Thanks for that in the end this command did the job perfectly for me
amixer sset 'VIA DXS',0 80% 80%
when call directly from the command line but when i put it into a crontab
0 9 * * * root amixer sset 'VIA DXS',0 80% 80%
i.e. set the volume to 80% at 9 in the morning every day
but for some reason amixer
sets the volume to 100% but when i make the exact same call from the
command line it does as expected.
I have confirmed the crontab does execute the script as the volume was
set at 90% before the scheduled crontab but 100 afterwards.