OK, did things.
Move the startRecording( ) from before, to after startPaying( ). I also fetched the latest buffered-SD audio source from h4yn0nnym0u5e.
Now when I do a fresh compile and load of code to the Teensy, the initial run produced an...
OK, I was able to put together a program to play a stereo wav file from an SD card, record it back as a stereo wav to another file on that SD card while outputting the initial file to the line out (of either the PT8211 or audio shield) - swiped...
Sorry if this is too obvious. I have searched the examples, forums, and some of the code libraries [could be just not seeing it] and am unable to find a complete, "simple" example of playing a stereo wav file from an SD card, running it through...