The emulator documentation says:
  -audio-in <backend>   Use the specified audio-input backend.
It also says that
  -help-<option>    Print help for a specific startup option.
Which means that -help-audio-in should list available backends.
But when I type "emulator.exe -help-audio-in" I receive:
  unknown option: -help-audio-in
  please use -help for a list of valid topics
Well, when I type ""emulator.exe -help" I receive the same information as in the documentation:
  -help-<option>    Print options-specific help.
This is a catch 22 situation... How do I get the list of audio "backends" for the emulator in Windows?