Poor audio/boosted background



I've recently started using openPHT as it works with the Amazon Echo as well as my Mac Mini remote control (volume).

However I've noticed that the audio is extremely poor. There's a constant droning noise in the background on all formats whether it's a TV show, a movie or music. It's almost like any kind of background noise - traffic, people chatting, etc - is being amplified by factor of 100.

I've switched back to Plex home theatre and Plex Media Player and listened to the same TV shows and the same movies to compare and the backgrounds are near silent in comparison.

It's rendered open pht completely useless to me. Does anybody have any idea what would be causing this?

Plex Server v1.12.2.4929 (has been claimed)
Mac mini 2011 running El Capitan which runs plex home theatre and plex media player perfectly.
Analog audio out from the Mac to an external amp.