I've installed CM 12.1 nightly (currently nightly 20151013) and people who call me complains that they have an echo, and they hear them selves. I already tried the following: 1. Update Nightly (started at 20151008) 2. Doing a fresh install clearing all cache. 3. Flashing the modem with different versions (currently i9500XXUBMG9) 4. Stop "Ok Google" 5. Changing the voice recognition to "Basic Google recognition" 6. Try different ROM (PAC Man) 7. Edit the build.prop and modify the `persist.audio.fluence.voicecall=false` I'm 90% sure that the problem is with the noise cancellation, because when I mute my mic the echo on the other side stop. This problem did not occur on the stock (4.2.2) I had before moving to CM. On the stock ROM I had an option to enable/disable the noise cancellation, this feature seems to be missing on CM12.1 ROM. Do you have any suggestions? Do you know how to enable/disable the noise cancellation? Thanks, Liron