lorisfrqenvelope

lorisfrqenvelope — Create a variable length breakpoint-style frequency envelope which scales frequencies.

Syntax

lorisfrqenvelope  isrcidx, istoreidx, kcurve, kfrq1, kscalar1 ... kfrqN, kscalarN

Description

If a frequency from a Loris analysis is equal to breakpoint kfrqN, it will be multiplied by kscalarN. If a frequency falls between two breakpoints, kfrqN and kfrqN+1 then it will be multiplied by a value between kscalarN and kscalarN+1 interpolated according to kcurve. Breakpoint frequencies (kfrq1, kfrq2, ...) must be ordered from lowest to highest.

Initialization

isrcidx is an integer label that identifies the stored set of SDIF partials that are used. Use lorisread to import partials from an SDIF file, store them in memory and assign a label.

itgtidx is an integer label where the partial data created by this opcode will be stored. This label may be subsequently used with any other loris opcode for further transformation or resynthesis with lorisplay. if itgtidx and isrcidx are identical then isrcidx is overwritten.

Performance

kfrqN is the frequency value which defines the location of the Nth breakpoint scalar.

kscalarN is the scalar value which is applied to frequencies at frequency kfrqN.

kcurve is the slope of the interpolation between neighboring breakpoints. 1 yields a linear interpolation; 2 is an exponential interpolation and 0.5 is a logarithmic. In general kcurve gets steeper above 1 and more rounded below 1. kcurve must be great than 0.

Credits

The Loris unit generators were written by Kelly Fitz (loris@cerlsoundgroup.org). It is patterned after a prototype implementation of the lorisplay unit generator written by Corbin Champion, and based on the method of Bandwidth-Enhanced Additive Synthesis and on the sound morphing algorithms implemented in the Loris library for sound modeling and manipulation. The opcodes were further adapted as a plugin for Csound 5 by Michael Gogins. Ben Hackbarth (hackbarth@ucsd.edu) wrote the Extended Loris Opcodes.