It's just too bad that we have no crystal ball here, otherwise we would know what kind of hardware this is all about. If you are talking about analog audio on a Raspberry Pi, then you are totally correct. It is the achilles heel of the RPi boxes.
Using a Pi 2 here.. ... hdmi output is really weak.. haven tried the analog output.. I did do upgrade from openelec not a clean install to libreelec. (this might be the issue) Will try a clean instal now that i have some time.