The Solution: Kill Gnome (Alt-SysRq-K) and play ogg file from terminal.
The Problem: An ogg file played with Audacity or with ogg123 sounded
terrible.
System is Jessie with standard debian packages installed
The ogg file was created from a cd with jack and was intended for an
sdcard for my car's entertainment system. I first played it from my
computer with Alsa line out to a fairly decent stereo system. The
playback was noisy, sounded like it was made from a worn out lp.
The cd played from my home entertainment system sounded fine. The ogg
file played from my car's entertainment system was ok.
What was wrong with my computer?
When a click from the stereo connected to the computer signaled the
arrival of an email I realized a computer sound system was running all
the time. What ever it is stopped when I killed Gnome.
Perhaps this is old hat, known to all. If so, there may be better
solutions than killing Gnome. If so, I would like to know these
solutions or be pointed appropriate discussions of the subject.