Unbalanced vs. Balanced Audio – What’s the Difference?

Go into any music store and check out the cable section. You will come across a dizzying selection of instrument cables, speaker cables, microphone cables, midi cables, splitter cables, patch cables – so many cables that you will leave the store more tangled than anyone else.

While it can be overwhelming, analog audio cables can be divided into two main categories: those that carry unbalanced audio and those that carry balanced audio. Let’s dive into the details of these two, examine the difference between balanced and unbalanced audio, and see some examples of both.

Unbalanced cables

An unbalanced cable consists of two separate wires: the signal wire and the ground wire. As the names suggest, the signal wire carries the audio signal from the source to the destination, while the ground wire provides a ground connection for the circuit to reduce noise.

As shown in the figure below, the signal wire is coated with insulating plastic, around which the ground wire is braided. In this way, the ground wire acts as a type of electromagnetic shield that intercepts any radio frequency (RF) interference that reaches the signal wire.

Although unbalanced cables are two-wire, they are limited to carrying a single mono signal – for this reason they are often used for mono sources such as guitars or keyboards.

TS cable

TS (Tip Sleeve) cables use a ¼-inch connector with two contacts – a tip and a sleeve. These are separated by an insulating ring around the body of the connector. These cables are standardized so that the tip is the Signal passes while the sleeve is connected to the ground wire.

TS cables generally come in two varieties: instrument and loudspeaker. Although they both end in 1/4 ” TS connectors, they use very different internal wiring and it is important not to get them mixed up.

Speaker cables vs. instrument cables

Loudspeaker cables are used to connect power amplifiers to passive loudspeaker boxes – as such, they must be able to carry the enormous amounts of electricity required to power these loudspeaker arrays. Such a high current requires wires thick enough so that you don’t run the risk of setting the whole studio on fire!

If you connect a standard instrument cable from an amplifier to a speaker box, you risk not only damage to the amplifier but also possible fire. This is because the thin wire of an instrument cable cannot adequately dissipate the heat generated by such a high current and can burst into flames!

On the other hand, a speaker cord used in place of an instrument cord can introduce unwanted noise – unlike a standard TS instrument cord, a speaker cord is not shielded at all. Because these cables do not use a ground / shield wire, they are very susceptible to RF interference.

When connecting an amplifier to a speaker box, this doesn’t matter as the output of the amplifier is much larger than any possible noise, while the comparatively poor output of a guitar pickup can easily be overwhelmed by RF interference.

Cinch cable

Another unbalanced cable you may come across is the RCA cable. Named for the Radio Corporation of America, RCA cables are often found on the back of televisions, stereos, and older recording devices. Internally, cinch cables are identical to TS cables, they just use different plugs.

With the advent of HDMI and Bluetooth, RCA cables are largely being phased out in the consumer audio world, but they are still used in recording studios. When it comes to a great sounding vintage device, few engineers would let a slightly outdated connector get in the way.

Balanced cables

Every cable, regardless of the shield, picks up a little noise while traveling. With sources like guitars and instruments with relatively high power and short cable runs, this noise is not a major problem. For microphones, however, this is a big deal.

The output of a microphone pales in comparison to that of an electric guitar, so using unbalanced cables is generally out of the question. So how do we isolate the audio we want and how do we get rid of that noise?

This is where the balanced cable comes in – essentially, these are just two unbalanced cables that share a ground wire. With a little phase inversion physics, we can’t just remove the noise from the resulting one Signal remove, but also amplify the clean audio by a factor of two!

The balancing act

Imagine you have two wires that both carry audio from point A to point B. When the audio enters the wires at point A, a component on the second cable will rotate the audio 180 degrees. To simplify matters, think of this as a negative version of the audio on the first cable – the two will cancel each other out:

On the journey from A to B, both positive and negative audio pick up the same sound – let’s think of the sound as positive for our sake:

Once the audio / noise mix reaches point B, another component flips the second wire 180 degrees back into phase. This makes the negative audio on wire two positive and at the same time the positive noise on wire two negative:

As a result, the strength of our audio doubles while our noise is completely faded out! This is the theory behind balanced cables; It is this balancing of the audio that allows us to cleanly amplify low output signals without worrying about the noise overwhelming the audio.

XLR and TRS cables

Common balanced cables that you can buy are XLR (microphone) or TRS (tip, ring, sleeve) cables:

XLR and TRS cables are internally identical despite the different connections. However, most microphones and mic preamps are standardized for XLR connection, which is why most stores refer to XLR cables as “microphone cables”. TRS cables, on the other hand, are generally only used to connect pro audio equipment.

Winding up the cables

Generally, unbalanced cables are used for instrument or speaker connections, while balanced cables are used for microphones and professional audio equipment.

Choosing the right analog audio cables can be confusing – knowing balanced versus unbalanced cables will help you choose the right cable. Analog audio isn’t the only place where cabling skills can come in handy – check out some of our other articles for more information on cables used with other types of media!

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