Audio Terminology & Glossary

A comprehensive reference guide to common audio concepts, connections, and terminology used in live audio production.

Connectors

Understanding the physical connectors is the foundation for understanding audio signal flow. The same connector type can carry different kinds of signals depending on how it's wired.

XLR (Cannon Connector)

3-pin: Most common for balanced audio
Professional standard for microphones
Male: Output (microphones, console outputs)
Female: Input (console inputs, powered speakers)
Locking connector - won't pull out accidentally

XLR Balanced Audio (3-pin):
     ___
    /   \     Pin 1: Ground/Shield
   | 2 1 |    Pin 2: Hot (+)
    \ 3 /     Pin 3: Cold (-)
     ---

1/4" Phone/TRS Connectors

These connectors are extremely versatile. The same physical connector can carry different signal types depending on how it's wired!

TS (Tip-Sleeve)

Two conductors (unbalanced)
Used for: Instrument cables, patch bays, unbalanced line connections
Also called: Phono plug, guitar cable connector

TS - Unbalanced Mono:
    _______________
   |______^|_______|
      Tip   Sleeve
       |      |
    Signal  Ground

TRS (Tip-Ring-Sleeve)

Three conductors (can be balanced OR stereo)
Used for: Balanced line connections, headphones (stereo), insert cables

IMPORTANT: The same TRS connector is used for two completely different purposes:

    TRS - Balanced Mono:            TRS - Stereo Unbalanced:
    ___________________               ___________________
   |____^|_____|_______|             |____^|_____|_______|
     Tip  Ring  Sleeve                 Tip  Ring  Sleeve
      |     |      |                    |     |      |
     Hot  Cold  Ground                Left Right  Ground
     (+)   (-)                        (L)   (R)

Example: XLR to TRS adapter       Example: Headphones
for balanced line-level           carrying stereo audio

The key difference:

Balanced Mono: Tip and Ring carry the same signal with opposite polarity
Stereo: Tip and Ring carry two independent signals (left and right channels)

TRRS (Tip-Ring-Ring-Sleeve)

Four conductors
Used for: Headsets with microphones, smartphone audio
Commonly used with phones/computers which support a headphone jack

TRRS - Headset with Mic:
    _________________________
   |____^|_____|_____|_______|
     Tip  Ring1 Ring2 Sleeve
      |     |     |      |
    Left  Right  Mic  Ground

RCA

Unbalanced consumer-level connector
Red/White pairs (stereo)
Common on consumer playback devices
Not ideal for professional theatre use

RCA - Unbalanced:
     ___
    | | | Center pin: Signal
    |___| Outer ring: Ground

Speakon

Locking speaker connector (Neutrik brand)
Used exclusively for speaker connections
More reliable than 1/4" for high-power applications
Various configurations (2-pole, 4-pole, 8-pole)

3.5mm (1/8") Mini Jack

Smaller version of 1/4" connector
TRS configuration for stereo
Common for: Smartphones, laptops, consumer devices, in-ear monitors
Often used with adapters in professional settings
Same wiring principles as 1/4" TRS (can be stereo or balanced mono)

Dante/Ethercon

RJ45/Ethernet connector for digital audio networking
Locking version (Ethercon) preferred for stage use
Carries multiple audio channels over Cat5e/Cat6 cable

Signal Types

Now that you understand the physical connectors, let's explore the different types of signals they carry.

Balanced vs. Unbalanced

Now that you've seen the connectors above, here's how signals flow through them:

Balanced signals use three conductors (positive, negative, and ground) to carry audio. The signal is sent on two wires with opposite polarity, which allows interference picked up along the cable to be canceled out at the receiving end. This provides better noise rejection and allows for longer cable runs. Common in professional audio.

Connectors: XLR (3-pin), TRS (balanced mono configuration)
Example: Microphone → XLR cable → Mixer

Unbalanced signals use two conductors (signal and ground). More susceptible to electromagnetic interference and noise, especially over longer distances. Typically limited to runs under 20 feet in professional settings.

Connectors: TS, RCA, TRS (stereo configuration uses unbalanced signals)
Example: Guitar → TS cable → Amplifier

Signal Levels

Mic Level (-60 to -40 dBu)

The weakest audio signal, produced by microphones
Requires pre-amplification before mixing or processing
Very sensitive to noise and interference

Line Level (-10 dBV or +4 dBu)

Standard operating level for most audio equipment
-10 dBV: Consumer/prosumer equipment (unbalanced)
+4 dBu: Professional equipment (balanced)
Approximately 10-12 dB difference between the two standards

Instrument Level

Between mic and line level
Typical output from electric guitars and basses
Requires DI (Direct Input) box to convert to mic/line level

Speaker Level

High-power amplified signal from power amplifiers
Designed to drive loudspeakers
Never connect speaker-level outputs to line-level inputs!

Connections & Cables

Understanding how cables are wired internally helps explain why certain connectors work for balanced vs. unbalanced signals (see Connectors above).

Balanced Connections

Use three conductors to provide noise rejection:

Hot (Positive): Carries the audio signal
Cold (Negative): Carries inverted audio signal
Ground (Shield): Provides grounding and shielding

Best for: Long cable runs, stage-to-booth connections, mic cables

See the XLR and TRS (balanced mono) diagrams above for wiring details.

Unbalanced Connections

Use two conductors:

Tip: Carries the audio signal
Sleeve: Ground/shield

Best for: Short connections, patch bays, instrument cables

See the TS and RCA diagrams above for wiring details.

Cable Types

Mic Cable

Uses XLR or TRS (balanced mono) connectors
Balanced connection - three conductors
Typically 20-100 feet in theatre applications
Quality matters - cheap cables add noise

Instrument Cable

Uses TS connectors
Unbalanced connection - two conductors
For guitars, basses, keyboards
Keep runs short (under 20 feet when possible)

Speaker Cable

Uses Speakon or 1/4\" TS connectors (high-power rated)
Heavy gauge wire to carry amplified signals
Never use for mic or line-level signals
Not interchangeable with instrument cables

Snake/Multicore

Multiple channels in one cable bundle
Typically uses XLR connections at each end
Stage box to mixing console connection
Can be analog or digital

Equipment Terms

DI Box (Direct Input/Direct Injection)

Converts unbalanced, high-impedance instrument signals to balanced, low-impedance mic-level signals. Essential for connecting guitars, keyboards, and other instruments to the mixer.

Active DI: Requires power (battery or phantom power), provides gain Passive DI: No power required, simple transformer-based

Phantom Power (+48V)

DC voltage sent through mic cables to power condenser microphones and active DI boxes. Safe for dynamic mics but can damage ribbon mics - always check before engaging!

Preamp/Gain

The input stage that amplifies mic or line-level signals to optimal operating level. Proper gain staging is critical - set gain first, then adjust faders.

Compressor

Reduces dynamic range by automatically lowering loud signals. Helps keep vocals consistent and prevents distortion.

EQ (Equalizer)

Adjusts the balance of frequency content in a signal. Used to:

Reduce feedback
Improve clarity
Shape tone
Remove unwanted frequencies

Gate/Noise Gate

Automatically mutes a channel when the signal falls below a set threshold. Reduces bleed from other sources and background noise.

Aux Send/Auxiliary Send

Independent mix output from the console used for:

Stage monitors: Pre-fader sends
Effects (reverb, delay): Post-fader sends
Recording feeds: Pre or post-fader

Main/Master Fader

Controls the overall output level of the main mix going to the house speakers.

Group/Bus

Submix that combines multiple channels, allowing control of several inputs with one fader. Example: All choir mics on one group.

Matrix

Output that can combine multiple buses/mains in custom ratios. Used for: Fill speakers, delay towers, lobby feeds.

Mixing Concepts

Gain Staging

The process of setting proper signal levels at each stage of the audio chain:

Set input gain (preamp) so meters show healthy signal without clipping
Adjust channel faders for balance
Set master fader to unity (0 dB) or slightly below

Feedback

The howling/squealing sound when amplified sound from speakers re-enters a microphone and creates a loop. Controlled by:

Proper mic placement and technique
EQ (notching out feedback frequencies)
Reducing monitor/speaker volume
Using directional microphones

Headroom

The difference between the normal operating level and the maximum level before clipping/distortion. Always leave headroom to prevent distortion during unexpected peaks.

Phase

The timing relationship between two audio signals:

In Phase: Signals reinforce each other (louder)
Out of Phase: Signals cancel each other (quieter)
Common issue with multiple mics on one source

High-Pass Filter (HPF) / Low-Cut Filter

Removes low frequencies below a set point (typically 80-100 Hz). Essential for:

Reducing rumble and handling noise
Minimizing stage vibrations
Cleaning up vocal mics

Channel Strip

The collection of controls for a single input: gain, EQ, aux sends, pan, fader, etc.

Unity Gain (0 dB)

The reference level where no gain or attenuation is applied. Faders marked "0" or "U" are at unity.

Acoustic Terms

Feedback Frequency

The specific pitch at which feedback occurs. Can be identified and reduced with precise EQ adjustment.

Frequency Range

Sub-bass: 20-60 Hz (felt more than heard, rumble)
Bass: 60-250 Hz (warmth, body, power)
Low Mids: 250-500 Hz (can be muddy if excessive)
Mids: 500 Hz-2 kHz (presence, voice fundamentals)
Upper Mids: 2-4 kHz (clarity, intelligibility)
Presence: 4-6 kHz (articulation, edge)
Brilliance: 6-20 kHz (air, sparkle, sibilance)

Proximity Effect

Bass boost that occurs when a directional microphone is used very close to the source. Common with vocals on cardioid mics.

Room Modes/Standing Waves

Resonant frequencies in a room caused by reflections between parallel surfaces. Can cause uneven bass response.

Reverberation (Reverb)

The persistence of sound after the source stops, caused by reflections in a space. Adds depth and space to dry signals.

Delay/Echo

Distinct repetition of sound. Used for:

Creative effects
Timing synchronization (delay towers)
Depth and space

Digital Audio

Sample Rate

How many times per second digital audio is measured (e.g., 48 kHz = 48,000 samples per second). Higher = better quality but larger file sizes.

44.1 kHz: CD quality
48 kHz: Professional video/broadcast standard (most common in theatre)
96 kHz: High-resolution audio

Bit Depth

The number of bits used for each audio sample. Determines dynamic range:

16-bit: CD quality (96 dB dynamic range)
24-bit: Professional standard (144 dB dynamic range)
32-bit float: Maximum headroom, virtually impossible to clip

Latency

The delay between input and output in digital systems. Critical for:

Live monitoring (musicians need <10ms)
Digital mixing consoles
Wireless systems

Dante

Audio networking protocol that carries multiple channels of audio over standard Ethernet. Used extensively in modern theatre installations.

Word Clock

Synchronization signal that keeps digital audio devices operating at exactly the same sample rate. Prevents clicks, pops, and audio drift.

A/D Converter (Analog-to-Digital)

Converts analog audio signals (microphones, instruments) to digital data for processing.

D/A Converter (Digital-to-Analog)

Converts digital audio back to analog signals to drive speakers and headphones.

Quick Reference Tables

Common Connector Summary

Connector	Type	Use Case
XLR (3-pin)	Balanced	Microphones, professional line connections
1/4" TRS	Balanced/Stereo	Balanced line, headphones, inserts
1/4" TS	Unbalanced	Instrument cables, patch bays
3.5mm TRS	Stereo/Balanced	Consumer devices, IEM, computer audio
RCA	Unbalanced	Consumer playback devices
Speakon	Speaker	Powered speaker connections
Ethercon/RJ45	Digital	Network audio (Dante, etc.)

Signal Flow Reminder

Microphone → Mic Cable (XLR) → Mixer Input (Preamp/Gain) → 
Channel Strip (EQ, Dynamics) → Fader → Master Bus → 
Output → Power Amp/Powered Speaker → Audience

Tips for Success

Always start with gain, not faders: Set input gain properly first
Label everything: Cables, channels, connections
Use balanced connections whenever possible for better noise rejection
Keep cable runs neat: Reduces noise and trip hazards
Don't coil cables too tightly: Damages the conductors and shielding
Check phantom power: Before connecting ribbon mics or devices that don't need it
High-pass everything: Except bass instruments and kick drums
Less is more with EQ: Cut before boost
Ring out monitors properly: Before rehearsal to prevent feedback
Document your setup: Makes next time easier