Hi guys. I managed to enable dual speaker mod
on OnePlus 3T (didn't tested on OnePlus 3, but I think is working) with HavocOS 2.7 build 01.08.2019 and is working good. It should work with ROMs based on LineageOS, didn't tested on OxygenOS since LOS team changed some things in mixer_paths_tasha.xml.
LINK (MIRROR): URL
1. First backup
your original mixer_paths_tasha.xml
by renaming it to mixer_paths_tasha.xml.bak
2. Copy mixer_path_tasha.xml (modded one) to /system/vendor/etc
3. Reboot and profit
Please test and report if you having issues!
Magisk version coming soon!