The audio signal of the wav file is very weak, so there seems to be no signal.
If you amplify and play with audacity etc., you can hear the sound.
(refer attached file)
Why the signal is weak?
Since the audio file before separation is 8ch 2 speaker, if only 1ch 1 speaker’s voice is separated, the volume will be attenuated to 1/16 simply by calculating.
HARK Support Team