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# rezzy

rezzy -- A resonant low-pass filter.

## Description

A resonant low-pass filter.

## Syntax

ar rezzy asig, xfco, xres [, imode]

## Initialization

imode (optional, default=0) -- high-pass or low-pass mode. If zero, rezzy is low-pass. If not zero, rezzy is high-pass. Default value is 0. (New in Csound version 3.50)

## Performance

asig -- input signal

xfco -- filter cut-off frequency in Hz. As of version 3.50, may i-,k-, or a-rate.

xres -- amount of resonance. Values of 1 to 100 are typical. Resonance should be one or greater. As of version 3.50, may a-rate, i-rate, or k-rate.

rezzy is a resonant low-pass filter created empirically by Hans Mikelson.

## Examples

Here is an example of the rezzy opcode. It uses the files rezzy.orc and rezzy.sco.

Example 1. Example of the rezzy opcode.

    /* rezzy.orc */
    ; Initialize the global variables.
    sr = 44100
    kr = 4410
    ksmps = 10
    nchnls = 1

    ; Instrument #1.
    instr 1
      ; Use a nice sawtooth waveform.
      asig vco 32000, 220, 1

      ; Vary the filter-cutoff frequency from .2 to 2 KHz.
      kfco line 200, p3, 2000

      ; Set the resonance amount.
      kres init 25

      a1 rezzy asig, kfco, kres

      out a1
    endin
    /* rezzy.orc */

    /* rezzy.sco */
    ; Table #1, a sine wave for the vco opcode.
    f 1 0 16384 10 1

    ; Play Instrument #1 for three seconds.
    i 1 0 3
    e
    /* rezzy.sco */

## See Also

biquad, moogvcf

## Credits

Author: Hans Mikelson
October 1998

Example written by Kevin Conder.

New in Csound version 3.49

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