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A Complete Guide to Cables and Connectors for Live Performances
Cables are essential for connecting instruments, microphones to amplifiers, speakers, or effects units. However, many of us often struggle with the variety of cable types at the beginning. Questions like whether to use TRS or XLR for monitoring or how to adapt specific input/output connections are frequently asked. In this article, we’ll walk you through the most commonly and frequently used cables.
The Most Common for Instruments: 1/4″ Jack (6.3mm)
The 1/4″ jack is one of the most common plugs. Some might refer to it as 6.3mm or round up to 6.4mm depending on the Imperial or metric system, but they all refer to the same type of jack. Instruments like guitars, basses, and keyboards use this cable to carry signals. When buying and using these cables, it’s important to distinguish between TS and TRS connectors. The difference lies in the rings on the plug tip: one ring for TS and two rings for TRS.
TS (Tip-Sleeve)
TS connectors are the standard type used for most instruments. They are characterized by having a single ring on the plug, they are also the typical choice for guitars and basses. The structure consists of two conductors: a Tip for the signal and a Sleeve for the ground. This configuration transmits mono, unbalanced signals, which are susceptible to electromagnetic interference over long distances. If you ever hear radio signals or other noise while playing guitar at home alone, it is usually due to inadequate shielding of the cable. High-end (and often more expensive) cables typically emphasize superior internal shielding to minimize noise and maintain sound quality.
TRS (Tip-Ring-Sleeve)
TRS connectors are used for stereo output or balanced signal transmission. TRS wiring is built based on TS wiring by adding another isolating ring between the tip and sleeve, allowing the single cable to transfer two signals.
TRS cables are suitable for instruments like keyboards, synthesizers and electronic drums that can output left and right channels separately. Meanwhile, TRS cables are commonly used for transmitting balanced signals in devices such as microphones, studio monitors, and audio interfaces. This type of cable is often seen in professional settings to reduce noise and ensure high-quality signal transmission.
So, Is TRS balanced or Stereo?
It is important to understand that stereo and balanced signals are different. Stereo refers to two or more independent signals sent to corresponding speakers to simulate what human ears perceive in a real space. In contrast, a balanced cable use two signal wires, both carry an identical mono signal but in opposite polarity. These signals are then processed through a differential amplifier, which cancels out noise by inverting and combining them, making it ideal for long-distance transmission. A TRS connector, with three internal conductors, can handle either balanced or stereo signals. Whether TRS is transmitting a stereo or balanced signal depends on the specifications of the connected equipment. For instance, Cloudvocal’s ISOLO stage receiver provides both balanced and unbalanced outputs, allowing users to choose based on their needs. In some audio equipment, a single TRS jack may offer stereo output, requiring a TRS-to-dual-TS Y cable for stereo playback.
Guitars and basses typically use TS connectors. This is partly because their pickups, especially early passive coil designs, is the source of significant noise, and these instruments are usually played close to the amp. Additionally, since they are mono instruments, unbalanced signals are more practical and remain the standard.
Common in Home Audio: The 3.5mm Connector (1/8″ jack)
If the 6.3mm connector is considered the standard for musical instruments, then the 3.5mm connector is undoubtedly the most common audio plug in everyday life. You can almost found everywhere on headphones and mobile phones (well…almost), it has also become a staple for camera microphones in the age of audio and video streaming. While TRS stereo 3.5mm cables are something you must have come across, there are also alternatives of the connectors.
TS connectors, for instance, were often used with old radio headphones. Older cassette players sometimes had a mono-stereo switch, and using TS headphones on stereo devices would result in audio coming from only one side or the same sound coming from both sides.
A TRS connector is used for stereo audio equipment and is common in everyday music-listening devices. It’s also the standard for connecting microphones to cameras for audio recording. However, one detail to look out is that some 3.5mm jacks use a third type, known as TRRS. This can lead to issues like no sound or excessive noise cracles when trying to connect a camera microphone directly to a smartphone due to incompatible connections.
TRRS (Tip-Ring-Ring-Sleeve) Connectors
TRRS connectors, distinguishable by their three rings, add an extra channel for microphone signals to the standard stereo output. This type of connector is commonly found on smartphone headsets with built-in microphones and on microphone headsets used for live streaming.
Adapting 6.3mm and 3.5mm Connectors
Under specific circumstances, 6.3mm and 3.5mm connectors can be adapted for different uses. For example, many monitoring headphones include a 6.3mm TRS to 3.5mm TRS adapter, allowing for easy switching between devices while maintaining a clear stereo signal. However, when converting between connectors with different pin configurations (like TRS and TS), you should carefully research the signal pin definitions for both input and output. Misconnection can lead to issues, such as sound only coming from one side, flotating noise or weak signals. Many 3.5mm TRS to 6.3mm TS adapters share these problems due to differences in signal pin definitions.
XLR Connectors (Cannon Connectors)
Named after their inventor, XLR connectors are also known as Cannon connectors. They are standard in pro audio, particularly for microphones, which also use XLR connections for phantom power transmission. XLR connectors are also found on mixing consoles and PA systems. The three internal pins transmit balanced signals, reducing noise interference through phase cancellation, ensuring noise free signal. However, XLR cables only cary mono balanced signals, so separate XLR cables are required for stereo output.
Combo Jacks
Since instruments and microphones frequently use 1/4″ jacks and XLR connectors, combo jack is the design that can take both connectors. We often see combo jacks on audio interfaces, mixers, and instrument amplifiers. Although these jacks accepts both type of connectors, one important thing that users ofter omit is that the signal level differences between a mic source and line source is significant. We will cover this in our future article.
USB: A Digital Age Essential
USB, or Universal Serial Bus, is ubiquitous in modern life and a crucial connector for audio interfaces, computers, and mobile devices for recording and streaming. Although not specifically designed for audio, USB uses differential signaling to transmit digital data, offering strong interference resistance by transmitting binary signals through paired D+ (positive) and D- (negative) lines.
USB-C has addressed many issues, like plug orientation, and is becoming the standard for electronic devices. However, during this transitional phase, you must pay attention to features and communication protocols. Variations like USB 3.2, Thunderbolt 3, and DisplayPort can lead to compatibility and functionality confusion: not all USB-C cables support PD fast charging, nor do all USB-C ports provide video output, so distinguishing between these features is crucial.
