Chorus / Flange

Chorus adds depth, richness and harmonic structure to a sound by mimicking the effect of two or more sounds playing at the same time.

When the effect is produced successfully the sound has a rich, shimmering quality which would be absent if the sound came from a single source. The effect is more apparent when listening to sounds which sustain for longer periods of time.

Clap with flange effect

The chorus effect processor works by delaying the input signal by about 15 milliseconds and mixing it back into the original signal. The delayed signal is then slightly detuned in pitch from the other which is controlled via the modulation rate and depth controls. A low modulation rate and depth adds a subtle change comparable to an ensemble. Add more depth (pitch shifting) and the chorus becomes more aggressive creating a warbling sound. Chorus is most effective in thickening pad parts or string ensemble sounds but is also effective on vocals and guitars.

Flanging is similar to chorus in that it occurs when two identical signals are mixed together. One signal is time-delayed by a small and gradually changing amount.

The modulation produces a swept 'comb filter' effect; peaks and notches are produced in the resultant frequency spectrum, related to each other in a linear harmonic series. Varying the time delay causes these to sweep up and down the frequency spectrum. Part of the output signal is usually fed back to the input (a 're-circulating delay line'), producing a resonance effect which further enhances the intensity of the peaks and troughs. Flanging works best on harmonically rich sounds such as bright string pads, although it can also be used on drums and cymbals.

Common Controls Summary

Delay – The delay control determines the delay time used to create the chorus/flanger effect. Usually, flanger-type effects use short delay times while chorus-type effects use medium to long delays.

Feedback – The feedback control determines the amount of effect signal fed back to the input, which in turn affects the intensity and character of the effect. Turning it extreme left or right produces different flanger effects with a distinct resonance, while keeping it centred produces a more gentle chorus effect.

LFO Rate - The LFO Rate determines the frequency of the LFO modulating the delay time. The higher the value, the faster the sound will oscillate.

LFO Sync - The LFO sync control allows for the LFO to be synchronised to the songs tempo, in one of 16 possible time divisions.

LFO Freq. Mod - The LFO Freq. Mod control determines the depth of the LFO modulation, i.e. by how much the frequency parameter should be modulated. At zero the effect is static