Kurzweil K2600 Musician’s Reference page 138

KDFX Reference
KDFX Algorithm Specifications
Flanger 2 is a 2 processing allocation unit (PAU) multi-sweep Thru-zero ßanger effect with two LFOs per
channel.
Noise
L Input
Figure 10-18
Flanging was originally created by summing the outputs of two un-locked tape machines while varying
their sync by pressing a hand to the outside edge of one reel, thus the historic name reel-ßanging. The key
to achieving the ßanging effect is the summing of a signal with a time-displaced replica of itself.
Adding or subtracting a signal with a time-displaced replica of itself results in a series of notches in the
frequency spectrum. These notches are equally spaced in (linear) frequency at multiples whose
wavelengths are equal to the time delay. The result is generally referred to as a comb Þlter (the name
arising from the resemblance of the spectrum to a comb). See Figure 10-18. If the levels of the signals being
added or subtracted are the same, the notches will be of inÞnite depth (in dB) and the peaks will be up 6
dB. Flanging is achieved by time-varying the delay length, thus changing the frequencies of the notches.
The shorter the delay time, the greater the notch separation. This delay time variation imparts a sense of
motion to the sound. Typically the delay times are on the order of 0-5 ms. Longer times begin to get into
10-52
High Freq
Damping
From Right To Right
Channel Channel
LFO Feedback
Static Tap Feedback
Simplified block diagram of the left channel of Flanger 2 (right channel is similar)
Dry
Delay
LFO
Tap
Levels
Static
Tap
Level
Wet
L Output
Out Gain