Thank you! That’s very helpful. The only concern is that the audio is not just speech. At least one channel will be music.A Bluetooth transmitter will not have an audio input impedance of 8 ohms or 16 ohms which is a speaker impedance. Instead its input impedance will be 10k ohms or more.
An audio coupling capacitor value is not calculated to pass frequencies higher than you can hear. Instead it is calculated to block DC and very low frequencies that you cannot hear. You want the coupling capacitor to pass audio frequencies.
I assume your audio is speech which goes as low as about 50Hz. Then a coupling capacitor value to pass audio frequencies above 50Hz into 10k ohms is 1 divided by (2 x pi x 10k ohms x 50Hz)= 0.32uF. Use a 330nF film capacitor.
Your calculation examples and the typical impedance of a BT transmitter are critical data points.
Thanks again.