Learn Your Modulation Effects (Flanger, Chorus, Phaser)

Learn Your Modulation Effects

The popular "Flanger, Chorus, and Phaser" effects can add subtle modulation, stereo width, and more to our signals. It's important to take advantage of all three of these effects in a mix, while still understanding how each work and the effect they will have on the sound. This will make the decision process easier in the end. 

Flanger: Flangers create a copy of the original signal and add a short delay time to it. An LFO is then applied to modulate the delay time. The copy is then mixed in with the original signal. Because the copy of the original audio signal is identical, interference via phase cancellation will occur. Resonances will be created at some frequencies, but more noticeably, a series of notches will also be created across the frequency spectrum. Since flangers have a shorter delay time, the notches will be most prominent in the high end frequency range. 

Chorus: When inserting a Chorus plugin, a copy (or several copies) of the signal are made. The copy of the signal is exactly the same as the original signal in amplitude, frequency, and phase position. The copied signal is then slightly delayed, which creates a difference in phase between the two signals. The amount of delay time is also modulated by an LFO, causing gradual changes in the frequency wavelength of the resulting signal. The resulting sound is used to imitate the effect of multiple instruments or singers, who would never be perfectly aligned with each other in the real world. 

Phaser: Once again, a copy of the original signal is made, but instead of delaying the signal, it is instead ran through an "all-pass filter." This type of filter does not affect the level of frequency content in the signal, but does introduce a phase shift around a set frequency. Phasers work by stringing several all-pass filters together to create a series of non-harmonically related notch filters. An LFO can be used to modulate these notch filters, similar to the motion in a flanger. Due to the inharmonic relationship between the phaser's notch filters, the effect sounds more gentle, producing an effect between a chorus and a flanger.