Awesome

actos-soundmenu

Very simple Sound Menu plasmoid with volume and playback (MPRIS) controls for the current media player.

Meant to be used as a lightweight replacement for the default KMix systray plasmoid.

After installation, you can enable it in the System Tray settings, under Extra Items.

Run with

plasmoidviewer

Install it on the KDE Plasma Desktop using the Get New Widgets dialog, from Add Widgets.