Hi! Many people have complained about not being able to hear person X in voice chat, because their voice is too low. If turning the outbound volume to 250% isn't enough, I'm happy to provide a cure for this disease! With the following command, you can set the outbound volume as high as you want.
/console SET OutboundChatVolume "5"
That 5 there means the outbound volume will be set to 500%, feel free to change it to suit your needs. I hope this helps
PS. There is also a variable called InboundChatVolume, but unfortunately I haven't noticed any change by setting it over 1 (100%).