In the "Getting Started" section there is a topic created by @rockedge titled "Low Volume Fix", which I've just tried but didn't work initially.
Under method 2 it states to open terminal and enter "alsamixer -D equal", which I did. All I got was a load of error messages. Anyway, looking at the options it gave I changed it to "alsamixer -V equal" and it worked perfectly.
This was in Fossapup64 9.5 by the way. Thought this may be of help to anyone else left scratching their heads. Perhaps @rockedge could confirm that the D does need to be changed to V, and that it's not just me (not impossible).