Testing Results for Kubuntu-KDE 15.10 Distribution. Original Problem report was issued from Edubuntu 15.10 Daily. I tried switching the Virtualbox Audio Hardware Driver from Pulse Audio to ALSA Audio consistent with results for the Edubuntu distribution. Monitoring alsamixer for Channel levels, using the Volume Slider on KDE does not Control the Master Audio out channels. I performed similar changes to my Lubuntu and Xubuntu Guests and received the same results as Kubuntu-KDE. To Restate, the only Distribution that I have a workaround to restore proper Volume Slider Control is Edubuntu. Altering Virtual Box Hardware Audio Drive from Pulse Audio to ALSA Audio has no effect on correcting Volume Slider's lack of controlling Master Out Channel(s) for Kubuntu-KDE, Lubuntu, & Xubuntu.. On Fri, Aug 21, 2015 at 1:20 AM, Gene Soo