The Music Producer's Guide To Compression: The Music Producer's Guide

The Music Producer’s Guide to Compression

The Music Producer’s Guide To Compression

Published by Stereo Output Limited, company number 11174059

ISBN number 9781999600372

Copyright © Ashley Hewitt 2021

Ashley Hewitt has asserted his right under the Copyright, Designs and Patents Act 1988 to be identified as the author of this work.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright holder except in the case of brief quotations embodied in critical views and certain other non-commercial uses permitted by copyright law.

Introduction

Compression can make or break a piece of music.

Used correctly, compression will give your tracks verve, energy and focus. It will remove unwanted variations in intensity and pull different sonic elements together, making your tracks sound coherent and professional. When used poorly - or not at all - the tracks you make will inevitably fall flat.

Compression touches every facet of recorded music. It is the main reason why a Bowie LP from the 1970s sounds so fundamentally different to that same LP on Spotify, and why contemporary EDM can be such an intensely visceral experience.

Learning about compression and how to use it in the right way is an essential part of the modern music producer’s education. You will not get far in your music production without a good working knowledge of how to make proper use of this powerful effect.

In this book we’ll explore both the traditional functions of compression and the outer edges of its use in contemporary settings. It is not a prescriptive approach filled with rules and formulae, but a useful guide to help you to utilise compression across a broad range of music production contexts.

As you work your way through these pages, you will be encouraged to undertake your own creative approach to the process of compression, gaining vital first-hand experience in the use of compressors within your own projects.

By the end of this book, you will understand:

What compression is, and why producers use it.

The history of compression.

The primary functions of all compressors.

The secondary functions of many compressors.

The fundamental techniques for using compressors.

Classic compression techniques.

The difference between compressing downwards and compressing upwards.

Examples of compression in action in the studio.

Fun ways of using compressors to bring a sense of novelty and uniqueness to your music productions.

Chapter 1:    The Fundamentals of Dynamic Range Compression

1.1: The Nature of Sound Intensity

Compression is classed as a dynamic effect. What this means is that it modifies an audio signal by causing changes to the sound intensity.

Compression was first developed during the advent of military signal technology, when flattening the amplitude of signals was essential to ensure their consistency, such as keeping audio signals at an audible volume whether the speaker was shouting or whispering. Its application to radar technology ensured that returning signals were of amplitude that could be read without mistakes. The subsequent transition of compression to the music studio was a natural progression, where it proved a useful means for adding colour, depth, warmth and punch to a sound.

When understanding compression within the context of music production, the key property we need to focus on is the intensity of sound. Because of the way our ears perceive sound intensity, this is often equated with the sound volume.

As you probably already know, the vibrations of a sound source create a pressure wave that consists of alternating layers of high and low pressure. The human ear detects these changes of pressure and they are heard as sound by the listener.

Here now is an important point: the bigger the deviation of pressure, the greater the intensity of the sound. This is shown in Figure 1.1 below, where wave a depicts a sound wave of higher intensity than b. Notice the difference in their respective amplitudes - the relative height and depth of the waves themselves. The pressure deviation of sound wave a is large, and this is reflected in the large amplitude of the sound wave. In sound wave b this pressure deviation is lower and is reflected in the lower amplitude of the sound wave:

Figure 1.1: Two sound waves. Sound wave a is of higher intensity than sound wave b.

Sound intensity is measured using the Decibel scale, which begins with the quietest sound that the human ear can register. This lowest point is known as the auditory threshold and is conveniently set at 0dB. To put this into perspective, the sound of a light leaf rustling nearby would be roughly 10dB, whilst a whisper would correspond to about 20dB.

When studying the Decibel scale, bear in mind that it is logarithmic. What this means is that an increase of 10dB corresponds to a doubling in the perceived level of volume. A sound intensity of 30dB would therefore be heard to be twice as loud as a sound intensity of 20dB. The need for using a logarithmic scale becomes evident when we consider that the intensity of the sound of a jet taking off is literally over a billion times louder than the sound of a pin dropping on a hard wooden floor.

For music producers, sound intensity is a serious business, not just in terms of music production, but also our wellbeing. Long term exposure to sounds of too high an intensity can permanently damage our hearing. It might surprise you to learn that this damage can occur from prolonged exposure to sounds as low as 70dB, which is far below the human threshold of pain (at around 130-140dB). Always take care of your sense of hearing! It is your greatest asset as a music producer.

Table 1.1 lists some general intensity levels to help you develop a basic idea of the dB scale:

Table 1.1: The intensity levels of different sounds.

Now that we have a convenient way to measure sound intensity, let’s consider some additional concepts that are useful to understand when studying compression. The first of these is the concept of dynamic range.

1.2: Dynamic Range

Hearing a sound depends upon two factors: the loudness of the sound itself and the background level of sound (also known as the noise floor). Put simply, you cannot hear a leaf rustling in a storm, and you cannot hear a quiet conversation at a rock concert.

This leads us to an important observation. The level of the sound alone is not the main factor - it is the level of the sound relative to the noise floor that determines whether or not it can be heard. The difference in intensity between the noise floor and the individual sound is called the dynamic range (not