Знатоки звуковой подсистемы Linux-а, объясните кто виноват. Имеем регулировку громкости в Ubuntu 16.04 с Openbox-ом в rc.xml такого вида:
<!-- Keybindings for sound control -->
<keybind key="XF86AudioRaiseVolume">
<action name="Execute">
<command>amixer -D pulse set Master 2%+ unmute</command>
</action>
</keybind>
<keybind key="XF86AudioLowerVolume">
<action name="Execute">
<command>amixer -D pulse set Master 2%- unmute</command>
</action>
</keybind>
<keybind key="XF86AudioMute">
<action name="Execute">
<command>amixer set Master toggle</command>
</action>
</keybind>
<!-- Keybindings for sound control -->
<keybind key="XF86AudioRaiseVolume">
<action name="Execute">
<command>amixer -D pulse set Master 1%+ unmute</command>
</action>
</keybind>
<keybind key="XF86AudioLowerVolume">
<action name="Execute">
<command>amixer -D pulse set Master 1%- unmute</command>
</action>
</keybind>
<keybind key="XF86AudioMute">
<action name="Execute">
<command>amixer set Master toggle</command>
</action>
</keybind>
Simple mixer control 'Master',0
Capabilities: pvolume pswitch pswitch-joined
Playback channels: Front Left - Front Right
Limits: Playback 0 - 65536
Mono:
Front Left: Playback 23597 [26%] [on]
Front Right: Playback 23597 [17%] [on]