Flanger Effect - what is it and how does it work

A flanger is another modulation effect whereby the delayed signal, which is added back to an equal amount of the dry signal, is modulated by using a LFO. If you add the output back into the input (feedback) you get resonance with the comb-filter effect.

Comb-filtering occurs when the delayed signal is combined with the dry direct signal. The comb filter creates peaks and troughs in the frequency response.

If the polarity of the dry signal is the same as the delayed signal we call this positive flanging and if the polarity of the delayed signal is opposite to the polarity of the dry signal we call this negative flanging. If the feedback is greater then you get what we call resonant flanging. The more feedback applied the more resonant the effect. This is a bit like increasing the resonance on a normal filter. Feedback also has phase. If the feedback is in phase then it is called positive phase. If the feedback is out of phase it is called negative feedback. Negative feedback has odd harmonics whereas positive feedback has even harmonics.

Some flangers will have a phase parameter to control the negative and positive phase and this has quite a dramatic effect on the overall effect. Additionally, the phase controls can also alter the degree rates and therefore have a dramatic impact on the way the effect is output.

Possibly one of the most underrated of all studio effects the Flanger is a very versatile effect offering huge sound design scope. Let me run through this effect for you.