If you have a truly mighty soundcard with a lot of channels you probably wondered what all the sliders are all about. Now the time of asking is over. KMix does now tell you exactly whether you are operating Subwoofer or Front if you split a control. This feature will ship with KDE4.8.
This is an example of a cheap USB soundcard. As you see, today even cheap cards support 7.1 channels on one control.
Noteworthy is also the PCM control.Without labels you might miss that PCM on this card is a capture device only.