The flanging effect is an audio effect which combines two audio signals. Because the second signal is somewhat delayed, a swirling effect results. The electronic flanging effect comes from a natural acoustic phenomenon that occurs when listeners perceive a wide-band noise due to a combination of a direct and a delayed sound.
The Discovery of the Phenomenon
The flanging phenomenon discovery dates back to 1693. In contrast, the flanging effect was first heard of around 1969. The first time musicians used this as a sound effect was inside a recording studio around 1945. About a decade later, producers started using it with analog tape recorders and mixing consoles.
Flanging Effect’s First Steps
Engineers fed tape recorders an identical signal and controlled it. They combined the tape output while adding pressure on the flange of one of the reels, causing it to slow down. It was essential to use two recorders in order to synch the overall delay. The delay was established by monitoring the playback head of the flanging recorder. Keep in mind that the exact delay depends on both the arrangement of the record and the playback heads.
Types of Flanging Effect
It’s possible for electronic flanging to achieve the mentioned effect when using a continuous varying delay line. The delay line of an electronic flanger is varied by a low-frequency oscillator that releases a sine or triangle shape which works within a 1 to 20Hz range. Experts also see flanging as a swept comb filter effect.
When both the amplitude of the original signal and the delay version are equivalent, the depth of flanging achieves a maximum level. Its structure is equal to a feedforward or the FIR comb filter with a time-varying delay. By using this audio effect, the user can shift between positive and negative feedback to determine which sound should be flanged.
The Barber Pole, also known as infinite flanging, is another type of this effect. It uses multiple delay lines that fade in and out of the mix as they sweep to the delay time limit. Many hardware and software effect systems include it.
