This is the frontend for mixer settings delivered together with the Xfce4 desktop environment. It does the same jobs other mixer frontends do but is integrated into the Xfce4 desktop as a plugin for the Xfce4 main panel.
xfce4-mixer-alsa | Xfce4 Mixer ALSA backend | Mehr ...
This is the ALSA backend for xfce4-mixer.
xfce4-mixer-oss | Xfce4 Mixer OSS backend | Mehr ...