LG G2 D802 - How to increase volume level in Lineage OS

You can just turn up the volume by changing the standard volume using the standard CM File Manager in root mode or with adb terminal :

Open terminal and send:

• adb root
• adb pull /system/etc/mixer_paths.xml

edit the file with your favorite editor like this:

• <path name="speaker">
•     ...
•     <ctl name="RX7 Digital Volume" value="69" />
• </path>

go back in your terminal and send:

• adb remount
• adb push mixer_paths.xml  /system/etc/mixer_paths.xml

Just change, save, reboot and test.

This worked great for me. 

Changed the speaker volume as well as the in-call as well.