If your soundbar has bluetooth it's most likely to have a receiver not a transmitter. But you don't really want audio from the soundbar to go to your headphones. You want sound from the TV to go to your headphones. You can attach a bluetooth transmitter to the TV. You would need one that has the correct input for the TV (most likely optical) audio output. You could split the output that connects to the soundbar so both it and the headphones would work at the same time.