Unbalanced vs. Balanced Audio Whats the Difference?
Walk into any music store and look at the cable section. You’ll be met with a dizzying array of instrument cables, speaker cables, microphone cables, midi cables, splitter cables, patch cables – so many cables that you leave the shop more tangled up than any of them.
While it can be overwhelming, analog audio cables can be broken down into two main categories: those that pass unbalanced audio, and those that pass balanced audio. Let's dive into the minutiae of these two, exploring the difference between balanced and unbalanced audio, and checking out a few examples of both.
Unbalanced Cables
An unbalanced cable is made up of two separate wires: the signal wire and the ground wire. As the names imply, the signal wire carries the audio signal from source to destination, while the ground wire provides a grounding connection for the circuit to help alleviate noise.
As shown in the diagram below, the signal wire is sheathed in insulating plastic, around which the ground wire is weaved. In this way, the ground wire acts as something of an electromagnetic shield, working to intercept any Radio Frequency (RF) interference from reaching the signal wire.
Despite being comprised of two wires, unbalanced cables are limited to carrying a single mono signal – for this reason, these are often used for mono sources like guitars or keyboards.
TS Cables
TS (Tip Sleeve) cables use a ¼” connector, with two contacts – tip and sleeve. These are separated by an insulating ring around the body of the connector. These cables are standardized such that the Tip passes the signal, while the Sleeve connects to the ground wire.
TS cables generally come in two flavors: Instrument and Speaker. While both terminate in ¼” TS connectors, they utilize very different internal wiring and are important not to mix up.
Speaker Cables vs. Instrument Cables
Speaker cables are used for connecting power amplifiers to passive speaker cabinets—as such, they must be able to carry the huge amounts of current required to power these speaker arrays. Such high current requires adequately thick wires, lest you run the risk of setting the whole studio on fire!
If you were to connect a standard instrument cable from an amplifier to a speaker cabinet, you risk not only damaging the amplifier but potentially starting a fire. This is because the thin wire of an instrument cable cannot adequately dissipate the heat created by such a high current and can burst into flames!
On the flip side, a speaker cable used in place of an instrument cable can result in unwanted noise—unlike a standard TS instrument cable, a speaker cable is not shielded at all. Since these cables do not utilize a ground/shield wire, they are highly susceptible to RF interference.
When used to connect an amp to a speaker cabinet this is a non-factor, as the output from the amp is much greater than any potential noise, whereas the comparatively paltry output of a guitar pickup can be easily overwhelmed by RF interference.
RCA Cables
Another unbalanced cable you may come across is the RCA cable. Named after the Radio Corporation of America, RCA cables can often be found on the backs of televisions, stereos, and older recording equipment. Internally, RCA cables are identical to TS cables, they just use different connectors.
With the advent of HDMI and Bluetooth, RCA cables are largely being phased out in the consumer audio world, but there are still uses for them in recording studios. When it comes to a great-sounding piece of vintage gear, few engineers would let a slightly out-of-date connector stand in their way.
Balanced Cables
Any cable, regardless of shielding, is going to pick up a little bit of noise along the way. For sources like guitars and instruments, with relatively high output and short cable runs, this noise is not a huge issue. 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 that we want, and get rid of this noise?
Here’s where the balanced cable comes in—essentially, this is just two unbalanced cables that share a ground wire. With a little bit of phase flipping physics, we can not only remove the noise from the resulting signal but also amplify the clean audio by a factor of two!
The Balancing Act
Imagine you have two wires, both carrying audio from point A to point B. When the audio enters the wires at point A, a component on the second wire flips the audio 180 degrees. In an oversimplification, think of this as a negative version of the first wire’s audio—the two will cancel out:
While traveling from A to B, the positive and negative audio both pick up the same noise—for our sake, let’s think of the noise as positive:
Once the audio/noise concoction hits point B, another component flips the second wire 180 degrees, back into phase. This turns the negative audio on wire two positive, and simultaneously turns the positive noise on wire two negative:
As a result, our audio doubles in strength, while our noise cancels out entirely! 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 & TRS Cables
Common balanced cables you can purchase would be XLR (Microphone) cables or TRS (Tip, Ring, Sleeve) cables:
CloseXLR and TRS cables are identical internally, despite the different connectors. That said, most microphones and microphone preamps are standardized for XLR connection, which is why most shops will label XLR cables as “Microphone Cables.” TRS cables, on the other hand, are generally only used for connecting pro audio equipment.
Wrapping Up the Cables
Generally speaking, unbalanced cables are used for instruments or speaker connections, while balanced cables are used for microphones and pro audio equipment.
Picking the right analog audio cables can be confusing—the knowledge of balanced vs. unbalanced cables will go a long way to help you choose the right cable for you. Analog audio isn't the only spot where knowledge of cabling can come in handy - check out some of our other articles for more info on cables used for other types of media!
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