Introduction To Live Sound

Introduction To Live Sound

Live sound engineers play a crucial role at live events. Both music events as well as corporate. Without these engineers, the gigs we go to wouldn’t exist, or would sound bad and potentially cause damage to the crowds hearing!

In this blog post I’ll talk about the roles and responsibilities of live sound engineers and introduce the terminology used in this line of work. Then I’ll finish off with a basic overview of a common rig setup and layout in a diagram. If you’re interested in getting into this more technical side of the music industry or just interested in general, keep reading to find out more. This will be the introductory blog for a series of live sound related posts to follow.

Roles and Responsibilities of a live sound engineer: 

Put simply, live sound engineers have the responsibility of making sure that the artist or band they’re working with, are sounding as they should and even a bit better. So, they create a well-balanced mix that can be heard by the audience. This is called the “Front of house (FOH)” mix. 

As well as the FOH mix there needs to be a “monitor” mix, which is what the band or artist hears on stage. This can be used through monitor wedge speakers on stage or through in-ear monitoring systems (IEM’s). 

Most big venues will have 2 engineers. One for FOH and one for monitoring. So, the FOH engineer will work on the sound that the crowd hears, and the monitoring engineer will make sure that the band or artists have enough levels in their stage monitors. 

Some venues will only be using one mixing desk though, so the engineer will control the FOH sound as well as the monitors.

Think of live sound engineering being like studio production but in real time. This means that the engineers will need to react quickly to any potential problems, such as feedback and troubleshoot any issues as fast as they can. In worst case scenarios, bad feedback can cause damage to people’s hearing, which is why competency, preparation and organisation are very important in this line of work.

Common basic terminology and equipment used in Live sound:

-Rig: This is a term for the overall system and equipment that is used.

-Desk: This refers to the mixing desk for Front of house or monitoring. 

-Amps: These are the amplifiers that send signal to the speakers.

-Subs: These are the speakers that project the low end or bass from the music.

-Tops: These are the speakers that project the midrange and high-end treble from the music.

Some more complex set-ups will have more speakers for different frequencies, but I’ll talk more about that in a future post!

-Stage box: This is where the microphones and instruments on stage are plugged into. This is then linked to the mixing desk with a multicore or ethernet cable, depending on whether the rig is analogue or digital. Multicore is for analogue and ethernet is for digital.

-XLR cables: These are standard 3-pin microphone cables.

-SpeakOn cables: These are the industry standard speaker cables.

-Mics: Microphones

-Monitors/Wedges - These are on-stage speakers for the artists to hear themselves.

-In-ear monitors (IEM’s)- In-ear device, much like headphones, for the same purpose as the monitor wedges.

-Front of house (FOH): See diagram below.

-Stage right and stage left: This is the opposite of FOH. So, stage right would be FOH left etc.

-Feedback - This is the unpleasant and unwanted sound caused by the on-stage microphones picking up and looping the sound coming from the monitor wedges. This doesn’t happen with IEM’s. Too much gain or having amps too loud on stage can have this effect as well as unwanted frequencies. 

-Pre fader level (PFL): This is the amount of signal coming into each channel before the volume fader without any processing such as EQ or compression. This is also referred to as gain. See video example of PFL and faders.

-Post-fader: This refers to the signal after it has been processed through the channel. For example, if you have applied EQ and reverb to a specific channel, this will be heard “post-fader”.

Analogue vs Digital:

Most professional venues use a digital setup these days, as it’s more of an all in one package. The effects and processing are built into the desk and the signal comes from the stage via one ethernet cable as opposed to a time-consuming multi-core cable that would be used with an analogue desk. Also, with an analogue rig, you need external hardware and effects processors, which can be very cumbersome and heavy. It comes down to personal preference at the end of the day, but I would recommend trying both as it’s good to learn how to use the analogue processors first. For example, using analogue graphic equalisers and compressors are more hands on and “out in the open”. Whereas, the effects processors on digital desks are more discrete and may not seem as obvious.

Common rig setup and layout:

This introductory blog has outlined why and how live sound is a necessary and important part of the music industry, as well as some of the terminology and equipment used in this field. The next blog in this series will delve deeper into live sound and we will get into more detail of specific areas, including more diagrams and practical examples.

By David Griffiths.