The Screen:
Small and easy to read, good contrast. Poor maximum brightness.
User Interface, Navigation/Operation:
The xDuoo interface cannot handle 16 Bit 44.1 kHz files correctly (they’re played back too slowly), so I installed the alternative firmware Rockbox that I’ve also got on my SanDisk Sansa Clip + and Sansa Clip Zip on the X3, so I’m already used to that interface as well. Volume control is precise with 1 dB steps over the entire attenuation range and gapless playback works perfectly.
Since the X3 has got plenty of individual buttons, navigation and operation remain quite easy.
The only drawback about installing Rockbox on the X3 is that all of the inserted micro SD cards have to be FAT32-formatted in order to work.
Battery Life:
Tested w/ Rockbox firmware, Superlux HD668B, Volume @ -53 dB, 16 Bit 44.1 kHz file played in a loop, occasional unlocking and navigation through menus: 11 hours, 55 minutes.
Sound:
Frequency Response, no Load:
Headphone Output:
→ Just as straight and linear as it should be.
Line Output:
→ ~ 1 dB sub-bass roll-off – not as nice as a straight line but negligible.
Frequency Response, loaded (Ultimate Ears Triple.Fi 10):
→ Splendid. Pretty much no deviation indicates an output impedance of around tiny 0.1 Ohms and no roll-off in the lows (as it would happen with wrongly dimensioned coupling capacitors), therefore xDuoo’s X3 will drive any critical multi-BA in-ear without altering its sound.
Hiss:
Noticeable hiss using sensitive in-ears. Not as hissy as some other sources, but still not the best pairing with very/extremely sensitive in-ears.
Subjective Sonic Impressions:
Appears mostly as clean, transparent and spacious as a DAP should sound if it’s not poorly constructed. Slightly softer bass response using well-resolving in-ears, though. Treble (violins, cymbals) perhaps just a tad not as clean (as if there were some artefacts, minor distortion or whatever, perhaps caused by the hiss). Only during very critical comparative listening though (→ not an obvious characteristic).
Bias and imagination cannot be excluded.
Conclusion:
Relatively inexpensive, each button has its own function (although the layout/design may be slightly odd), two micro SD slots, alternative Rockbox OS can be installed, commendably low output impedance, somewhat (too) hissy using sensitive in-ears.
