Flanger
Description
The flanging effect can be recognized by
its characteristic pulsating sound. It is created by combining the original input
signal with a delayed copy of itself while continuously varying the delay time.
Flanger differs from chorus in two ways: the delay time for flanging is less
(between 0 and 10 ms for flanging, between 20 and 30 ms for chorus), and
flanging incorporates feedback.
Graphical Depiction
The original signal is
combined with a modified copy of itself.
The modifications are based on parameters selected by the user – the
range of delay time, oscillator type, and oscillator frequency. The output signal, multiplied by the
feedback level, is mixed with the input signal.
Effect Formula
|
y[n] = x[n] +
x[n-m] + g * y[n-m] |
|
y[n] = output
signal |
|
x[n] = input
signal |
|
sr = sampling rate
(Hz) |
|
maxDelay = maximum
delay time (sec) |
|
minDelay = minimum
delay time (sec) |
|
f = oscillator
frequency (Hz) |
|
t = time (sec) |
|
g = feedback level |
|
m = delay time in
samples |
|
m = sr *
([maxDelay-minDelay]*[1/2 sin(ft)+1/2] + minDelay) |
Source Code
(.csd files can be viewed with Notepad or any text
editor)
Example Audio Clips
|
Original unprocessed
signal |
|
|
One-voice flanger |
|
|
Two-voice flanger |
|
|
Three-voice flanger |
References
Lehman, Scott
(1996). Effects Explained. Harmony Central. Retrieved 6/04 from
http://www.harmony-central.com/Effects/effects-explained.html
Mikelson, Hans
(2000). Modeling a multieffects processor in Csound. In Boulanger,
Richard (2000), The Csound book (pp 575-594). Cambridge, MA: MIT Press.
Schindler,
Allan. (1998). Eastman Csound tutorial.
Eastman School of Music. Retrieved 6/04 from
http://www.esm.rochester.edu/onlinedocs/allan.cs/
Vercoe, Barry.
(1992). The public Csound reference manual, version 4.16. MIT
Press. Retrieved 6/04 from http://www.lakewoodsound.com/csound/hypertext/manual.htm
Zolzer, Udo.
(2002). Digital audio effects. West Sussex, England: Baffins Lane.