buzz

Output is a set of harmonically related sine partials.

Syntax

ares buzz xamp, xcps, knh, ifn [, iphs]

Initialization

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

Performance

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 = kmul = 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 knh may be varied during performance, its internal value is necessarily integer and may cause “pops” due to discontinuities in the output. buzz can be amplitude- and/or frequency-modulated by either control or audio signals.

N.B. This unit has its analog 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.

Examples

Here is an example of the buzz opcode. It uses the file buzz.csd.

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac     ;;;RT audio out
;-iadc    ;;;uncomment -iadc if RT audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o buzz.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs = 1

instr 1

kcps = 110
ifn  = 1

knh  line p4, p3, p5
asig buzz 1, kcps, knh, ifn
     outs asig, asig
endin

</CsInstruments>
<CsScore>

;sine wave.
f 1 0 16384 10 1

i 1 0 3 20 20
i 1 + 3 3 3
i 1 + 3 10 1
e

</CsScore>
</CsoundSynthesizer>

A musical example featuring the buzz opcode: BuzzFof_Cucchi.csd by Stefano Cucchi.

See Also

Dynamic Spectrum Oscillators

Credits

September 2003. Thanks to Kanata Motohashi for correcting the mentions of the kmul parameter.