The FlangerHand plug-in is based on
the idea of the early flanging effect realised on a
setup of up to 4 tape machines (1 source, 3
recorders) in the '60s. The playback-head output
from two recorders was mixed together onto a third
recorder. The "flange" effect originated when an
engineer would literally put a finger on the flange,
or rim of one of the tape reels so that the machine
was slowed down, slipping out of sync by tiny
degrees. A listener would hear a "drainpipe"
sweeping effect as shifting sum-and-difference
harmonics were created. When the operator removed
his finger the tape sped up again, making the effect
sweep back in the other direction.