I've found what appears to be a bug with the Audio Source block when using dual outputs.
This can be replicated very simply by attaching a dual output Audio Source block to a Wav File Sink, it always results in the following error:
ValueError: port number 1 exceeds max of 0
The only solution I've found was simply "use linux", but this isn't really acceptable for my use case.
Any help would be greatly appreciated.
With regards,
Charlie