enableSeparateRecognitionPerChannel property
This needs to be set to true explicitly and audioChannelCount > 1 to get each channel recognized separately. The recognition result will contain a channelTag field to state which channel that result belongs to. If this is not true, we will only recognize the first channel. The request is billed cumulatively for all channels recognized: audioChannelCount multiplied by the length of the audio.
Implementation
bool enableSeparateRecognitionPerChannel;