Aurender N10 - Sound quality performance is erratic

I am having problems with my N10. Some days it plays amazingly good, other days good and some days not good at all.

I live very near Aurender in SoCal and so I took my unit in for service and they provided me with a loaner. The first session after I put the loaner in the system was all-time good. Then the next day wasn't all that great. Then the next two days were good but no great. Anyway, this is just weird. Both N10s appear to exhibit this erratic behavior.

My internet is ATT DSL at 24Mbps and that has been suggested as the culprit (I was thinking about calling and asking them to give me a trial at 50 or 100 Mbps to see if the increased speed will eliminate the problem - 24Mbps is fast enough I almost never seen buffering in Netflix). It has been suggested that I get hi-speed cable to solve this problem and get rid of the twisted pairs on the phone line. I have tried a DSL filter and it hasn't seemed to help, assuming I've got it installed correctly.

So have any of you N10 users had this problem? If so, how did you fix it?