What Speaker Cables do PA Speakers use?
Speaker Cables
When setting up a PA (Public Address) system using passive speakers and an amplifier, the type of speaker cables you use is crucial to the overall performance and sound quality. These cables play a pivotal role in delivering crisp and clear audio from your PA speakers.
In this guide, we will take a look at the most common types of speaker cables and connectors used for passive PA speaker systems, Understanding the pros and cons of each type can help you make an informed decision and ensure your sound system is operating at its best.
Bare Speaker Wire
Bare speaker wire or speaker cable is one of the most fundamental types of wiring used in audio systems. It consists of two conductor cores which are made from multiple strands of copper, with plastic sheathing to separate the cores from each other. Having no plugs means bare speaker wire can be easily customised to the desired length without any special tools.
This type of two-conductor wire is typically colour-coded (red and black) to denote positive and negative connections, making it straightforward to connect the speakers and amplifier correctly which use those colours on their terminals, though even plain coloured cable will have some form of core identifier, from a dotted to line to a moulded ridge to one core.
However, bare speaker wire has its drawbacks. It can be damaged fairly easily, especially in its budget ‘figure of 8’ format which doesn't have any extra protection over the standard thin plastic sheathing. The lack of fitted plugs also means that the exposed copper ends often become frayed and damaged, especially with repeated connections over time.
While it offers flexibility and ease of use, bare wire connections are not ideal in a professional setting and should always be the last choice if more secure output terminals are present on the speaker and amplifier.
Jack Speaker Cable
Jack speaker cables, also known as 1/4 inch (6.35mm) jack cables, are another common type of connection used in PA systems. These cables are recognised for their sturdy connectors and ease of use. The jack connector is identical to those used for the audio signal of electric guitars and other musical instruments, though the cable itself is not the same.
The primary advantage of jack speaker cable is their durability and robust construction. They are less prone to accidental disconnections compared to bare wire, and their solid connectors provide a reliable link between your amplifier and speakers. Moreover, the plug-and-play nature of jack cables makes setup and teardown quick and efficient, which is ideal for live performances where time is of the essence.
On the downside, jack plugs and sockets can wear out over time with repeated plugging and unplugging (depending on their quality). Additionally, they are generally less flexible than bare wire options because the cable is double insulated, which means the two cores are individually sheathed but are also inside a thicker rubberised covering.
It’s important to know that a speaker cable with jack plugs is a 2-core cable, whereas an instrument lead is a single core with a braided metal shield. They can be easy to confuse as they look almost identical, but they are not interchangeable, and an instrument lead is actually a fire risk if used for a speaker-to-amp connection as the shield is not intended to handle any current.
Speakon Speaker Cable
The big one. Speakon speaker cables are considered the gold standard in professional audio settings. Developed by Neutrik, these cables feature a unique twist-lock connector that ensures a secure and stable connection. This heavy-duty design prevents accidental disconnections, making them highly reliable for high-stakes situations like concerts and large events.
One of the key benefits of Speakon cables is their ability to handle high power levels, which is essential for large PA systems. Available as 2-pole (NL2) or 4-pole (NL4), these connectors are designed to carry high currents without heating up, and their physical size allows for much larger cable gauges to be used ensuring consistent performance during long sessions at high volumes.
Additionally, the robust construction of Speakon connectors protects them from the wear and tear that can affect other types of connectors over time. They are easy to work with thanks to their locking mechanism, which provides a tactile confirmation that the connection is secure. They are the preferred choice for professional PA systems and high-power applications such as line-arrays.
Disadvantages are that Speakon cables tend to be more expensive than other types of speaker cables, and they are fairly bulky to handle and store. They also require compatible equipment, which might necessitate additional investment or mismatched plug types on cables if your current speakers or amplifier doesn't support them.
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Delving Deeper: Speaker Cables
Understanding the different types of speaker cables used in PA systems is just the beginning. To optimise your audio setup, it’s essential to dive deeper into various aspects of speaker cables, including wire gauge, length, and potential pitfalls. Let's answer some of the most popular questions:
What Gauge Wire for Passive Speakers?
Electrical cable capability is measured in two ways and you will often see both in a cables specifications:
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AWG - (American Wire Gauge)
The gauge of the wire refers to its overall thickness, with lower numbers indicating thicker wires. For passive speakers, a common recommendation is to use a 16-gauge wire for most applications. However, if you are running cables over longer distances or using high-powered speakers, a thicker 14-gauge or even 12-gauge wire might be necessary to ensure minimal signal loss and maintain sound quality.
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mm² (millimetre squared)
The metric version. There are conversion charts online but most cable will have both AWG and metric sizing. The measurement is the cross-section of the individual copper conductors, and for speaker cable will be a double figure, such as 2x 0.75mm²
Copper cable has limitations for voltage and current, so as the speakers and amplifier specifications get larger, so must the cable. The same is true for length, as the longer a cable is the more resistance it builds up, which increases the current pull and will make the cable heat up. Going up to the next gauge simply means more copper, which offers higher current capacity and less resistance, reducing the strain on the cable and the amplifier.
Though there are lots of sizes and variations, you will find the most common sizes for Hi-Fi speakers or PA speakers are the following:
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0.75mm² (18 AWG)
Standard-size twin speaker cable for low-power applications. Supplied free with many home stereos. Fine for ceiling speakers, bookshelf speakers and surround speakers.
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1.5mm² (16 AWG)
A great option for both Hi-Fi and small to medium PA speakers and subwoofers up to around 200W, or for longer runs to medium-size speakers. Most standard Speakon leads will use a 2x 1.5mm² cored cable.
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2.5mm² (14 AWG)
Good for longer runs, PA subwoofers (short run only) and medium to large PA speakers. This heavier-duty cable gives you better current handling over longer cables. Pro series Speakon cables will be 2x 2.5mm².
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4.0mm² (12 AWG)
A thicker cable that is mostly used for higher power passive PA subwoofer connection, though audiophiles also use it for high-end Hi-Fi speaker wiring, preferring the larger copper content and low resistance it provides.
Speaker cable sizing is something that needs to be calculated to suit the equipment and the distances being used. Most finished cables with plugs will be either 2x 1.5mm² or 2x 2.5mm² which are suitable for most PA speakers up to 15 inches and up to around 20m.
For higher power usage such as 18-inch subwoofers or line array speakers, the cables will often be 2x 2.5mm² or 2x 4.0mm² to ensure optimum performance when passing the higher current that comes with these higher excursion speakers.
Distance and the impedance rating of the speakers and amplifier must be taken into account when calculating speaker cable, especially for longer cable runs on stages or for installations.
Can I use Microphone Cable for Passive Speakers?
Microphone cables are not suitable for use with passive speakers. They are typically designed to carry low-level audio signals rather than the higher power signals required by speakers. The same is true of instrument cables, which are designed to carry low-voltage audio signals at virtually no current.
Using either of these as speaker cable would result in extremely poor performance, potential damage to your equipment, and the risk of melted cables or fire. It's crucial to use cables specifically designed for the current requirements of speaker-level signals.
How long can Passive Speaker Cables be?
The length of your speaker cables can significantly impact the performance of your PA system. Generally, shorter cables are better because they minimise signal loss. However, in practical applications, cables often need to be longer to accommodate the layout of a venue.
As a rule of thumb, for runs up to about 50 feet, a 16-gauge wire is usually sufficient. For lengths between 50 and 100 feet, a 14-gauge wire is recommended. Beyond 100 feet, a 12-gauge wire is advisable to maintain sound quality.
As previously stated though, this also changes depending on the impedance, so must be calculated specifically to suit each situation. As an example of this, taking a standard 2x 1.5mm² (16 AWG) cable, with an 8 Ohm load you could go up to 50ft, but drop that load to 4 Ohm and you halve that distance to 24ft because the lower loading means the current is higher.
As a general rule, go with the best, most heavy-duty cables you can do if they are pre-configured such as Speakon or Jack plugs and you will be fine, as these are manufactured especially for professional use.
Does thicker Speaker Wire sound better?
Thicker speaker wire can indeed sound better, particularly over long distances. This is because thicker wire has lower electrical resistance, which reduces signal loss and ensures that more of the amplifier’s power reaches the speakers. While the difference might not be noticeable over short distances, it becomes more significant as the cable length increases.
Hi-Fi enthusiasts will often use 4.0mm² cable even though at the volume levels and distances involved their equipment could use 1.5mm² or even less. They prefer the efficiency and clarity that the heavier copper content brings to the system, allowing the amplifier and speakers to do their job as unimpeded as possible.
Do shorter Speaker Cables sound better?
Similarly to the thickness of the cable, shorter speaker cables typically sound better because they again offer less resistance and lower the chance of signal degradation. The shorter the distance the signal has to travel, the less it will be affected by factors such as resistance, heat build-up, and interference from outside sources, resulting in clearer and more accurate sound reproduction.
Technically it's also worth noting that because of resistance and impedance, speaker cables should ideally be kept the same length. It's not so noticeable in a mono setup, but hugely mismatched cable runs can introduce timing delay issues to stereo and especially surround sound systems.
Keep speaker cables as short as possible, and ideally of equal lengths.
What happens if Speaker Wire is too thin?
Using speaker wire that is too thin can lead to several issues. Less copper content in cable means higher resistance, which can cause significant signal loss and reduce the efficiency of your PA system.
Thin wire has the audible effect of killing off bass response and adding a harshness to the treble as the volume gets turned up, and the effect worsens with longer cable, reducing power as the load increases. This in turn places an immense strain on the amplifier output transformer causing it to get hot, and the resulting signal distortion will damage the speaker's voice coil. It's a knock-on effect that only ends badly.
More importantly, certainly from a safety aspect of things, if the speaker cable is too thin and is used at a higher volume, the resistance and current draw fighting each other will have the effect of making the cable get hot. This will eventually lead to either damage to the amplifier, or in extreme cases, the cable will melt its plastic covering.
It's essential to match the wire gauge to the power requirements and distance to ensure optimal performance.
Is there a wrong way to wire Speakers?
Yes, there is indeed a wrong way to wire speakers. One of the most common mistakes is reversing the polarity – connecting the positive terminal of the amplifier to the negative terminal of the speaker, and vice versa. This will cause phase issues, where the speakers push and pull out of sync, leading to a muddled and less impactful sound. Always ensure that the positive and negative terminals are correctly matched.
Depending on the type of amplifier being used you can also wire to the wrong outputs which can damage both the amplifier and speakers. The most common amps for this to occur are commercial units which often include low impedance outputs and 100V line high impedance options. These are very different outputs, and either can cause significant damage to a speaker not designed for that signal type.
Always ensure that you understand the equipment you are using, and what the symbols and terminology mean, and always double-check your connections before powering up in case a mistake has been made.
Summary
Choosing the right speaker cables for your PA system is crucial for achieving the best sound quality and reliability. Bare speaker wire offers flexibility and ease of use but ideally should be a last resort when it comes to PA speakers due to its more fragile construction.
When selecting speaker cables, consider the wire gauge based on the power requirements and distance of your setup. Be mindful of the cable length to minimise signal loss. Thicker and shorter cables generally offer better performance, ensuring that your PA system delivers clear and powerful sound.
By understanding these key aspects of speaker cables and connectors, you can make informed decisions and optimise your PA system for any venue or event, ensuring a good quality sound and the longevity of your equipment.