Sony WH-CH700N bluetooth poor sound quality in one mode, no sound in other

Solution 1:

I figured out the solution, helped by stumbling upon this answer. This could apply to other bluetooth headphones too.

1. Go to Settings > Devices, then on the right, click on "Devices and printers"

   

2. Right click on the headphones and click "Properties"

   

3. Go to the "Services" tab and, in my case, untick "Hands free Telephony"

   

I then had to turn off the bluetooth in Windows, then it on again and reconnect to the headphones. After that, the sound worked and was clear. I no longer got the "WH-CH700N Hands-Free AG Audio" option, only the "WH-CH700N Stereo" option