definition of balanced mode vs. single ended

Balanced means both signals float with respect to ground. Single ended means that the negative side of the signal is circuit ground. Balanced usually has better noise rejection and therefore less noise....although the difference in home audio is subtle (in a studio where one is mixing all kinds of signals, with long signal paths, and often applying large gains then balanced circuitry is much preferred)

Why is this called balanced.... the idea is that both signal paths are nearly identical and therefore any stray noise is expected to affect both signal paths in an equal or balanced manner and thus will not affect the signal (difference between both balanced paths both affected by same stray noise = zero)

Equipment that is "fully balanced" inside has duplicate amplifiers such that the + & - legs of the circuit are phase-inverted and referenced separately to a common ground. When the inverted phases are summed together at the end of circuit, noise from one side cancels noise from the other (achieving "common mode noise rejection"). This offers greater signal-to-noise ratio relative to a single-ended circuit utilizing one amplifier of comparable quality. The fully balanced circuit with twice the components is of course also more expensive. The cable has three pins & a shield, not five as mentioned by Ehart.

Four conductors (counting the shield and ground) -- isn't that the same as what Dgarretson said? It's true that not all 5 pins on the connector are used.

Great explanations of balanced from dgarretson and shadorne.

As I was reading a article in a audio magazine what was described as being balanced was that both speakers would have equal sound and as where single ended sometimes is unbalanced meaning one speaker is louder than the other. Would anybody like to comment on this?