The Beginner's Guide to Audio Cables
In this guide, I'll be going over everything you need to know about common audio cables that you'll find in a music studio. The main focus of this article is on the practical use of different cables, and when it's appropriate to use them. I'm not going to be diving too heavily into the physics behind how these cables work, but I'll be providing external links throughout the article if you're interested in learning more about anything in particular.
I'll be covering the following topics in this guide:
- Analog vs. Digital Cables
- Types of Analog Cables
- Levels of Analog Audio Signal
- Common Analog Connectors
- Common Digital Cables
- Power Cables
- Cable Management Tools
- How to Properly Wrap Cables
- Tips for Buying Audio Cables
1. Analog vs. Digital Cables
There are two types of cables that you'll find in a studio that are used to transmit information; analog and digital cables.
Analog cables use continuous waveforms to transmit information. For example, if the information is a 100Hz sine wave, the voltage running through the analog cable will perform 100 positive-negative cycles per second.
There are two types of analog cables; they include unbalanced and balanced cables. Analog cables can transmit line, instrument, or mic level signals.
Digital cables use binary code (1s and 0s delivered as a series of transitions in voltage) to transmit information. There are numerous different types of digital cables, and old forms are digital cables are continually being replaced by newer ones as technology advances.
2. Types of Analog Cables
The two main types of analog cables are unbalanced cables, and balanced cables.
Unbalanced cables contain two wires; a ground wire, and positive polarity (“hot”) wire. The main issue with unbalanced cables is that they pick up noise; especially with cable lengths of over 20 feet. Unfortunately, due to the way many instruments are designed, they can only produce an unbalanced signal.
Balanced cables contain three wires; a ground wire, positive polarity (“hot”) wire, and negative polarity (“cold”) wire. Balanced cables use phase cancelation to remove noise. The same signal runs through both the positive polarity and negative polarity wires; the only difference being that the polarity of the negative polarity wire is inverted. Both wires pickup noise as the signal travels from one end of the cable to the other, but when they combine at the end of the cable, the negative wire’s polarity is reversed. The noise patterns of the two wires are now in opposite phase with one another; resulting in silence.
You can use a DI box (also known as a direct box or direct injection box) to convert an unbalanced signal to a balanced signal; this will allow you to run signal through significantly longer cables without having to worry about noise.
3. Analog Audio Signal Levels
There are four levels of analog signal that you need to know about; they include mic level, instrument level, line level, and speaker level signal. They primarily differ based on their voltage level, increasing in strength in this order: Mic > Instrument > Line > Speaker.
Mic Level Signal
Mic level signals are produced by microphones; they need to be brought up to line level using a microphone preamp. I just reviewed the Clarett 4Pre USB by Focusrite for SonicScoop and the quality of the mic pres in the unit is incredible. If you're looking to upgrade your audio interface and gain access some extremely clean mic pres, you can pick up the Clarett 4Pre USB here.
Instrument Level Signal
Instrumental level signals are produced by guitars and basses; they need to be converted into mic level signal using a DI box and then brought up to line level. In some situations, you may not need to convert a signal to mic level, such as when running an instrument signal into an amp, or the high-impedance (HI-Z) input on an audio interface.
Line Level Signal
Line level signal is the standard for all studio equipment. Your goal should often be to bring a signal up to line level as soon as possible. Once it’s at line level, you’re free to run it through signal processing equipment such as compressors, EQs, saturators, etc.
Speaker Level Signal
Speaker level signal is signal that has been amplified using an amplifier. When you run a line level signal into your studio monitors, the amplifiers built into your speakers boost the signal up to speaker level. Smaller speakers require less volts to produce sound waves, whereas large speakers require more volts.
4. Common Analog Connectors
Before getting too ahead of myself, I want to point out that you’ll mostly hear people refer to audio cables (as a whole) by their connection type, as opposed to the cable being used to transmit information between the two connectors on the ends. For example, if you have a coaxial cable that uses RCA connectors, most people would just call the cable and connectors as a whole an RCA cable; even though it’s technically inaccurate.
I’ll be talking about connector types in this section because you’re going to find many analog cables that have different connector types on each end; in situations like this, people will say, “I need an XLR male to XLR female cable,” and actually refer to the connection types used.
It's pretty easy to tell a male connector from a female connector because the male variant typically looks like a robot dick, and the female variant usually looks like what you'd plug the robot dick into; good luck forgetting this now.
An RCA (phono) connector is capable of carrying audio and video signals. RCA connectors are capable of transferring both analog, and digital audio signals. When used with analog cables, RCA connectors allow you to transfer unbalanced mono signal, so two RCA cables are required if you wish to transfer stereo information. When used with digital cables, RCA connectors allow you to transfer stereo, and surround sound information.
RCA connectors have a central male connector that looks like a pin, surrounded by a ring; this connector is inserted into a female jack that has a hole and a ring surrounding the hole. It’s essential that the ring of the male connector is inserted far enough into the female jack that their rings touch. A good connection between the rings will ensure grounding, which prevents loud “buzz” from occurring.
The cables you used to use to connect your DVD player to your TV were 3 male to 3 male RCA cables; they sent stereo audio, as well as video signal to your television.
An XLR connector is a standard connector type for balanced audio cables. XLR connectors can come with as many as 10 pins, but 3 pin XLR connectors are the most common. XLR connectors allow you to transmit balanced mono signal, so two XLR cables are required if you wish to transmit a stereo analog signal.
Due to the way that the male ground pin contacts the female connector before the other pins, it's possible to connect and disconnect XLR connections in live sound equipment without picking up external signals.
The cable you use to connect your microphone to your microphone preamp is usually a female XLR to male XLR cable.
The main difference between TS (tip-sleeve) and TRS (tip-ring-sleeve) connectors is that TS connectors are generally used for unbalanced mono signals, while TRS connectors are generally used for balanced mono signals, or unbalanced stereo signals. TRS connectors have a metal ring around the base of the head of the connector, while TS connectors do not; this third contact point is what allows TRS connectors to transmit balanced mono signals, or stereo signals.
The cable you use to connect the line outputs from your audio interface to your monitors is usually a TRS male to TRS male cable (mono, balanced).
The cable you use to connect the headphone monitoring output on your audio interface to your headphones is usually a 1/4" TRS male to 1/8" TRS male cable (stereo, unbalanced).
TT (Tiny Telephone) connectors are mid-size TS or TRS connectors with a smaller shaft and slightly different shape; in the United Kingdom, these are sometimes referred to as “bantam” connectors. TT connectors are commonly used for patch bays because their small size takes up less space than TS and TRS connectors. Additionally, the shape of TT connectors makes them less likely to cause shorting when they’re plugged in.
5. Common Digital Cables
There are a number of digital cables that you're likely already familiar with because they're used to connect devices to your laptop. However, there are also some less familiar cables that you'll need to connect to your audio interface in order to use.
USB (Universal Serial Bus) is an industry standard that was created to standardize the connection of peripheral devices such as keyboards, audio interfaces, external hard drives, etc.; USB allows these devices to communicate, and to provide each other with electric power.
A serial bus transfers one bit of information at a time, while a parallel bus incorporates multiple physical connections to transfer more data in a shorter amount of time. USB cables (which are serial buses) are generally thinner, lighter, and less expensive than parallel bus cables; this makes them ideal for consumer products.
USB has used many different connector types over the years including Type A, Type B, Mini A, Mini B, Mini AB, Micro A, Micro B, Micro AB, and Type C. You can view a chart of all the connector types here.
USB cables have gone through multiple generations with varying data transfer speeds, and USB 3.1 is the most current generation as of August in 2018:
Firewire cables are high-speed serial buses that are quite comparable to USB cables; they’re capable of transferring data, as well as electric power to peripheral devices. FireWire is actually Apple’s name for the interface standard called IEEE 1394. Most Macs had FireWire ports from the years 2000-2011.
A lot of people preferred using FireWire over USB 2.0 due to it’s faster data transfer rate. However, with the creation of USB 3.0+ and Thunderbolt, FireWire is becoming increasingly less common due to its inferior data transfer rates.
FireWire cables have gone through multiple generations with varying data transfer speeds, and FireWire 800 is the most current generation as of August in 2018:
Thunderbolt is a hardware interface standard developed by Intel and Apple that allows the connection of peripherals to a computer. Thunderbolt 3 cables are capable of transferring data faster than both USB 3.1 and FireWire 800 cables.
Thunderbolt 3 cables use a USB Type C connector that's the exact same as the connector found on USB 3.1 cables; the difference is that Thunderbolt 3 cables transfer data faster. Thunderbolt 3 cables will typically have a thunderbolt symbol on the USB Type C connector that allows you to distinguish them from USB 3.1 cables. You cannot use a USB 3.1 cable in place of a Thunderbolt 3 cable.
Thunderbolt cables have gone through multiple generations with varying data transfer speeds, and Thunderbolt 3 is the most current generation as of August in 2018:
Digital coaxial cables are used to send S/PDIF-formatted digital signals between devices, and use RCA connectors. One digital coaxial cable is capable of transferring two channels of uncompressed PCM audio, or compressed 5.1/7.1 surround sound; this is possible due to the fact that digital coaxial cables transmit digital signals, and not analog signals.
The cable you use to connect an AV receiver to your audio interface is a digital coaxial cable with RCA connectors, and the connection port on your audio interface will likely be labelled as "Coaxial" or "S/PDIF".
Fiber optic cables are used to send S/PDIF-formatted, or ADAT-formatted signals between devices. They transmit signal via a series of light pulses. Fiber optic cables can look similar to electrical cables on the outside, but they contain optical fibers that are used to carry light. Fiber optic cables are used frequently for telecommunication purposes over long distances, as well as to provide high-speed data connections. They can transmit multiple channels of audio through a single cable, making them a great option if you're trying to reduce the number of cables in your studio.
The fiber optic cable with TOSLINK connectors pictured above is capable of transmitting S/PDIF-formatted, or ADAT-formatted signal. The ADAT protocol is capable of carrying 8 channels of 24-bit 44 kHz audio, or 4 channels of 24-bit 96 kHz audio through a single fiber optic cable.
The cable you use to connect a multi-channel pre-amp to your existing audio interface is a fiber optic cable with TOSLINK connectors, and the connection port on your audio interface will likely be labelled as "Optical" or "ADAT".
MIDI (Musical Instrument Digital Interface) cables are used to connect a variety of musical instruments, computers, and audio devices together. MIDI cables carry information such as notation, pitch, velocity, vibrato, panning, and tempo. By sending MIDI information from a device like a MIDI keyboard to your computer, you can control devices like software synths.
You can also send MIDI information from your computer to external MIDI-enabled hardware devices. Perhaps you wrote an excellent chord progression using MIDI notes in your DAW, but you want your hardware synth to play the progression. You can send the MIDI information from your DAW to your hardware synth using a MIDI cable, and record the hardware synth's audio outputs back into your DAW.
A word clock cable is a coaxial cable with a BNC connector on each end; it's used to sync the internal clocks of multiple digital devices in your studio. BNC (Bayonet Neill-Concelman) connectors are radio-frequency connectors that use a quick connect/disconnect. By turning the coupling nut a quarter turn on the male connector, it mates with the female connector and forms a secure connection.
Failing to sync the internal clocks of the digital equipment in your studio with a master clock will result in an issue called "audio drift." Hop Pole Studios has an in-depth video on digital clocking if you'd like to learn more about it.
The cable you use to sync the internal clock of a piece of digital hardware (the slave) to the internal clock of another piece of digital hardware (the master) is a word clock cable.
6. Power Cables
Power cables use the AC (alternating current) provided from the wall sockets in your studio to power your equipment. There is enormous controversy over whether or not the quality of your power cables makes a substantial difference to the sonic quality of your equipment. I've read numerous articles backing up each side of this argument, each claiming to have conducted "extensive A/B testing," so unfortunately, I don't feel at liberty to side with one argument over the other as I have not A/B tested power cables of various qualities myself.
The third prong that you find on some power connectors is the ground connector; it provides a way for electricity to discharge from the device that it's powering if a short circuit occurs. Short circuits can lead to devices overheating, or catching fire.
Although I can't vouch for replacing all the power cables in your studio with more expensive ones, I can testify that a quality power conditioner is essential; it can provide "clean power," increase the lifespan of your equipment, and protect your equipment from surges.
The following video by The Engineering Mindset explains how electricity works and demonstrates it in a way that's easy to understand.
7. Cable Management Tools
As your studio grows, cables become increasingly difficult to manage; storing them and keeping them tidy can be quite the challenge. Luckily, some inexpensive, and moderately priced cable management tools can take care of your cable management needs.
Velcro straps are an excellent way of keeping your cables from unraveling. You can pick up velcro straps in numerous different colors, so it’s possible to color code your cables based on the velcro straps you use. There’s no need to spend a ton of money on velcro straps; they’re a utility item, and something simple will suffice.
Keeping your cables tucked away in a box isn’t the best idea; it makes it much more difficult to access them. Also, digging through a crate of cables to find the one you want is a nightmare. You can pick up metal wall hooks from Home Depot for well under $1.
Perhaps you live in an apartment and drilling holes into your walls in order to install hooks won’t go over so well with the building manager. That’s alright because you can store your cables with shoe rack organizers instead! Say what? Let me clarify, I’m specifically referring to those clear shoe rack organizers that hang off the top of your door. You can wrap your cables up, tuck them into the shoe pockets, and not have to worry about getting your damage deposit back.
If you’ve acquired a fair amount of analog equipment, you may want to consider picking up a patch bay; this will allow you to quickly create custom signal processing chains without detaching cables from your equipment. The idea is that you connect everything in your studio to the back of this patch bay, and reroute audio via the open connector inputs in the front of the unit. The patch bay I have uses TRS cables, but higher end patch bays found in commercial studios typically use TT cables.
Snake cables are useful for tidying up behind your rack-mounted equipment; they combine many individual cables into one. If you have a smaller studio they aren't necessary, but as you grow your studio they'll become something that you should take a look at.
8. How to Properly Wrap Cables
You're meant to use an "over-under method" to wrap cables; this prevents the wires within a cable from warping and wearing away over time. The following 1-minute tutorial demonstrates how to wrap audio cables the right way.
9. Tips for Buying Audio Cables
In regards to buying cables, I recommend you avoid expensive audio cables like the plague. If they’re more expensive, they have to be better, right? Not necessarily. Buy cables that are of decent quality, but don’t even think about spending $60 for an XLR cable; that’s outrageous, and that money can be much better spent on something else. The main thing to be concerned about is that the wiring in the cable is soldered correctly to the connectors and that the cable is not defective; this interview with Ethan Winer covers this and other audio myths in more detail.
Sweetwater has a great 3-step tool that will allow you to search for cables by identifying the type of cable you’re looking for, followed by the connector type you’d like on each end.
Want to save money on audio cables? Read "How to Make Your Own Audio Cables" to learn about the tools, supplies, and skills you need to make instrument and microphone cables.