Analog tape flanging starts with two tape machines, each with a speaker so the engineer can tell which machine is leading and which is lagging. A little finger pressure on the reel of the leading deck slows it down. When things get in sync, the sound is centered between the machines. From there, the engineer can literally pan by manipulating time - a more emotional experience than setting an oscillator - which is exactly how Dolby ATMOS works - EXCEPT that the "panning" is only to know the degree of synchronization. In the end, the two signals are mixed to mono to create the flanging effect.

While this was a failed attempt - including the camera work - you can see the determination and concentration required.

The link below is a successful example of flanging done in an earlier class.
http://www.tangible-technology.com/mu...