Subtractive Synthesis And Waveforms in Music

Ever watched a Youtube video on music production and come across lines like

  • ‘If we just zoom in here on the waveform…’
  • ‘…If we look at the waveform here…we can see the transient on the kick…’
  • ‘If you open up [enter any VST name here] and start with a square wave…’
  • ‘.. on oscillator A we have basic sin wave and on oscillator b with a triangle wave…’

If there’s one concept you’ll keep coming across over and over again – it waveforms. From the sample you purchase from Loopmasters to the sound you create in your favourite VST’s they’re everywhere.

But if you’re just starting out in music – you’ll rightly ask the question…

What are waveforms?

Audio Waveforms vs Basic Waveforms

For sake of simplicity we can split waveforms into two cetgories;

  • Audio Waveforms
  • Basic (or subtractive) Waveforms

On a general level waveforms are just simple graphs that show changes over time. These changes are measured through postive and negative signals using a zero-crossing point as the reference.

Audio Waveforms

Audio waveforms are the waveform you come across in any audio you’ll see in your DAW. They can be short clips or they can span entire tracks or even movies.

They are a combination of tens of thousands of changes over a specific  period of time.

Subtractive (Basic)

Basic or subtractive waveforms are far less complex. So why do we need to know about them? Well, taking a basic waveforms we can construct and design our own unique sounds to use in our tracks. While it’s entirely possible to create bass or lead sound you can even go as far to create your own sounds that mimic a kick drum or snare for example.  Most top level synths offer a range of waveforms you can use to start shaping your sounds.

Quick Side Note: Harmonics

Harmonics give different waveforms their unique identity. A sound is  made up of what’s called the ‘Fundamental Frequency’ and a series of tones above this frequency that we call ‘harmonics’.

If we take a guitar for example; the harmonic ‘content’ of the sound produced from the guitar can be a direct result of the size and dimensions of the guitar, the way in which the guitar strings are struck and even the type of material the guitar is made from.

Simply put: Most instruments produce various frequencies to give it it’s unique sound. These frequencies when grouped together are better known as the instruments harmonics.

In regards to waveforms, the harmonic content of each waveform differs depending on the waveform you’re using.

There a 4 basic waveforms; sin wave, square wave, triangle wave and sawtooth.

  • Sin Wave: Commonly Used for: bass, leads and FX
  • Square Wave: Commonly used for: Bass, Leads and Wind Instruments
  • Triangle Wave: Commonly used for: sub bass, pads
  • Sawtooth / Saw Wave: Commonly used for: aggressive sounds, basses and and warm pads

Subtractive Synthesis: Amplitude vs Frequency

When it comes to waveform there are two main principles to be aware of in regards to the vibration;

  • The Amplitude of the vibration
  • The Frequency of the vibration

The amplitude is the size of the vibration and will ultimately determine the loudness of the sound. Take our zero-crossing point again. The higher and lower the waveform goes the louder to goes.

The frequency refers to how fast the vibration is. This controls the pitch of the sound. The best way to identify this on a waveform is to see the distance between each positive and negative signal. The closer they are together the higher the pitch.

You’ll see frequency referred to as Hz – this measures how many wave cycles there are in each second.

  • 2Hz = 2 wave cycles in a second
  • 10Hz = 10 wave cycles in a minute