Unfortunately I confirm I have phone echo issues with this Rom since I installed it (fews months ago), and with every following update.
The echo is not on my side, my caller can hear it's own echo on his side. Seems like my mic is recording sound from my speaker (at low level but still)
Is there mixer_path tweaks to try, or something else to flash ?
Or is it possible to check another Rom mixer path file ?
I'm having this same issue. It seems that apps that don't rely on some form of phone call service/voIP (like the Google Recorder app) work just fine with the microphone. I can't hear anything that seems out of the blue, only the fact that the microphone (at least from what it seems) records audio a lot quieter than it use too.
The quiet microphone sensitivity seems to also carry over to the VoIP / Regular Calling apps as well. The Interlocutor can hear their voice briefly for a small amount of time shortly after they speak.
I think the reason why this happens is because the S7 has 2 microphones on the top and bottom. I noticed that the top microphone (at least from my findings with settings pages, and different apps) cannot be configured for use. The default microphone the phone uses is the one at the bottom, located close to the speaker.
I tried looking around many places (including XDA) in different places from Magisk Modules to Lineage updates, but it appears that this is a known issue with very minimal knowledge as to what is causing it for some people.
I hope this gives insight to anyone actively investigating the issue, though I do admit it's pretty surface level observations.
Thanks to everyone for making this possible, especially Ivan Meler.
(I'm using the Canadian G930W8 variant of the S7 in case anyone was wondering)
Edit: I forgot to mention that I tried installing different Microphone mixer_path patches, alongside having AML (Audio Modification Library) installed, but it seemed to not resolve anything. I will likely continue my own digging with this as I'm not too accustomed to what it fully does yet.