I've seen a number of consumer bt speakers that are advertised as having a "stereo mode", where two identical units can be paired for a stereo setup. Since this is not available on every speaker on the market, it's clearly some modification to "stock" Bluetooth. But, is it a "firmware" modification or a "hardware" modification? Meaning, can I buy any devkit that will let me prototype this functionality?

Bonus points if I can connect and "mix" more than 2 speakers.

Thanks so much

Joe

 

I would mod a stereo bluetooth speaker and provide a signal out for additional amps.

 

You can use ESP32-A1S Audio Kit : https://docs.ai-thinker.com/en/esp32-audio-kit