The Tascam US-4x4HR is an audio interface at $249. It delivers 45 mW into 32Ω and 24 mW into 300Ω, which ranks it 253 of 280 for raw power among the sources in this database.
Measured at 100 dB SPL it has comfortable headroom on 451 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 91, only marginal on 11 and not enough power for 14. Power is published at 32Ω; 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 45 mW into 32Ω. The rest of the table is worked out from those.
Derived rows hold output voltage steady, as an amplifier does (method).
Source: tascam.com.
| Load | Power | Status | How it was arrived at |
|---|---|---|---|
| 32 Ω | 45 mW | Published | the manufacturer publishes this figure at this exact load |
| 150 Ω | 36 mW | Derived | worked out from the published figure and the published output impedance, through the divider that impedance creates |
| 300 Ω | 24 mW | Derived | worked out from the published figure and the published output impedance, through the divider that impedance creates |
| 600 Ω | 14 mW | Derived | worked out from the published figure and the published output impedance, through the divider that impedance creates |
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 | +25 dB | Comfortable damping |
| 64 Audio U12t | 12.6 Ω | 108.0 dB/mW | 0.16 mW | +20 dB | Comfortable damping |
| Shure SE215 | 17 Ω | 107.0 dB/mW | 0.20 mW | +21 dB | Comfortable damping |
| Moondrop Aria | 32 Ω | 107.1 dB/mW | 0.19 mW | +24 dB | Comfortable damping |
| Audeze LCD-X 2021 | 20 Ω | 103.0 dB/mW | 0.50 mW | +17 dB | Comfortable damping |
| Truthear Hexa | 20.5 Ω | 103.1 dB/mW | 0.49 mW | +18 dB | Comfortable damping |
| Sennheiser IE 200 | 18 Ω | 101.6 dB/mW | 0.69 mW | +16 dB | Comfortable damping |
| Sony MDR-7506 | 63 Ω | 106.0 dB/mW | 0.25 mW | +22 dB | Comfortable damping |
| Meze 99 Classics | 32 Ω | 103.0 dB/mW | 0.50 mW | +20 dB | Comfortable damping |
| Focal Clear MG | 55 Ω | 104.0 dB/mW | 0.40 mW | +20 dB | Comfortable damping |
| Philips SHP9500 | 32 Ω | 101.0 dB | 0.79 mW | +18 dB | Comfortable damping |
| Focal Utopia | 80 Ω | 104.0 dB/mW | 0.40 mW | +19 dB | Comfortable damping |
| Meze Empyrean | 32 Ω | 100.0 dB | 1.0 mW | +17 dB | Comfortable damping |
| Campfire Audio Andromeda 2020 | 9 Ω | 94.0 dB | 4.0 mW | +5 dB | Enough damping |
| Etymotic ER2SE | 15 Ω | 96.0 dB/mW | 2.5 mW | +9 dB | Enough damping |
| AKG K371 | 32 Ω | 99.1 dB/mW | 1.2 mW | +16 dB | Comfortable damping |
| Audio-Technica ATH-M50X | 38 Ω | 99.0 dB/mW | 1.3 mW | +15 dB | Comfortable damping |
| Beyerdynamic DT 900 Pro X | 48 Ω | 100.0 dB/mW | 1.0 mW | +16 dB | Comfortable damping |
| Audeze LCD-2 Classic | 70 Ω | 101.0 dB/mW | 0.79 mW | +16 dB | Comfortable damping |
| Grado SR80x | 38 Ω | 98.0 dB/mW | 1.6 mW | +14 dB | Comfortable damping |
| Sennheiser HD 560S | 120 Ω | 100.8 dB/mW | 0.83 mW | +16 dB | Comfortable damping |
| HiFiMAN Edition XS | 18 Ω | 92.0 dB | 6.3 mW | +6 dB | Enough damping |
| HiFiMAN Arya Stealth | 32 Ω | 94.0 dB | 4.0 mW | +11 dB | Comfortable damping |
| Dan Clark Audio AEON 2 Closed | 13 Ω | 90.0 dB/mW | 10 mW | +3 dB | Marginal damping |
| Audeze LCD-5 | 14 Ω | 90.0 dB/mW | 10 mW | +3 dB | Marginal damping |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 102.0 dB/mW | 0.63 mW | +16 dB | Comfortable damping |
| HiFiMAN HE400se | 25 Ω | 91.0 dB | 7.9 mW | +6 dB | Enough damping |
| HiFiMAN Sundara | 32 Ω | 92.0 dB | 6.3 mW | +9 dB | Enough damping |
| Dan Clark Audio Stealth | 23 Ω | 90.0 dB/mW | 10 mW | +5 dB | Enough damping |
| Fostex T50RP MK3 | 50 Ω | 92.0 dB/mW | 6.3 mW | +8 dB | Enough damping |
| AKG K702 | 62 Ω | 92.9 dB/mW | 5.1 mW | +8 dB | Enough damping |
| ZMF Verite Closed | 300 Ω | 99.0 dB/mW | 1.3 mW | +13 dB | Comfortable damping |
| Sennheiser HD 650 | 300 Ω | 97.8 dB/mW | 1.7 mW | +12 dB | Comfortable damping |
| Sennheiser HD 800S | 300 Ω | 96.8 dB/mW | 2.1 mW | +11 dB | Comfortable damping |
| Beyerdynamic DT 770 Pro (250Ω) | 250 Ω | 96.0 dB | 2.5 mW | +10 dB | Comfortable damping |
| Audio-Technica ATH-R70X | 470 Ω | 98.0 dB/mW | 1.6 mW | +10 dB | Comfortable |
| ZMF Atrium | 300 Ω | 96.0 dB/mW | 2.5 mW | +10 dB | Enough damping |
| Abyss AB-1266 Phi TC | 50 Ω | 88.0 dB/mW | 16 mW | +4 dB | Enough damping |
| Sennheiser HD 600 | 300 Ω | 91.8 dB/mW | 6.6 mW | +6 dB | Enough damping |
| HiFiMAN Susvara | 60 Ω | 83.0 dB | 50 mW | -1 dB | Not enough damping |
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.
At 51.5Ω output impedance, the one-eighth rule says this source suits headphones of 412.0Ω and above. 561 of the 567 models here fall below that. That is most of the database, not a niche — 222 of them multi-driver in-ears, and the mismatch tilts the frequency response audibly rather than subtly.
| 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 |
| iFi GO link | USB dongle | $59 | 14 mW | 0.4 Ω | not published |
Of the 280 sources here, 40 do everything the Tascam US-4x4HR 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 FiiO KA11 at $29, against this one’s $249 — $220 less, and a USB dongle rather than an audio interface.
The cheaper one also publishes a noise figure, which the Tascam US-4x4HR 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.
$249 · 22 mW into 32Ω · 50 Ω out
Compare →$250 · 27 mW into 32Ω · output Ω not published
Compare →$229 · 374 mW into 32Ω · 1 Ω out
Compare →$219 · 333 mW into 32Ω · output Ω not published
Compare →$279 · 55 mW into 32Ω · 11 Ω out
Compare →$279 · 333 mW into 32Ω · output Ω not published
Compare →Compared with its closest rivals: vs Apogee BOOM · vs Audient EVO 8 · vs Focusrite Vocaster Two · vs SSL 2 MkII · vs Tascam US-2x2HR.