Short answer
Both are audio interfaces, $299 against $250.
The Apogee BOOM reaches 100 dB on 565 of the 567 models here, the Focusrite Vocaster Two on 550.
| Specification | Apogee BOOM | Focusrite Vocaster Two |
|---|---|---|
| Power into 32Ω | 240 mW | 27 mW |
| Power into 150Ω | 51 mW | 10 mW |
| Power into 300Ω | 26 mW | 7.7 mW |
| Power into 600Ω | 13 mW | 3.8 mW |
| Output impedance | 0.5 Ω | not published |
| Output noise | not published | not published |
| Price | $299 | $250 |
| Headphones it reaches 100 dB on out of 567 | 565 | 550 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Apogee BOOM | Focusrite Vocaster Two |
|---|---|---|
| 32 Ω | Published | Derived |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Derived | Derived |
Only one of these two columns starts from a power rating. Apogee BOOM 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.
15 headphones reach 100 dB on the Apogee BOOM but not on the Focusrite Vocaster Two — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 12 more.
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 HiFiMAN HE400se: Apogee BOOM has +14 dB of headroom there against +4 dB. 9 dB is about 8.8 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Apogee BOOM and Focusrite Vocaster Two because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Apogee BOOM headroom | Focusrite Vocaster Two headroom | Apogee BOOM hiss | Focusrite Vocaster Two hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +32 dB | +23 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +12 dB | +3 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +21 dB | +13 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +17 dB | +11 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +14 dB | +4 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +10 dB | +5 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +6 dB | +1 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +4 dB | -5 dB | not published | not published |
The Apogee BOOM costs $49 more than the Focusrite Vocaster Two. Out of the 567 models here, that difference buys 15 more models driven to 100 dB.
Nothing runs the other way: there is no axis here on which the cheaper of the two does better.
Only published figures count here; blank axes are counted separately.
Each in full: Apogee BOOM and Focusrite Vocaster Two.