Modulating a Single Band Filter

Creating Crazy Effects using a Modulator to process a Single Filter Band.


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Filter modulation opens up the world to us sound designers who like to create custom sounds for our mix projects. It is a process that has been in existence since the first decent analogue synthesizers were built but it has always been a step away from reaching producers as a mix colouring tool. That has now changed and more and more producers are realising the power that filter modulation provides in mixing tasks.

To understand how to modulate any parameter of a filter unit one must bite the bullet and swallow some theory and background information on what filters are and how they work.


I have explained what filters are and how they work extensively in Filters and Filtering  However, if you’re more in the mood to take the visual approach why not have a look at this video which runs through all the areas you will need to know to master a filter like a pro.

What is a Modulator

A modulator is a device that controls the parameters of another device. The modulator is called the source and the device being modulated is called the destination. A good and simple example of a source modulator is the pitch wheel on a keyboard and in this instance the destination is pitch. In other words, the pitch wheel when moved alters the pitch of the sound being played.

Almost anything can be a source modulator. Most synthesizer keyboards have a dedicated modwheel (modulation wheel) which can be assigned to a whole host of destination sources and we can replicate this scenario in our DAWs. In fact, we can design our own modulators and have them trigger all manner of processes. We can use Midi controllers to control any desired destination and now we can even use audio to modulate another piece of audio. And it doesn’t end there. Most DAWs give you extensive source modulators to use in the Automation Lanes. In effect, we can use a shape to control the volume of audio.

Modulator Source and Destination

Now that we know what a filter is and how it works we can start to use modulators to control the various features of the filter unit. Common source modulators are LFOs and step sequencers. Common modulator destinations are filter cut-off and resonance. BUT that is only touching the tip of the iceberg. We can use advanced source/destinations to create some crazy textures abut that is dependent on what features the filter unit possesses and whether you want to use additional modulator sources via your DAW’s tools like lane automation.

Premium Video Tutorial

To discover how to use filter modulation to create wonderful new textures you can purchase a 6 minute video for just £1

In the video I use Soundtoys Filter Freak which is a glorified filter unit with acres of control. I explain all the workings of this wonderful plugin and show you how to use the various sources available to modulate the plethora of destinations afforded by this plugin. I cover all the usual filter cut-off modulation tricks, filter resonance modulation madness, step based rhythmic modulation and so on. Every step of every process is explained in detail and using audio examples.

Topics covered in this video are:

  • What is a Filter
  • What is Modulation
  • Modes and Types
  • Understanding Q and Width
  • Creative uses
  • Tips and Tricks