Short answer
Both are audio interfaces, $250 against $249.
The Tascam US-4x4HR reaches 100 dB on 553 of the 567 models here, the Focusrite Vocaster Two on 550.
| Specification | Focusrite Vocaster Two | Tascam US-4x4HR |
|---|---|---|
| Power into 32Ω | 27 mW | 45 mW |
| Power into 150Ω | 10 mW | 36 mW |
| Power into 300Ω | 7.7 mW | 24 mW |
| Power into 600Ω | 3.8 mW | 14 mW |
| Output impedance | not published | 51.5 Ω |
| Output noise | not published | not published |
| Price | $250 | $249 |
| Headphones it reaches 100 dB on out of 567 | 550 | 553 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Focusrite Vocaster Two | Tascam US-4x4HR |
|---|---|---|
| 32 Ω | Derived | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Derived | Derived |
Only one of these two columns starts from a power rating. Tascam US-4x4HR publishes one at 32 Ω; Focusrite Vocaster Two publishes none at any of these four loads, so its column is worked out from power it published at other loads. Both are arithmetic on a maker’s own figures rather than guesses, and the method used for the Focusrite Vocaster Two understates rather than flatters — but at 32 Ω is the only load here at which its maker can be held to a figure.
3 headphones reach 100 dB on the Tascam US-4x4HR but not on the Focusrite Vocaster Two — HiFiMAN Susvara Unveiled, Kinera Freya Vanir, Thieaudio Hype 10.
550 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 Audio-Technica ATH-R70X: Tascam US-4x4HR has +10 dB of headroom there against +5 dB. 5 dB is about 3.4 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Focusrite Vocaster Two and Tascam US-4x4HR because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Focusrite Vocaster Two headroom | Tascam US-4x4HR headroom | Focusrite Vocaster Two hiss | Tascam US-4x4HR hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +23 dB | +25 dB damping | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +3 dB | +5 dB damping | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +13 dB | +16 dB damping | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +11 dB | +16 dB damping | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +4 dB | +6 dB damping | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +5 dB | +10 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +1 dB | +6 dB damping | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | -5 dB | -1 dB damping | not published | not published |
The Focusrite Vocaster Two costs $1 more than the Tascam US-4x4HR, and on these three axes the money buys nothing: among the 567 models here there is not one that the Focusrite Vocaster Two handles and the Tascam US-4x4HR does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper Tascam US-4x4HR drives 3 models to 100 dB that the Focusrite Vocaster Two does not.
Only published figures count here; blank axes are counted separately.
Each in full: Focusrite Vocaster Two and Tascam US-4x4HR.