like many things the difference is marginal. however the XSUM is shockingly transparent. the xtramix has many layers of more electronics in the signal path. you just cant get around that changing the sound. xtramix is very close. i also have an older xtramix version so i cant comment on the latest revision.
Originally Posted by Ghost Logic
Did you a/b it with the Xtramix? I suppose its closer to a "straight wire" than the Xtramix but it seems shocking to me that there would really be that much of a difference between the two, particularly since the LiLO is basically a console version of the Xtramix--why base your high end mixing console on an inferior design? What version of the Xtramix did you compare the Xsum to (there have been five revisions of the Xtramix and I understand there have been significant component/sound upgrades over the years).