Mix Analog A/V Signals Together for a Cool Glitchy Effect

Live performances and music videos can benefit from cool videos in the background. One trend, for example, is to perform in front of a wall of old tube TVs. It looks especially awesome when the videos playing on those TVs are glitchy and abstract. Usually you’d just add the glitch effects to the videos beforehand, but you can also easily do it in real time if the signals are analog. That is what Michael’s Dorkwave glitch A/V mixer does, and his tutorial explains how you can make your own.

As Michael explains, “mixer” is a bit of a misnomer here, as the two video signals are hardwired together. But the way those videos mix is still very interesting, and the addition of an audio signal improves the effect. Dorkwave works with composite video, which is analog and carried on a single wire (plus ground). You can, essentially, splice two composite video wires into one, and the video feeds will be “combined.” In reality, combining them isn’t like layering one feed over the other, but instead causes them to mesh together in a way that looks very glitchy.

By patching in an audio signal at the proper level, the output video can be further affected by the frequency of the notes being played. So mixing in a guitar, for example, will cause the video to react to the guitar’s melody. Building a Dorkwave only requires simple components — mostly resistors and capacitors. The most complex component needed is a general purpose op-amp to boost an instrument level signal to a line level signal. Potentiometers are used to fine tune the volume of that signal. From there, the two video signals and the audio signal are all simply spliced together. It’s a cheap and effective way to enhance background videos for your performances.