Balanced Vs Unbalanced Audio Cables

Before you understand balanced and unbalanced cables, it is important to understand analogue and digital cables.

Analogue vs Digital Audio Cables

The first thing to learn is the difference between analogue and digital cable. Audio cables can be categorised into two broad categories -

1. Analogue Audio Cables
2. Digital Audio Cables

What's the difference between analogue and digital audio cables?

Analogue and digital audio cables both convey data. The major distinction is that digital cables convey digital information, i.e., binary code (zeroes and ones, the language that computers speak). Whereas analogue cables stream electrical impulses, i.e., voltage.

For example, an XLR Cable, which is commonly used to connect microphones, is analogue. On the other hand, a MIDI Cable, mostly used to connect a MIDI Device to a PC, is a Digital Cable.

It is fairly simple to determine whether you require an analogue or digital cable. If you are using analogue gear like a guitar, synth, microphone, bass etc., you need to use an analogue cable. If you are using digital gear like a MIDI keyboard, Digital mixer etc., you are required to use a digital cable.

Once you understand the basic categorisation, the next major aspect to understand for analogue audio cables is Balanced vs Unbalanced cables.

Balance vs Unbalanced Audio Cables

While certain types of audio cables are regarded as balanced, others as unbalanced. This is a crucial concept that needs to be clarified before we dig into the various types of audio cables available and what they do.

Why is it important, you ask? The reason is noise.

Noise is any unwanted signal that interferes with the wanted signal. Mostly noise comes from other electronic signals interfering with the desired signal.

For example, if you run a cable from an electric guitar to an amplifier, the cable should only transmit the output signal from the guitar to the amplifier.

But if you put any transformer near the cable carrying the signal, it will interfere with the guitar signal and produce noise. The interference happens due to magnetic fields produced by different electronic signals.

So to reduce the impact of interference, balanced cables are used.

Unbalanced Audio Cables

In an unbalanced audio cable two conductors are used, a signal and a ground,  to carry an unbalanced audio signal. The audio signal is transported by the signal wire, as its name suggests, to its destination. The signal uses the ground wire as a point of reference.

Unbalanced cables will only have a single conductor wire and a ground, while balanced cables have two conductor wires and a ground.

• Unbalanced cables are prone to interference.
• Unbalanced cables become more prone to electrical interference as the cable length increases.
• RCA cables and TS Cables(Guitar Cables) are unbalanced cables.

Balanced Audio Cables

A balanced audio cable has three conductors - a ground and two more carrying copies of the same incoming audio signal reversed in polarity, sometimes referred to as a hot (positive) and cold (negative) signal. 

A balanced audio cable is specifically designed to eliminate electrical interference (hum or buzz) from any other electrical cable or source.

The two conductor wires (hot and cold) are specifically designed to work in reverse polarity. This cancels out any outside electrical noise that might interfere with or impact the signal.

How noise is cancelled in balanced cables?

The good thing with the balanced cable is that if noise is picked up along the route, it will be added to both cables.

The polarity of the cold signal is reversed at the end of the line, putting the hot and cold signals back into phase and synchronisation while eliminating any unwanted interference. Therefore, the noise carried by the cold signal cancels out with the noise in the hot signal when the polarity of the cold signal flips to match the polarity of the hot signal at the terminating end. 

The noise serves as the common signal between the two, and the act of cancelling it out is known as common-mode rejection, leaving just the original signal minus the noise. 

This makes balanced cables ideal for use when you require long cable lengths.

• Balanced cables are less prone to interference.
• Balanced Cables can be used for longer lengths.
• XLR cable(Microphone) and TRS Cables are balanced cables.

So why use unbalanced cables?

If you have an unbalanced system, using a balanced cable will be just a waste of money and resources. To have a completely balanced system, your equipment should have a balanced I/O as well and your cables should be balanced. So using a balanced cable with an unbalanced signal will not make any difference. Unbalanced cables and balanced audio cables deliver the same audio quality if they are not exposed to interference.

It's important to keep in mind that to have a truly balanced system, your circuit's points must all be balanced. This includes:

• Output on your gear.
• Cables
• Input it’s going into (like your mixer, PA, turntable etc.)

All of your cables, as well as your equipment, must be balanced if you want to have a genuinely balanced audio system. Your connection will become unbalanced if any one of the above is unbalanced.

If you have an unbalanced system, try keeping all of your cable lengths as short as possible, ideally under six feet, to prevent excessive signal interference. 

How to know if your gear is balanced or unbalanced?

Your equipment is balanced if:

1. It features balanced inputs or outputs like XLR, and TRS.
2. It is stated in the handbook or manual.

Your gear is unbalanced if:

1. It's a bass or a guitar.
2. It features mono or stereo TS outputs.
3. RCA inputs or outputs are present.

If you're unsure, always check the instructions/manual or do some research.

If you are getting confused with the terms RCA, TRS, TS and XLR, don't worry. These are commonly used types of audio connectors used in audio cables. 

In the next article understand the various audio connectors and cable types that a home studio environment needs. Everything will be covered, including which cable you need to connect various instruments and devices like a guitar, synth, studio monitors, microphone, etc.