A situation in which a
mass or system of masses is arranged in such a way that it's center of mass is not uniformly in the
center.
ex:: A vehicle with too much wieght on one side is unbalanced, and thus has control issues.
In the
studio, unbalanced cables are indeed a signal and ground. Why this is bad: the cable tends to pick up
electromagnetic interference. Whereas an
unbalanced line is specially designed to invert one of the signal paths as it flows down the cable. At the end where the cable plugs in, that line is re-inverted, and
super-imposed on to the original signal, cancelling out the noise that was added during the run of the cable.