 · vs Steinberg UR22C · vs Tascam US-2x2HR.