Extended Karplus-Strong Algorithm

The Extended Karplus-Strong (EKS) algorithm [4]
extends the KS digitar in a number of ways that will be introduced
one-by-one and then brought together in the complete program
listing shown in Figures 9 and 10. The EKS extensions were motivated by the demands of a musical
composition^{7}and the interpretation of the KS algorithm as a transfer-function
model of a simplified physical string [11, pp. 158-198].
They illustrate how several small digital filters can achieve various
desired musical effects. We will see that the EKS can be regarded as
a *blend* of spectral and physical (transfer-function) modeling
techniques.

Figure 4 illustrates where the various filters may be located in the patch. The filters in series outside the feedback loop can of course be implemented in any order, and the filters within the feedback loop can be arbitrarily reordered. (The series order of linear, time-invariant filters may matter in fixed-point, but generally not in floating-point.)

- Pick-Direction Lowpass Filter
- Pick-Position Comb Filter
- One-Zero String Damping Filter
- Two-Zero String Damping Filter

- Dynamic Level Lowpass Filter

- Tuning the EKS String

- EKS Tuning and Decay Exercises
- EKS Faust Listing
- MIDI Control of an EKS Patch in PD
- Generality of the EKS Algorithm

Download faust_strings.pdf

REALSIMPLE Project — work supported in part by the Wallenberg Global Learning Network .

Released

Center for Computer Research in Music and Acoustics (CCRMA), Stanford University