How to synchronize sound in bluetooth headphones?

Question

Do it yourself

Good day, I have an idea to collect my bluetooth headphones, but a small question arose.
Let's say each earphone will have a speaker, a microphone, bms, a battery and a bluetooth transmitter, how in this case to synchronize the sound between the first and second earphones, if the connection is made, for example , from phone

Answer 1

Without knowing the exact data of the microcontroller on which you are going to implement this, it is difficult to say. Each of the headphones actually works differently: one is the master, that is, it receives a stereo signal from the device, plays its own channel and transmits the other to the second. In modern models, the master and slave are determined automatically, so there is no disconnection when the master is turned off. There is a simpler scheme to implement - one earphone, for example, the right one, is strictly the master, and the device is connected to it. Accordingly, the left without the right becomes useless.
It’s a little unclear why BMS is needed if there is only one battery, and overdischarge protection is implemented by software methods. If the goal is not academic, then the idea is meaningless.