What is the difference between unbalanced and balanced? And how to choose them?

When building a sound system or a studio sound system, you may come across different types of audio cables for your equipment, such as XLR, RCA cable. They can be divided into the categories of "balanced" and "unbalanced" cables. What do these two terms mean? And what are the differences between them? By the end of this article, you will have a better understanding of these two types of cables and how to choose between them.

What is an unbalanced cable?

Unbalanced cables are cables that are commonly used to connect audio devices such as headphones and musical instruments such as guitars or bass guitars. Cables that have only one contact point for the shield and one signal are unbalanced. They consist of two conductors: a signal wire (the "Hot" wire) and a ground wire.

The signal wire carries the audio signal from the audio devices, and the ground wire serves as a reference point for the audio signal and also shields the signal from interference. However, they are more susceptible to noise and interference over long cable runs, which can result in an audible hum or buzz in your audio.

What is a balanced cable?

Balanced cables, on the other hand, have three conductors: two signal wires - "Hot" (positive) and "Cold" (negative), and a ground wire. The two signal wires carry the audio signal with opposite polarity, which helps cancel out any interference picked up along the way.

They are designed to minimize interference and provide the best sound quality over long distances, making them the preferred choice for professional audio applications.

How does balanced audio work?

So now we know that balanced cables use two signal wires (Hot and Cold), but how does that extra wire make the cable's length and noise rejection ability so much better than an unbalanced cable?

When a balanced cable receives a signal, both signal wires carry a copy of the signal, but the trick is that the two signals are sent with the polarity reversed. If you're new to audio, here's a new concept: if you combine two identical signals with the polarity reversed, the signals will be in "phase opposition" and the signal will cancel out, leaving you with complete silence - this is called "out of phase". (Think of positive and negative numbers added together: +10 plus -10 equals 0.)

So why would you want audio equipment that reverses the polarity of your signal? In this case, because the receiving equipment will flip the inverted signal back to its original orientation. But since both copies of the signal picked up the same noise during transmission down the cable — and that noise is identical on the two wires in the cable — reversing the polarity of what arrives at the receiving equipment will yield the original signal intact and the noise that is now in reverse polarity.

The summation produces the desired result: preserved signal and suppressed noise. Because of this, balanced cables can support much longer cable runs than unbalanced cables — about 300 feet (90-100 meters) at most.

Microphone wiring and interconnect cables between consoles, signal processors, and amplifiers in a professional sound system or studio recording environment are usually of the balanced type.

Types of Unbalanced Cables

RCA Cables

RCA cables are widely used for unbalanced analog audio connections. They typically consist of a red tip (right channel) and a white or black tip (left channel). Unbalanced RCA signals are best suited for short distances, typically less than 25 feet.

Quarter-inch TS Cables

Quarter-inch TS (tip, sleeve) cables are typically used for unbalanced signals, especially with musical instruments such as electric guitars or bass guitars connected to amplifiers. These cables provide a simple connection and are ideal for short-distance applications.