The Extended Karplus-Strong Algorithm
Figure 9.2 shows a block diagram of the Extended Karplus-Strong (EKS) algorithm [207].
The EKS adds the following features to the KS algorithm:

where

Note that while
can be used in the tuning allpass, it
is better to offset it to
to avoid delays
close to zero in the tuning allpass. (A zero delay is obtained by a
pole-zero cancellation on the unit circle.) First-order allpass
interpolation of delay lines was discussed in §4.1.2.
A history of the Karplus-Strong algorithm and its extensions is given
in §A.8. EKS sound
examples
are also available on the Web. Techniques for designing the
string-damping filter and/or the string-stiffness allpass
filter
are summarized below in §6.11.
An implementation of the Extended Karplus-Strong (EKS) algorithm in the Faust programming language is described (and provided) in [454].
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The Karplus-Strong Algorithm