Direct Decoding (a.k.a. decoded by dbPowerAmp):
total harmonic distortions
As you can see, OGG generally measures pretty bad. Nevertheless, all formats are decoded to 32 bit floating point - this is the result. Apart from the original WAV file MP3 & AAC would be able to encode with high resolution (meaning: better than CD).
I have been saying OGG had issues since I got my x3. That was well before most people outside of Asia. Sadly I felt a little brushed off by James on that issue.
It's good to see I was not imagining it :)
I am not having a go at Fiio or James. I still love the x3 and James has done an outstanding job supporting our requests. I just guess OGG was a minority used format, so I swapped to FLAC.