What is chorus/vibrato? | Julianna walrus audio

the chorale cry of the siren…

With Walrus Audio's new Julianna Chorus/Vibrato pedal hitting the shelves this is an ideal time to analyse exactly how chorus effects work and expose their intimate relationship with vibrato and delay.

Chorus is multiple voices singing together in order to achieve a sound far larger and grander than any individual voice could achieve on its own.

In reference to guitar effects pedals, chorus gives the illusion that your single guitar line is in fact two guitars playing together. It achieves this by duplicating the incoming signal and sending the copy through a delay circuit with a very short delay time.

A Low Frequency Oscillator (LFO) is in control of this delay circuit, rhythmically speeding and slowing the delay time forcing the pitch of the signal to rise and fall in response.

This creates two different signals, one dry and the other with a slow vibrato permeating through it. When recombined at the output these two signals play against each other in a dreamlike way reminiscent of an angelic choir of heavenly voices.

Unlike an echo pedal, the delay times present in chorus effects are far too short to be perceived as two distinct notes separated in time. Regularly below 50ms, these are within the tolerance of our auditory system to accept the two sounds are happening at the same time, leaving only the change in pitch being noticeable.

The LFO itself can take on different periodic wave shapes to control the pitch modulation.
Julianna features sine, triangle and random arrangements.

Sine waves have smooth transitions as the curve changes direction which leads to very natural vibrato and chorus sounds.
Triangle waves on the other-hand abruptly change direction, making the chorus a little more jarring, but LFOs of this type were used in most classic and highly regarded chorus effects and vintage mojo is king for guitar tones.

Julianna is a stereo chorus/vibrato allowing players with twin amp rigs to take full advantage of wide warbles and dreamy swimming washes.
An extensive array of additional functionality including expression pedal control over speed or depth, tap tempo with note subdivisions, and a host of momentary functionality make this a powerhouse of an effect.

Watch the video at the top of this page to get a complete idea of Julianna’s sounds and features.