Basic building blocks - how a PA system connects together

The diagram below shows the parts of a PA system and how it all connects together.

Inputs to a PA system - voice or music source or instrument such as guitar, bass, keyboards, drums
The mixing desk is the hub of the PA system allowing you to mix the sound and control the volume
The monitors allow the singers and musicians to hear what they are playing. They can be floor monitors, in-ear monitos or can be personal monitors attached to the microphone stand
If the speakers are active you do not need a power amplifier or a powered mixer. If the speakers are passive you need either a power amplifier or a powered mixer

Source

These are the main sound sources (instruments and vocals) that you want to amplify through the PA. Typically, these would be microphones and keyboards but could also include electric/acoustic guitars, bass guitars, drums or CD players.

Mixer
 

Depending upon your choice, the mixer (mixing desk) can be

Click to view passive (un powered mixers) Click to view active (powered) mixers
Passive
Un-powered, requiring active speakers or a separate power amplifier.
Active
Powered, requiring passive speakers.

Inputs
The mixer is the device for balancing the volume between the vocals and the various instruments. Each input goes into one channel of the mixing desk. Some mixers have FX (special effects processor) built into the mixer, so you can apply special effects (such as reverb) to any of the channels.
Outputs
If the mixer does not come with FX they will have an effect (FX) send/return facility so that you can process individual instruments with FX such as reverb or delay via a DSP - Digital Sound Processors. An additional facility on a mixer is a monitor/foldback send button. This allows you to send and control the signals to the monitor speakers.

Monitors
 

If you are playing at anything other than the lowest volume, then it will be difficult to hear what is coming out of the PA speakers when you are on stage. Monitors (also known as foldback) help you to hear better and also help you to sing in tune!

Click to view monitorsMonitors can be powered or non-powered. We would always suggest powered monitors as you can control the level of the monitors from the stage. If you have un-powered monitors then you will need a separate monitor amplifier. An alternative to stage monitors are in-ear monitors - less gear to carry around!

Amp

If you are not using powered (active) speakers or a powered mixer you will need a Power Amplifier, matched to the output of the two speakers. See the Matching Ohms page for more information about this.

Speakers
 

The are the main front of house (FOH) speakers. These can either be 

Click to view passive speakers Click to view active speakers
Passive
Un-powered, connected to the amplifier)

Active
Powered, connected directly to the mixing desk

 

   

 

Basic set up using a snake/multicore

A set up using a snake allows a sound engineer to mix the sound from the back of the hall. A typical set up is shown below.

Basic PA system set up using snake / multicore



Mixers Limitations
 

Using a snake precludes the use of a powered mixer as you can not put the output of an amplifier down a snake/multi-core cable.

Amplifier positioning
 

The amplifier must be located on the stage area and take the line outs from the mixer via the snake. You may however use either an amplifier plus passive speakers or powered speakers.

Source cable runs
 

Click to fill in our simple enquiry formIn order to use a snake, any connected source instrument should be able to either use a balanced cable (e.g. microphones) or be at line level (e.g. keyboards). If you put the output of a guitar down a long cable run, you will loose signal strength and high frequencies.

If you are connecting an acoustic guitar directly which does not have a low impedance/balanced output, then you will need to deploy a Direct Injection (DI) Box.

Cables, snakes and DI boxes are available in the Online Shop - click here.
 

Need help and advice?
 

Give us a ring on 01375 892317 if you need any help or email enquiries@whatpa.co.uk