Send audio from one Pi to another Pi, and the "2nd" Pi working as bridge sending audio to next Pi and so on, each "2nd" Pi as a wifi router to the next Pi and so on also.
I want to make a low cost speaker system for demonstration/protest, the master Pi mainly for speech through microphone as input device, and there are many slave Pi in 2nd, 3rd, 4th … n-th level. The n-th Pi will get “speech” from (n-1)-th Pi, then this “speech” will output through speaker and transmit to (n+1)-th Pi.
Wifi or bluetooh is ok, but I think wifi can send longer distance. I am thinking adding a UBS wifi on each Pi, so that the build-in wifi to receive data, and the USB wifi to transmit data. We can fix the local IP for each Pi, and the source wifi ssd, password and IP etc.
The master Pi can select audio source from microphone, or play an mp3 file (selection through web page or touch panel). If possible, people that joining the demonstration/protest can use their smart phone connecting to the nearby wifi source to hear the speech.