<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>mvclpf1</title> <link rel="stylesheet" type="text/css" href="csound.css" /> <link rel="stylesheet" type="text/css" href="syntax-highlighting.css" /> <meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /> <link rel="home" href="index.html" title="The Canonical Csound Reference Manual" /> <link rel="up" href="OpcodesTop.html" title="Orchestra Opcodes and Operators" /> <link rel="prev" href="mvchpf.html" title="mvchpf" /> <link rel="next" href="mvclpf2.html" title="mvclpf2" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">mvclpf1</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="mvchpf.html">Prev</a> </td> <th width="60%" align="center">Orchestra Opcodes and Operators</th> <td width="20%" align="right"> <a accesskey="n" href="mvclpf2.html">Next</a></td> </tr> </table> <hr /> </div> <div class="refentry"> <a id="mvclpf1"></a> <div class="titlepage"></div> <a id="IndexMvclpf1" class="indexterm"></a> <div class="refnamediv"> <h2> <span class="refentrytitle">mvclpf1</span> </h2> <p>mvclpf1 — Moog voltage-controlled lowpass filter emulation. </p> </div> <div class="refsect1"> <a id="idm281472911682136"></a> <h2>Description</h2> <p> Mvclpf1 is an digital implementation of the 4th-order (24 dB/oct) Moog ladder filter originally written by Fons Andriaensen. According to the author, mvclpf1 "is a fairly simple design, and it does not even pretend to come close the 'real thing'. It uses a very crude approximation of the non-linear resistor in the first filter section only. [...] [I]t's [a] cheap (in terms of CPU usage) general purpose 24 dB/oct lowpass filter that could be useful". </p> </div> <div class="refsect1"> <a id="idm281472911680472"></a> <h2>Syntax</h2> <pre class="synopsis">asig <span class="command"><strong>mvclpf1</strong></span> ain, xcf, xres[,istor]</pre> </div> <div class="refsect1"> <a id="idm281472911617448"></a> <h2>Initialization</h2> <p> <span class="emphasis"><em>istor</em></span> --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. </p> </div> <div class="refsect1"> <a id="idm281472911615544"></a> <h2>Performance</h2> <p> <span class="emphasis"><em>ain</em></span> -- input signal. </p> <p> <span class="emphasis"><em>xcf</em></span> -- filter cutoff frequency. The useful range is around six octaves below and above middle C (pch 8.00). </p> <p> <span class="emphasis"><em>xres</em></span> -- resonance, limited to the interval [0,1]. </p> </div> <div class="refsect1"> <a id="idm281472911612152"></a> <h2>Examples</h2> <p> Here is an example of the mvclpf1 opcode. It uses the file <a class="ulink" href="examples/mvclpf1.csd" target="_top"><em class="citetitle">mvclpf1.csd</em></a>. </p> <div class="example"> <a id="idm281472911610296"></a> <p class="title"> <strong>Example 589. Example of the mvclpf1 opcode.</strong> </p> <div class="example-contents"> <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p> <div class="refsect1"> <a id="idm281472735019096"></a> <pre class="programlisting"> <span class="nt"><CsoundSynthesizer></span> <span class="nt"><CsOptions></span> -odac <span class="nt"></CsOptions></span> <span class="nt"><CsInstruments></span> <span class="vg">0dbfs</span> <span class="o">=</span> <span class="mi">1</span> <span class="kd">instr</span> <span class="nf">1</span> k<span class="n">env</span> <span class="nb">linen</span> <span class="nb">p4</span><span class="p">,</span><span class="mf">0.1</span><span class="p">,</span><span class="nb">p3</span><span class="p">,</span><span class="mf">0.1</span> a<span class="n">in</span> <span class="nb">rand</span> k<span class="n">env</span> k<span class="n">fr</span> <span class="nb">expon</span> <span class="mi">220</span><span class="p">,</span> <span class="nb">p3</span><span class="p">,</span> <span class="mi">1760</span> a<span class="n">sig</span> <span class="nb">mvclpf1</span> a<span class="n">in</span><span class="p">,</span>k<span class="n">fr</span><span class="p">,</span><span class="mf">0.9</span> <span class="nb">out</span> a<span class="n">sig</span> <span class="kd">endin</span> <span class="nt"></CsInstruments></span> <span class="nt"><CsScore></span> <span class="nb">i</span><span class="mi">1</span> <span class="mi">0</span> <span class="mi">5</span> <span class="mf">0.9</span> <span class="nt"></CsScore></span> <span class="nt"></CsoundSynthesizer></span> </pre> </div> </div> </div> <p><br class="example-break" /> </p> </div> <div class="refsect1"> <a id="idm281472911606104"></a> <h2>Credits</h2> <p> </p> <table border="0" summary="Simple list" class="simplelist"> <tr> <td>Author: Fons Andriaensen, </td> </tr> <tr> <td> ported to Csound by Victor Lazzarini</td> </tr> <tr> <td>January 2016</td> </tr> </table> <p> </p> <p>New in version 6.07</p> <p>January 2016.</p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="mvchpf.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="OpcodesTop.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="mvclpf2.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">mvchpf </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> mvclpf2</td> </tr> </table> </div> </body> </html>