Waveforms

The 4 basic waveforms. You could find them in pretty much any synths.

We’ll start with waveforms, as that’s the basis of every sound. Without a waveform, you wouldn’t get any sound.

What’s a waveform?

To put it simple, a waveform is just a shape that’s constructed by points to make a sound. Inside synths though, they’re also oscillating.

While there are many waveforms, we’ll only be learning the 4 basic waveform shapes as most sounds are made based on these 4 waveforms.

Here’s a video of what they look like in analyzers and how they sound like :

Graphical representations of the different waveforms (played at C4) and what frequency it occupies.

Let’s talk about them in order of appearance.

First up, the sine.

A sine wave in an oscilloscope.

The sine is the purest waveform, and if you look at the video, it only occupies one frequency. It is the foundation of waveforms as all waveforms are built from it.

Unfortunately, because it only occupies one frequency, some synths don’t have it as a basic waveform. This is because it doesn’t fit the “subtractive” nature of subtractive synths since it doesn’t have anything to subtract from, and it can easily be created by low passing a triangle wave.

Speaking of triangle waves.

A triangle wave in an oscilloscope.

It sounds very similar to a sine, except that it has a bit more frequencies above it. The frequencies are made with only odd harmonics, similar to the square wave. The difference though, is that the harmonics drops off faster than that of a square wave.

I mentioned harmonics, but what are they?

To put it simple, harmonics are these things :

What the red arrows are pointing to.

Notice how there’s more sines on the higher frequencies in addition to the first sine. These are sine waves that are multiples of the fundamental sine wave (which is almost always the first one on the left). They’re what determines the timbre of a waveform.

A timbre is just the characteristics/colour of a sound. Descriptors like bright, dark, warm, harsh, dull, etc. are describing the timbre of the sound. Think of it like textures but for audio instead.

Enough about that, let’s get onto square waves.

A square wave in an oscilloscope.

As I mentioned earlier, they’re similar to a triangle wave. They’re made with only odd harmonics, but with the higher harmonics rolling off much slower than that of a triangle.

Picture for comparison. Ignore the extra things down there, they’re probably noise/artifacts from the synth I’m using.

Square waves are a bit unique, they can be controlled by something called Pulse Width Modulation. Pulse Width Modulation (or PWM) controls the spacing of the “squares”.

Here’s a sample of what it does when I gradually turn it up and down :

Notice on the bottom left how one of the “square” gets closer when it’s turned up.

Onto the next one, saw waves.

A saw wave in an oscilloscope.

Saw waves are different. They’re like square waves, but instead of just odd harmonics, it’s made with both even and odd harmonics.

There’s more of those sines in between the odd harmonics.

Saw waves are the most common waveform that’s used to make lots of sounds simply because it’s rich in harmonics.

Right now, you may be wondering which waveforms should be used for which sounds?

You can use any waveform to make any type of sound, it’s important to experiment! Though, the general usage are as follows :

Lead : Square, Saw Pad : Square, Saw Basses : Triangle, Square, Saw Sub-Bass : Sine, Triangle

Now that we’ve covered waveforms, let’s move onto envelopes.