Inferior sound quality from UPnP

Hi All

My second post as I spend more time with my UnitiQute2.

Been doing some caparisons back to back and I have to say that tracks ripped through iTunes as Lossless ALAC files when played back via my wired network from my Synology DS214Play sound 'leaner' and with less depth than a 320kbps track steamed via and Airport Express/optical cable from Spotify.

Anyone had experience of this? Is it just settings on the Synology? (Looking at my attached device list on the Synology I have to use a 'generic dlna' profile for example). Is it iTunes as a ripping engine? I would say not... via the USB port again same tracks have more depth.

Any thoughts appreciated. I lived with it for a week now and I'm sure I'm not just imagining it!

Thank you in anticipation.