muddy sound from UR22 mkii line out

connected both windows 10 and mac with Mojave via the USB to the UR22. in both cases recent drivers installed (v1.10.4 windows and v1.10.5 for mac) and firmware up to date. Sound via both the headphones and line out from the ur22 is significantly poorer quality/“muddy” than headphone socket on either of lap tops using the inbuilt drivers. Any ideas on where else to start investigating the problem welcome. Music being played from iTunes in this case.