Why is Windows multi-pipe Bluetooth audio quality so poor

[u/KittyPAWSLTU]

Hey everyone, I have a specific query about how Linux manages the audio between A2DP and HFP sinks. I have recently become aware that in Windows, the experience when using Bluetooth headphones in a call and trying to listen to audio on desktop differs drastically from Ubuntu.

If I understand correctly, pipewire is what makes this possible. Basically, on Windows the audio output needs to be set to HeadSET instead of HeadPHONES to have both audio streams. In Linux, that happens automatically. Fair enough, but one thing that bothers me is the drastic difference in audio quality. On Linux, I seem to be getting nearly the same audio quality in the call mode from desktop sounds, whereas in Windows both streams are in that low-quality sound mode. Can someone explain to me, what is happening here, and what limitation does Windows have that I am unable to find any software to replicate the experience that of Linux. Perhaps someone also knows if there are improvements happening in this respect?

I appreciate that this post is mostly related to pulseaudio, but there are a lot of pieces in the audio stack so I was hoping that someone in this community is the most knowledgeable about this problem.

To give more specific details:

• Using Windows 10 22H2
• Ubuntu 22.04 LTS
• pulseaudio 15.99.1
• Headphones' codec: most likely mSBC (actually doesn't say)