Actually, both unbalanced cables and Balanced carry AC current (audio) and so they both have a bit of out of phase happening. Unbalanced wires carry high impedance (lots of resistance) loads. Alternating current is flowing down both the ground wire, which is a usually a mesh surrounding an inner wire. The phase of the two conductors is always opposite because its AC (push and pull). So to sum up unbalanced, one of the signal wires is acting as the ground and this is why it is a victim of noise. Balanced on the other hand uses a ground wire that is unassociated with the audio wires. It is usually a foil or wire mesh that surrounds the inner 2 wires. Balanced cables can go a longer distance without noise because they have a lower impedance (can be thought of as less resistance), the conductor wires are usually twisted or braided together to cancel noise and the shielding (ground) is not carrying audio signals, but is rather connected to the Earth ground. Balanced cables require transformers, both input and output on either end in order to function. This is because all gear is basically unbalanced on the inside (the guts). Transformers convert the long balanced cables to unbalanced for the circuitry in your gear. Microphones have built in transformers that convert the microphone’s unbalanced signal to balanced so you can go long cable runs without noise.
Just my 2 cents.
Very cool! And yes, you did explain it really well. I never quite understood the difference before now. 🙂