Sound Amplifier is an app that enables an Android phone (definitely Pixels, unsure about others) to act as a remote microphone. I’d tried it previously with ASHA hearing aids and it simply won’t work unless you plug in a headset. It does, however, work with my Philips Hearlink 9050s IF LE Audio is enabled for that connection.
Latency seems fine. There’s no discernable echo effect with both the phone’s and hearing aid’s microphones picking up the sound. So far I’ve put the phone under my tv and gone into another room and managed to follow the dialogue slightly better than I would if I were in the same room as the tv (which is not very well). You do get the echo of the room tbough.
Not having a social life, I haven’t yet tested it in a restaurant environment.
The app can switch between directional and omni modes. There’s a noise reduction switch and slider. There’s a ‘Boost’ switch and slider for soft sounds. There’s a tone slider for low/high frequency boost. You can adjust both ears together or individually.
If nothing else, it’s a proof of concept of sorts. Anyway, have fun with it and report back.