Thanks ConstantFlux and Adrian:
VLC works for me.
However, I've never heard of VLC before today. I'd be surprised if many had.
This does show that the audio information is in the files, but not accessible to the players I've used before VLC.
I tried VLC's conversion feature to produce an MP4. That worked, but the audio was again only audible when the MP4 file was played by VLC.
How do we get OBS Studio to record audio that any player can reproduce?
I appreciate the assistance you have provided.
Larry