Poor sound quality when recording from XDJ RX3

I've just bought an RX3 and find that the sound is really poor when I record a live mix via the USB 2 port (MASTER REC function).
The sound seems compressed, flat... Especially in the treble and medium, where it's clearly lacking. What's more, to get more or less the same volume as the original tracks, I have to push the TRIMs of each track into the red, or at least dark orange (levels between 6 and 12 on the indicator lights).
I'm on version 1.15, controler is brand new and my sounds are of excellent quality (wav or flac).
It seems that versions 1.16 or 1.17 are even worse, reading the comments on Reddit...
Considering the price of the device, I'm really disappointed.
Recordings made with my DDJ T1 dating from 2010 were of much better quality, this is beyond comprehension!
It seems I'm not the only one complaining about this problem, @pioneer do you have an explanation/solution???