Both are desktop DAC/amps, $100 against $143. 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 FiiO K11 reaches 100 dB on 567 of the 567 models here, the Creative Sound Blaster X3 on 553.
| Specification | Creative Sound Blaster X3 | FiiO K11 |
|---|---|---|
| Power into 32Ω | 45 mW | 520 mW |
| Power into 150Ω | 35 mW | 115 mW |
| Power into 300Ω | 21 mW | 60 mW |
| Power into 600Ω | 14 mW | 30 mW |
| Output impedance | not published | 1.2 Ω |
| Output noise | not published | 2.8 µV |
| Price | $100 | $143 |
| Headphones it reaches 100 dB on out of 567 | 553 | 567 |
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.
14 headphones reach 100 dB on the FiiO K11 but not on the Creative Sound Blaster X3 — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 11 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: Creative Sound Blaster X3 and FiiO K11. Or put either against your own headphones in the source comparison tool.