Description

A first-order recursive low-pass filter with variable frequency response.

Syntax

kres tonek ksig, khp [, iskip]

Initialization

iskip (optional, default=0) -- initial disposition of internal data space. Since filtering incorporates a feedback loop of previous output, the initial status of the storage space used is significant. A zero value will clear the space; a non-zero value will allow previous information to remain. The default value is 0.

Performance

kres -- the output signal at control-rate.

ksig -- the input signal at control-rate.

khp -- the response curve's half-power point, in Hertz. Half power is defined as peak power / root 2.

tonek is like tone except its output is at control-rate rather than audio rate.

Examples

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

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

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

gisin ftgen 0, 0, 2^10, 10, 1

instr 1

ksig	randomh	400, 1800, 150
aout	poscil	.2, 100+ksig, gisin
	outs	aout, aout
endin

instr 2

ksig	randomh	400, 1800, 150
khp	line	1, p3, 100	;vary high-pass
ksig	tonek	ksig, khp
aout	poscil	.2, 100+ksig, gisin
	outs	aout, aout
endin

</CsInstruments>
<CsScore>

i 1 0 5
i 2 5.5 5
e
</CsScore>
</CsoundSynthesizer>

See Also

areson, aresonk, atone, atonek, port, portk, reson, resonk, tone

Credits