PA System Basics

The following is intended as a reference to terminology used in a basic PA System (Public Address System) setup.  If you are new to the world of PA Systems these terms may not yet be familiar but you are likely to come across them, both on this site and elsewhere.

Amplifier  The part of the system that amplifies the sound.
Channels  Refers to the number of input/output sources.

• ‘Input’ usually refer to signals coming into the amplifier/mixer (microphones, guitars, drums keyboard or other equipment which needs to be amplified or mixed).
• ‘Output’ usually refer to those signals leaving the amplifier/mixer (speakers/monitors etc.)

FX  An electronic circuit or effects unit , to alter the original audio signal for a specific period of time. ( Delay,Echo, Reverberation etc.)
Equaliser  Used to tailor specific frequencies of the sound, Often referred to as “EQ” designed to control the tone heard from the speakers.
Fader  Audio level control. Usually used to adjust the final output from a specific channel or master output. Microphone volumes and track levels can be controlled independently via the input channels
Jack  Single pole unit used on ‘input/output’ plugs/sockets.
Level  Signal voltage, (volume, strength or power.)
Gain  Adjusts the signal strength
Line-In  (Input/Return) – signal enters the amplifier/mixer.
Line-Out  (Output/Send) – signal leaves the amplifier/mixer.
Master Volume  The master volume is used to increase or decrease the sound of the overall performance (microphone and instruments simultaneously.)
Mixer  Equipment to enable you to control various settings such as the Gain of individual microphones/instruments, pan, bass, midrange and treble, on-board effects such as reverb, chorus, delay, echo etc. Many mixers are referred to as having 6, 8, 12, channels etc. This relates to the number of different audio sources that can be connected to the mixer.
Monitors  Additional speakers, commonly placed in front of the performer, enabling them to clearly hear themselves on stage.
Pan  Places the specific audio source in a desired balance in the mix relative to volume sent between left and right speakers. (if in doubt leave the knobs central).
Phantom Power  To provide power for condenser microphones from the mixer. Most quality microphones are designed to use +48 VDC phantom power.
Return  A mixer line input dedicated to returning sound from external devices such as reverb units, echo units etc.
Phono Plug  Commonly found on consumer audio equipment.
XLR Connector  Three-pin connector used in audio for transmitting signal (microphones etc.)
SpeakON  Custom designed (Neutrik) Loudspeaker terminal found on many loudspeaker enclosures

Yes, I know these aren’t in alphabetical order and I know this isn’t an exhaustive list.  Its just a quick reference guide to help people understand articles written on this site and to understand and compare products from the PA Systems section of Soundsavers.