Double vibrocated sploshing flange

Ken’s Flanger

Flanging is an unusual name for an audio effect, and its certainly not a common word in music or signal processing. The flange refers to a rim or edge, especially on a tape reel. Producers were known to manipulate the flange of a tape reel to achieve nice effects on many early tape recordings. One of the earliest known examples of producing a sound similar to the modern flanger is ‘The Big Hurt’ by Tony Fisher, recorded in 1959.

But the origin of the name of the audio effect is an unusual one, and has been well documented by Beatles historians Bill Biersach and Mark Lewisohn.

In 1966, the Beatles recorded Revolver at Abbey Road. The studio technician Ken Townsend later said that “they would relate what sounds they wanted and we then had to go away and come back with a solution… they often liked to double-track their vocals, but it’s quite a laborious process and they soon got fed up with it. So, after one particularly trying night-time session doing just that, I was driving home and suddenly had an idea.”

What Townsend devised was not the modern flanging, but the closely related chorus effect, or artificial double tracking (ADT). But its implemented using the same approach, slowing down and speeding up a tape machine. The seemingly random variations in speed (and hence also pitch) mimic the effect of a singer trying to harmonise with the original.

John Lennon loved the effect, and asked George Martin, the Beatles producer, to explain it. As Martin recalled, “I knew he’d never understand it, so I said, ‘Now listen, it’s very simple. We take the original image and split it through a double vibrocated sploshing flange with double negative feedback …’ He said, ‘You’re pulling my leg, aren’t you?’ I replied, ‘Well, let’s flange it again and see.’ From that moment on, whenever he wanted it he’d ask for his voice to be ‘flanged,’ or call out for ‘Ken’s flanger.’ ”


  • M. Lewisohn, The Beatles Recording Sessions. New York: Harmony Books (Crown Publishers), 1989.
  • G. Martin and W. Pearson, Summer of Love: The Making of Sgt Pepper. London: Pan Books, 1994.