For instance, auto-wah pedals are controlled by envelope followers. Viol Ruina What’re some other places envelope followers are used?Įnvelope followers are actually really common, but are generally built in to other devices. It makes the filter frequency follow the dynamics of the input volume, which can be expressive and interesting with the right input. Our filter, Viol Ruina, has a built-in envelope follower that you can engage with the Laser switch. Then it outputs that line as control voltage. If you drew a line that followed the edge of the plot, that would be (pretty much) the line that an envelope follower makes, because it follows the envelope.

In slightly more technical terms, the waveform (or oscillogram) plots the amplitude of the sound over time. Now, imagine drawing a line following the volume of that sound. The most famous type of envelope is the ADSR which looks like this:Īn envelope follower, however, takes an audio input and creates a control signal based on the dynamics. Envelope generators (often shortened to EGs) take a gate or trigger and create a musically useful control signal. Both generate CV, but they work quite differently. EnvelopesĪ quick distinction is in order here: don’t confuse envelope followers and envelope generators.

Envelope followers are one of those little utilities that may seem uninteresting at first glance, but they can be incredibly useful.

What is an envelope filter