ifn -- table number of a stored function containing a sine wave. A large table of at least 8192 points is recommended.
iphs (optional, default=0) -- initial phase of the fundamental frequency, expressed as a fraction of a cycle (0 to 1). A negative value will cause phase initialization to be skipped. The default value is zero
xamp -- amplitude
xcps -- frequency in cycles per second
The buzz units generate an additive set of harmonically related cosine partials of fundamental frequency xcps, and whose amplitudes are scaled so their summation peak equals xamp. The selection and strength of partials is determined by the following control parameters:
knh -- total number of harmonics requested. New in Csound version 3.57, knh defaults to one. If knh is negative, the absolute value is used.
buzz and gbuzz are useful as complex sound sources in subtractive synthesis. buzz is a special case of the more general gbuzz in which klh = kr= 1; it thus produces a set of knh equal-strength harmonic partials, beginning with the fundamental. (This is a band-limited pulse train; if the partials extend to the Nyquist, i.e. knh = int (sr / 2 / fundamental freq.), the result is a real pulse train of amplitude xamp.)
Although both knh and klh may be varied during performance, their internal values are necessarily integer and may cause "pops" due to discontinuities in the output; kr, however, can be varied during performance to good effect. Both buzz and gbuzz can be amplitude- and/or frequency-modulated by either control or audio signals.
N.B. These two units have their analogs in GEN11, in which the same set of cosines can be stored in a function table for sampling by an oscillator. Although computationally more efficient, the stored pulse train has a fixed spectral content, not a time-varying one as above.
Here is an example of the buzz opcode. It uses the files buzz.orc and buzz.sco.
Example 1. Example of the buzz opcode.
/* buzz.orc */
/* Written by Kevin Conder */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
; Instrument #1.
instr 1
kamp = 20000
kcps = 440
knh = 3
ifn = 1
a1 buzz kamp, kcps, knh, ifn
out a1
endin
/* buzz.orc */
/* buzz.sco */
/* Written by Kevin Conder */
; Table #1, a sine wave.
f 1 0 16384 10 1
; Play Instrument #1 for one second.
i 1 0 1
e
/* buzz.sco */