Ray Wilson authored this content while he was actively running MFOS as the founder and resident genius.
We retain the content because it reflects a valuable point of view representing that time and place.

Article by Ray Wilson

The MFOS Envelope Follower Filter Guitar Effect is a great first guitar effect project if you've been wanting to try building your own guitar effects. You're going to need to know how to solder, how to recognize electronic components, read schematics and most likely trouble shoot your work. You'll need to have basic tools to build a case. I have included a lot of basic information to help you succeed in building this cool effect. This would make a great starter project to do together with your son or daughter, especially if they have an interest in guitars or electronics. I strongly suggest that you look over the entire project before considering whether to build the effect, order a board or order a kit. I'm happy to answer questions related to the project via email but please read what's here first to make sure the question is not already answered. Sample MP3s envelope follower funk I.mp3 (synth clav, bass guitar and drums) envelope follower guitar.mp3 envelope follower synth baritone.mp3 (effect out, effect in) envelope follower big brass.mp3 (effect out, effect in) envelope follower clav.mp3 envelope follower drums.mp3 (effect out, effect in) envelope follower organ.mp3 (effect out, effect in) envelope follower piano.mp3 envelope follower squares.mp3 (effect out, effect in) envelope follower strings.mp3 (effect out, effect in) envelope follower wurlitzer.mp3 (effect out, effect in)

Introduction

If you like funk your going to love this effect. The main idea of an envelope follower is to create a voltage that describes the envelope of the signal being fed in. It is essentially an amplitude detector. If you could watch the input signal on an oscilloscope you would see that there are peaks and valleys in the amplitude signature. If you drew a line along the top of the signal you would be imagining what the envelope follower voltage looks like. Now we take this voltage and control a low pass filter with a nice amount of ring and put the original signal through that. The result is a great auto-wah sound with tons of character and responsiveness. Of course you can go out and buy an envelope follower at a music store, perhaps cheaper than the price of building this project. If all you want is the effect THAT is DEFINITELY the way to go. However, if you want to exercise or cultivate your electronic skills, get your soldering iron out, and feel the accomplishment of making your own very cool instrument effect then THIS is definitely the way to go.