Now I find no error when I use a semicolon to suppress display of the Audio object:
testAudio = Audio[{testSeries, testSeries}, SampleRate -> mySampleRate];
That is likely how I got Audio[] to work yesterday morning, but I hadn't figured that out until now.
If I subsequently attempt to display the Audio object, the error occurs. After the error, if I use Ctrl-Shift-E to view the underlying display-code, I find this. I don't know what to make of it, but maybe someone more expert will find it significant:
Cell[BoxData[
TagBox[
DynamicModuleBox[{Audio`AudioObjects`audio$$ = HoldComplete[
Audio[RawArray["Real32",{0., 1., 0.}], "Real32", Appearance -> Automatic, AudioDevice -> Automatic,
SampleRate -> 48000, SoundVolume -> 1]], Audio`AudioObjects`audioID$$, Audio`AudioObjects`buttonState$$ =
"Basic", Audio`AudioObjects`newAudio$$},
DynamicBox[ToBoxes[
Audio`AudioGUI[
1, Audio`AudioObjects`audioID$$, Audio`AudioObjects`buttonState$$, Audio`AudioObjects`audio$$],
StandardForm],
ImageSizeCache->{42., {6., 11.}},
TrackedSymbols:>{}],
Deinitialization:>Clear[Audio`AudioObjects`newAudio$$],
DynamicModuleValues:>{},
Initialization:>({Audio`AudioObjects`newAudio$$, Audio`AudioObjects`audioID$$} =
Audio`CheckID[Audio`AudioObjects`audio$$, Audio`AudioObjects`audioID$$, Audio`AudioObjects`newAudio$$]),
UnsavedVariables:>{Audio`AudioObjects`audioID$$, Audio`AudioObjects`newAudio$$}],
Audio`AudioBox[],
Editable->False,
Selectable->False]], "Output",
CellChangeTimes->{3.6976615171857677`*^9}]
P.S. And now, after restarting Mathematica, it's working fine even if I omit the semicolon. At this time I'm unable to reproduce the error. I don't believe this was a case of user-error, though. Something is not right with Audio[].
P.P.S. And most recently, it Audio[] has become dysfunctional again on my system, and I know of no way to fix it.
