Both are audio interfaces, $299 against $249. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?
The Apogee BOOM reaches 100 dB on 565 of the 567 models here, the Tascam US-4x4HR on 553.
| Specification | Apogee BOOM | Tascam US-4x4HR |
|---|---|---|
| Power into 32Ω | 240 mW | 45 mW |
| Power into 150Ω | 51 mW | 36 mW |
| Power into 300Ω | 26 mW | 24 mW |
| Power into 600Ω | 13 mW | 14 mW |
| Output impedance | 0.5 Ω | 51.5 Ω |
| Output noise | not published | not published |
| Price | $299 | $249 |
| Headphones it reaches 100 dB on out of 567 | 565 | 553 |
A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.
12 headphones reach 100 dB on the Apogee BOOM but not on the Tascam US-4x4HR — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 9 more.
560 headphones are left alone by the Apogee BOOM under the one-eighth rule but coloured by the Tascam US-4x4HR (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 557 more).
553 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Apogee BOOM and Tascam US-4x4HR. Or put either against your own headphones in the source comparison tool.