There are 2 cases in creating transfer function depending on your setup.
Case1: Geometric transfer function
The position and the number of microphones that actually exists must be set in the HARKTOOL’s channel list. Since ReSpeaker Mic Array only has 4 microphones, it will create a 4-channel transfer function.
Case2: TSP transfer function.
The number of microphones used must be set in HARKTOOL’s channel list. But since the TSP sound recorded by ReSpeaker Mic Array has 6 channels, the WAV files input to HARKTOOL must exclude 0 and 5 channels beforehand. To do this, for example if you use a tool called ‘sox’, this can be done by executing the following command:
sox input.wav output.wav remix 2 3 4 5
Note that the channel number starts with 1 in sox, while in HARK it starts with 0.
In HARK, the 6 channels of data coming from AudioStreamFromMic can be filtered by using the ChannelSelector node in configuring the channels needed.
In your case, if you want to use the 2nd, 3rd, 4th, and 5th channels, you can set
<Vector<int> 1 2 3 4> in the ChannelSelector’s SELECTOR parameter.