How to Make a Kick Synth

One of the best ways to understand how synthesis works is to try making sounds that you might not initially expect are possible. Drum sounds are such a thing. Any synth that has an envelope which can control amplitude and pitch is suitable for creating drum sounds, if it has a white noise oscillator, it is even more powerful. This post will be the first in a series on how to make drum sounds in synthesizers, today, I will focus on the kick. For this tutorial, I am going to strip back all the interfaces of complex synthesizers, such as Serum and Massive and show you using only the controls you need.

As always, when trying to recreate a sound, we need to listen to it and hear what components it has. Drum hits tend to be short so this can be quite hard. Let's instead look at the waveform of a kick drum (above) and see what we can decipher.

The first thing we can see is that it starts off at full volume and then fades down to a silence. This is essential for us to know because we need to control the amplitude envelope, if we get this wrong, it may just sound like a long synth note.

Looking at the very first part of the waveform, the top is flat. This could be because it sustains for a few milliseconds, but I have a strong feeling that this kick sound has been compressed, pay attention to small details like this because mimicking a feature of compression might mean that when it get compressed in your mix, it may stand out even less.

Next, we can look at the pitch. As you can see in each picture, and particularly as highlighted in the one below, the pitch changes.

So we can see that the pitch sweeps from high to low. These two features are all we really need to know for making a kick synth. If we can mimic these, and get the pitches and timing right, we have a kick synth. Playing about with either of these will make the kick sound different, perhaps boomy and trap-like, or fast and clicky.

So the only thing you need to do from here is choose a root note, and then assign one envelope to modulate the amplitude, and one envelope to modulate the pitch. If the synth plugin you are using doesn't allow for envelopes to modulate pitch, you could try sweeping it from a high-harmonic saw wave, to a low-harmonic sine wave for a similar effect, alternatively, you could even experiment with a noise oscillator to mimic the high frequencies at the start, and envelope that.

If you are still stuck, there is the possibility for you to use a narrow band pass filter and use an envelope to sweep it down across the frequency range, though this will be even harder to control. Finally, FM modulation can be used on a sine wave, and envelope it for a fast sweep down. Play about with each of these different techniques, some will result in dirty lo-fi distorted kick sounds, some can make cleaner, more realistic sounds.

Below is a tutorial on building this from scratch in Reaktor, so you can see how everything works and links up internally, using the first method described.