Many bluetooth headphones support microphones with A2DP, though. And if yours do, you likely want to use that rather than HSP, because HSP has much worse audio quality.
> Each A2DP service, of possibly many, is designed to uni-directionally transfer an audio stream in up to 2 channel stereo, either to or from the Bluetooth host.
This matches what I has heard: Bluetooth devices with A2DP profile can either receive or send high-quality audio, but not both at the same time.
I don't know if there are Bluetooth headsets that have separate A2DP devices for input and output sound, I have never heard about them, but I would be very interested in knowing of their existence.
Also from the article:
> These systems often also implement Headset (HSP) or Hands-Free (HFP) profiles for telephone calls, which may be used separately.
This is the common case for Bluetooth headsets, the Bluetooth manager switches profile when the microphone is needed, but that greatly reduces audio quality.
What this setting does, is that when an application requests the Microphone, then it automatically switches to HSP, and once the source is destroyed, it switches back to A2DP.
When I am using the headphones, and IF an application requests microphone, THEN I do want this switch to happen automatically. After the Microphone is not needed anymore, I want it to switch back to the HQ A2DP.
HSP makes the headphone quality much worse, and mono. Even while using the mic, that's not ideal. You might not notice if you're just having a conversation, but if you're sharing a video or watching/playing a game, you want the audio output quality.
I understand the quality issue, of course I also notice it.
But how else would my mic work? If it stays on A2DP, then there is no Mic input, so I used to have to manually switch it to HSP. With the solution I linked above, this is not manual.
So... I am not sure it does support it, TBH. I have a Bose QuietComfort 35 (II), and on linux I definitely have the low quality HSP+ mic (other thatn the quality, works well) and for listening only, A2DP is working too.
On Android though, calls are _MUCH_ higher quality with the mic on. (still somewhat different than from output-only, but less degradation than under my desktop linux)
