its not fixed on mine
as far as i know it was fixed in an update but then they unfixed in the update after that
im on the latest update+ custom firmware
I noticed the difference in sound volume on the HD channels also, I changed the setting in the Menu - Preferences - Audio for the Digital Audio Output from
Multi-Channelto Stereo and it's the same as all the other channels now, I wanted the best audio output but tbh it's fine like that for me.
If I remember this from last time the Multichannel / Stereo output volume thing is not possible to resolve - I can't promise a massively technical explanation so please bear with me but I think it goes along the lines of Stereo allows a volume change because the left/right channels are somehow seperate enough in the signal to allow the Humax to up or down them itself. However the Multichannel audio is too deeply embedded within the overall stream (picture and audio) so there's no way to tweak it up or down on it's own. I think at the time we had to assume that an external amp was expected (by Humax) if you wanted to make use of the full HD 5.1 multichannel audio so they took the route of just pumping out the audio at a fixed level and leave the volume control to the amp (or TV I guess?).hopefully there will be an update to some day that will solve it (like before), until then we'll just keep changing the volume