So this is kind of a complex question. Neither of us have hearing problems (I have tinnitus but it is more of an annoyance than an impedance) so we exclusively use them for the active noise cancellation (reducing world volume) and not for the world volume boost. The directional noise cancellation and microphone directivity works quite well for us but I cannot really speak to how well the world volume boost works since I don't have an easy way to measure its effectiveness.

My only criticism is that they use HSP during phone calls, then switch back to A2DP when music/audio resumes. This means that audio quality during phone calls is significantly worse than normal audio output, but this occurs with every bluetooth headset I have tried.

HSP/HFP for calls is very standard; A2DP isn't suitable for calls since it's unidirectional. HFP 1.6 supports wide band (16khz) speech with the mSBC codec, which is a big improvement, but adoption has been very slow.

E.g. in Android, I think Oreo finally added some HFP 1.6 support, and 16kz SCO output should be theoretically possible (I wasn't able to get it to work). But for some reason, 8khz SCO input remains explicitly unsupported, as per the AudioManager doc:

> "The following restrictions apply on [SCO] input streams: [...] the sampling must be 8kHz"

From what I've seen, most bluetooth devices and cellular providers don't seem to support 16khz speech either. At this rate, it seems like most of us won't enjoy wide band bluetooth calls until 2030 or so.