Ticket #15598 (closed defect: fixed)
AC97 volume control is not linear [5.1 regression]
|Reported by:||mhanor||Owned by:|
I have discussed the issue here
The guest volume control is off, when using the AC97 audio controller. I would expect a linear control, but that's not the case. I consider it to be a regression in 5.1, as I have never had this kind of problems with previous versions, 5.0.xx and older. It manifests on my Windows 10 x64 host and on my Ubuntu 16.04 x64 host (running on the same PC).
As an example, on my Ubuntu host, using VirtualBox 5.1 (release) to run Ubuntu 16.04 x64 (live) as a guest. The host's Master volume control is set to 100%. Using amixer from the guest's terminal to change the guest Master volume control (e.g. amixer sset 'Master' 100%), there is no difference in sound intensity when modifying the guest's Master volume control anywhere in the range 71-100%, including the limits of this range (which seems to set the maximum intensity). Only when setting to 70%, I can hear a drop in sound intensity. On the other hand, any value below 58%, it's almost mute (I almost can hear something at 58% Master volume setting, but I have good hearing). At 59%, the sound can definitely be heard, at a very low intensity. The same is with Windows as host, the difference is an offset, meaning that, at 50% guest volume setting (using the same guest), I definitely can hear something at a very low intensity. Also, I haven't identified any differences when changing the Host Audio driver (from PulseAudio to ALSA), when using the Ubuntu host.