Well...inconclusive. It was definitely worse on the left. So I physically switched the speakers. Now it's mostly on the right but some can still be heard on the left. Its not constant. And, as I said, the Bluesound has boomier, deeper bass than the disk player (although disk player sounds great) and it is NOT noticeable when playing same song through CD at same volume on preamp (LOUD. But, again, different sounding DACs/marginally different outputs).
So I hav done 3000 songs saved on the BluOS app. Did someone say I would lose all that if I do a reset?
I want to do my best to understand what's going on and which component might be the culprit before contacting any tech support.