DoubleJ,
Yep, that did it. The choices there are "Hi mp3" or "Low mp3" (or WWOZ 2) and it is indeed playing Hi mp3. I wonder if playing it through TuneIn in the main rig is harming the stream... I don't listen much on the phone at all, so I'll still have to do some tinkering with how to make it sound better in the listening room. I just don't know how to get it from the phone or iPad to the LUMIN other than via TuneIn in the LUMIN App.
A short listen on the phone tells me that it does sound pretty good, though - in line with other sources.
Thank you kindly, and Happy Thanksgiving to you and yours!