Are Balanced Audio Cables Better?

Contents:

Intro
Common-Mode Rejection
Cable & Connector Types
Cable Placement
The Right Cable for the Right System

Cables matter. They’re an important part of the equation if you are trying to make your system as clean sounding as possible. Not all cables are created equal and are oftentimes an oversight in improving the sound quality and clarity of your system. The cables are what is actually carrying the sound from your source to your output, so the materials used and the quality of the cable itself has a dramatic impact on what you are going to hear. Things like noise isolation, cable length, and input gain/level are all very important things to consider when trying to determine what cable solution is best for you and your system.

Cables come in two varieties: balanced and single ended. On their own, one is not necessarily better than the other. What matters is the application for which they are used, and which cable will be most effective in carrying out the best signal to your components. The common myth is that balanced cables are better than single-ended. Why is that? Well, probably the top reason people think balanced cables are better is that they are more resistant to noise and interference. The last thing you want to hear when trying to listen to your music is static, hiss, or other noise artifacts in your system diminishing the quality and clarity of your music.

Let's take a look at how balanced cables are able to keep out the noise in their signal.

Most people think about 'balanced' as Common-Mode Rejection, where you're using long runs of balanced cables between two pieces of equipment. In each cable, you have two signal wires: a plus and a minus, and the ground line. Both the send and receive lines carry a copy of the signal, but with the polarities reversed. The receivers look at both ends, average out the signal-to-noise ratio and get rid of the noise by flipping the polarity. This is called Common-Mode Rejection due to the noise being the 'common' signal between the send and receive lines. All balanced cables utilize common-mode rejection.

However, common-mode rejection is not really "balanced”; it more so describes the function of how the dual lines work to cancel out external noises in that signal. Oftentimes common-mode rejection is referred to when talking about balanced cables rather than balanced circuitry. Therefore, most people have the impression that a balanced connection is superior because it is more resistant to external signal noise sources. While this is true, it does not necessarily mean that the balanced line is "better" than a single-ended cable.

Noise or common-mode voltages can come from numerous sources, so the differential amplifier (See “The Differential Amplifier”) must be efficient and effective at eliminating the noise.

"Common-mode rejection is not really "balanced”; it more so describes the function of how the dual lines work to cancel out external noises in that signal."

Unbalanced or single-ended cables, on the other hand, do not have dual polarity lines. The ground wire in unbalanced lines serves two functions: it carries part of the audio signal and also shields the main signal wire (partially) from outside noise interference. Because of the internals of single-ended cable design, however, the line can also act as an antenna in picking up external noise sources. This is why limiting single-ended cables to shorter lengths is greatly preferred over longer lengths. The longer the cable - the more noise it can pick up.

Short length single-ended cables are good for noisy signal environments and for low-level signals from instruments (keyboards, guitars, etc). Because of their native low-level signal, any noise interference is not amplified by more active sources or higher-level/gain signals.

Cable & Connector Types

You can generally tell if you have a balanced or single-ended cable based on the connector at the end of the cable.

Balanced cables typically have either XLR connectors or TRRS connectors. XLR cables have a 3 or 4-pin tip while TRS cables have a quarter-inch connector with two rings dividing the "tip," the "ring," (x2) and the "sleeve" (T-R-R-S). Unbalanced cables have TS (like TRS but without the ring – also referred to as instrument cables), RCA or SpeakON connectors. There are also other balanced cable types that have 4 or 5 pin configurations. Typically, these XLR connector types are solely used for a balanced headphone, microphone input, or balanced speaker output.

Also, keep in mind that balanced cables also tend to be more expensive than single-ended options. Some of that has to do with the popularity of balanced cables being a popular option for long cable runs due to their noise resistance.

Headphone Cables

Interconnect cables typically connect a component device to another component device. Headphone cables are directly connected to the headphones themselves (or through detachable methods).

As we'll learn more on the next page, headphones are not balanced or single-ended because they are just speakers, unable to do common-mode rejection. They can only receive signal and output analog sound. The cable that is connected to the headphone, on the other hand, can be balanced or single-ended. Headphone manufacturers have various connector types to their equipment, but the end-point to your amp or DAC will always be either an XLR or TS/TRS connector.

Sometimes we have to perform surgery on a set of headphones if they want a specific connector or cable type. Most manufacturers design their headphones with detachable cables now to help with portability and storage, but here at Moon Audio, we can help create custom and modular cable systems for whatever your needs may be. Here are some examples of balanced and unbalanced cable solutions we provide:

As you can see, there are many different cable types and connectors to choose from. Do your headphones have an attached cable with a connector that is not compatible with your gear? No problem. Again, headphones are just speakers and you can wire any kind of cable and connector to them. Balanced cables, unbalanced cables, XLR, TRS, TRRS connectors, etc; what really matters is the gear you are connecting them to. We'll learn more about that on the next page. Let’s get into cable placements and cable lengths next.

Cable Placement

Depending on the placement of the cables, you can also minimize the amount of interference intercepting the signal. For instance, if you have single-ended cables, running them perpendicular along power lines (as opposed to running them parallel) will minimize the amount of noise that will enter the signal. Because the cable only has a single polarity it is unable to do common mode rejection and is thus more susceptible to noise and interference.

Noise interference is not a concern with balanced cables on the other hand since they can do common-mode rejection.

So, in applications where you are running lines near power sources or over longer distances, balanced cabling would be preferred over single-ended. In scenarios where you do not need long cable solutions and proximity of power lines are not a concern, single-ended cables should be just fine.

If your sole factor in determining the cable you need is based on noise and interference concerns, then in some cases you can save money and opt for more budget-friendly single-ended cables. If you are very detailed about the placement of your wires and make sure there is no power current crossover, you have shorter cable lengths, etc, then you could potentially get away with single-ended solutions. But you'll have to assess this on a case-by-case basis. Environmental factors, RF, various wireless signals, power cable placement, and much more need to be factored in to make the best decision on the proper cable type and requirements for your situation.

The Right Cable for the Right System

Cables have the power to make your signal extremely clear or extremely poor. They are an integral component to your system that often gets overlooked or treated as an afterthought. Keep in mind that balanced cables are not necessarily better than single ended cables. It depends on what you plan on using them for: longer cable runs versus shorter runs, need for noise resistance, signal chain, components and inputs/outputs, etc.

If your signal/source is unbalanced, then using a balanced cable is not going to add any sonic benefit or enhance your sound. The connectors at the ends of your cable must also be appropriate for the cable type. For instance, if you attach TRS connectors to a single-ended cable, it does not magically make it a balanced cable.

On the other hand, if you connect a single-ended cable to a balanced source, it will still "work" and transfer the audio signal, but it will also still be susceptible to noise interference since it will not be able to utilize common-mode rejection (and is ultimately not advised).

Application is key. If you use the wrong cable for the wrong application, it can actually be detrimental to your sound. Knowing how to use your gear appropriately and for the right purpose can make all the difference.