XLR to XLR Microphone Cable: Wiring, Length and Specification
Quick Answer / Summary: An XLR to XLR microphone cable is a balanced lead with a three-pin connector at each end, two twisted signal conductors, and an overall shield connected to pin 1. Pin 2 is in phase and pin 3 is inverted. For microphone-level signals, low-capacitance cable supports runs up to roughly 100 m; for high-impedance sources keep the run under about 5 m. Specify length, conductor count, shield type and jacket compound, since those determine the usable life more than the connector brand does.
An XLR to XLR microphone cable is the standard balanced lead in professional audio: the same three-pin interface at both ends, two signal conductors and a shield in between. Its apparent simplicity is exactly why it is specified badly. Connector grade, conductor gauge, shield construction and length all change how the cable behaves on a long run or under stage abuse. This guide covers the wiring, the electrical limits that decide usable length, and the specification points that separate a lead that lasts a season from one that lasts a decade.
The Electrical Job the Cable Does
The cable carries a low-level differential signal from a source to a high-impedance load, and it must do so without adding noise, losing high frequencies or picking up interference. Two identical conductors carry the signal in opposite polarity so that interference coupling into the pair cancels at the receiver, and the shield drains what remains. Because microphone signals are small, the cable is part of the signal chain rather than a passive accessory.
Common-Mode Rejection in Practice
Rejection depends on the two signal legs staying electrically similar. A pair that is twisted tightly and kept twisted to the solder cups couples interference into both legs nearly equally, which is what allows the receiver to cancel it. Untwisting the pair at the connector, or using a cable whose two conductors have very different geometry, erodes that symmetry.
Capacitance and High-Frequency Loss
Cable capacitance forms a low-pass filter with the source impedance. A typical low-capacitance microphone cable sits around 50 to 100 pF per metre, which keeps a 100 m microphone run acceptable. A high-capacitance lead of the same length will shave the top end, which is heard as dullness rather than as obvious distortion.
Length, Gauge and Environment
Length decisions should start from the source impedance and the cable capacitance rather than from habit. Microphone-level balanced signals tolerate long runs, line-level balanced signals tolerate them comfortably, and unbalanced signals do not. Once the length is fixed, choose the gauge and shield to suit the way the cable will live: coiled and walked on, or fixed inside a wall and never touched again.
Stage Leads and Fixing Leads
A stage lead needs a flexible jacket, a tight bend radius and strain relief that survives repeated coiling. An installed lead needs a jacket rated for the space, and it can trade flexibility for lower capacitance and better shielding. Using a stiff installation cable as a stage lead usually ends with a broken shield at the boot within a season.
Runs That Cross Power
Where a cable must run alongside mains wiring, crossing at right angles and keeping separation reduces induced noise. Balanced construction and a tight braid shield handle most of what remains, which is why installed audio looms are normally specified with a high-coverage braid rather than a loose spiral.
Writing the Specification
A complete microphone cable specification lists the connector type and gender at each end, the length, the conductor count, the shield construction, the jacket compound, and the colour or marking scheme needed to identify the batch. It also states the tests to be performed, because continuity on three contacts and a flex test at both boots catch the faults that reach the customer otherwise.
The Checks That Belong in the Specification
Require continuity on pins 1, 2 and 3 end to end, no continuity between pin 2 and pin 3, shield continuity to pin 1 at both ends, and a flex test of at least a few hundred cycles at each boot with continuous monitoring. Ask for the test to be performed on every unit rather than on a sample where the volume justifies it.
Marking and Batch Traceability
Heat-shrink labels at each end with a batch code cost very little and make a field failure traceable. Where a customer runs several hundred leads, marker rings of different colours on both ends halve the time spent tracing a channel during a show or a session.
XLR to XLR Microphone Cable Specification Reference
| Parameter | Typical Value | Effect |
|---|
| Conductors | Two, twisted | Two legs are required for balance; a single conductor plus shield cannot reject noise |
| Capacitance | About 50 to 100 pF per metre | Higher capacitance rolls off high frequencies on long runs |
| Usable length, microphone level | Up to about 100 m | Set by source impedance and capacitance |
| Usable length, high impedance | Under about 5 m | Balanced rejection is not enough to save a high-impedance source |
| Shield | Braid or dense spiral to pin 1 | Handles interference the twisted pair does not reject |
| Tests | Pin continuity, pin 2 to pin 3 isolation, flex at both boots | Catches connector faults that continuity alone misses |
Real-World Application Scenarios
Typical scenarios: standard stage microphone leads in a fixed gender convention; studio tie-lines between a live room and a control room; OEM supply to a microphone brand that requires its own marking scheme; installed podium and pulpit microphone wiring in a house of worship; and rental stock where cables are cycled through hundreds of shows per year.
Recommended Internal Resources
Editorial Note: Internal linking recommendation: (1) Connector wiring – https://zh-zong.com/xlr-connector-cable-guide/ (anchor: XLR connector cable wiring and gender rules); (2) Microphone cluster – https://zh-zong.com/microphone-cable-types-guide/ (anchor: microphone cable types compared); (3) Related adapter – https://zh-zong.com/xlr-to-3-5mm-cable-guide/ (anchor: XLR to 3.5mm cable guide for consumer and camera inputs); (4) Conversion – https://zh-zong.com/contact/ (anchor: contact the sales engineering team for XLR to XLR microphone cable programs with length and shield type stated per SKU).
Frequently Asked Questions (FAQ)
Q: Is an XLR to XLR cable a microphone cable?
A: Yes, when it uses two signal conductors plus a shield. The term describes the connectors rather than the application, so the same lead can carry microphone, line-level or other balanced signals within the limits of its capacitance and shielding.
Q: How long can a microphone cable run be?
A: Microphone-level balanced signals can run up to about 100 m with low-capacitance cable. High-impedance sources should stay under about 5 m regardless of the connector, because the cable cannot reject noise the way a balanced low-impedance circuit can.
Q: What should I test on a new microphone cable?
A: Continuity on pins 1, 2 and 3 end to end, no continuity between pins 2 and 3, shield continuity to pin 1, and a flex test at both boots with continuous monitoring. These four checks cover the majority of manufacturing faults.
