<!-- Converted to DocBook/SGML by Kevin Conder -->
<refentry id="reverb">
  <refmeta>
    <refentrytitle>reverb</refentrytitle>
  </refmeta>
 
  <refnamediv>
    <refname>reverb</refname>
    <refpurpose>
      Reverberates an input signal with a <quote>natural room</quote> frequency response.
      <indexterm id="IndexReverb"><primary>reverb</primary></indexterm>
    </refpurpose>
  </refnamediv>
 
  <refsect1>
    <title>Description</title>
    <para>
      Reverberates an input signal with a <quote>natural room</quote> frequency response.
    </para>
  </refsect1>
 
  <refsect1>
    <title>Syntax</title>
    <synopsis>ar <command>reverb</command> asig, krvt [, iskip]</synopsis>
  </refsect1>
 
  <refsect1>
    <title>Initialization</title>
    <para>
      <emphasis>iskip</emphasis> (optional, default=0) -- initial disposition of delay-loop data space (cf. <link linkend="reson"><citetitle>reson</citetitle></link>). The default value is 0.
    </para>
  </refsect1>
 
  <refsect1>
    <title>Performance</title>
    <para>
      <emphasis>krvt</emphasis> -- the reverberation time (defined as the time in seconds for a signal to decay to 1/1000, or 60dB down from its original amplitude).
    </para>

    <para>
      A standard <emphasis>reverb</emphasis> unit is composed of four <link linkend="comb"><citetitle>comb</citetitle></link> filters in parallel followed by two <link linkend="alpass"><citetitle>alpass</citetitle></link> units in series. Loop times are set for optimal <quote>natural room response.</quote> Core storage requirements for this unit are proportional only to the sampling rate, each unit requiring approximately 3K words for every 10KC. The <link linkend="comb"><citetitle>comb</citetitle></link>, <link linkend="alpass"><citetitle>alpass</citetitle></link>, <link linkend="delay"><citetitle>delay</citetitle></link>, <link linkend="tone"><citetitle>tone</citetitle></link> and other Csound units provide the means for experimenting with alternate reverberator designs.
    </para>

    <para>
      Since output from the standard <emphasis>reverb</emphasis> will begin to appear only after 1/20 second or so of delay, and often with less than three-fourths of the original power, it is normal to output both the source and the reverberated signal. If <emphasis>krvt</emphasis> is inadvertently set to a non-positive number, <emphasis>krvt</emphasis> will be reset automatically to 0.01. (New in Csound version 4.07.) Also, since the reverberated sound will persist long after the cessation of source events, it is normal to put <emphasis>reverb</emphasis> in a separate instrument to which sound is passed via a <emphasis>global variable</emphasis>, and to leave that instrument running throughout the performance.
    </para>
  </refsect1>
 
  <refsect1>
    <title>Examples</title>
    <para>
      Here is an example of the reverb opcode. It uses the files <ulink url="examples/reverb.orc"><citetitle>reverb.orc</citetitle></ulink> and <ulink url="examples/reverb.sco"><citetitle>reverb.sco</citetitle></ulink>.

      <example>
        <title>Example of the reverb opcode.</title>

        <programlisting>
<inlinemediaobject>
            <imageobject>
              <imagedata fileref="examples/reverb.orc" format="linespecific">
            </imageobject>
          </inlinemediaobject>
        </programlisting>

        <programlisting>
<inlinemediaobject>
            <imageobject>
              <imagedata fileref="examples/reverb.sco" format="linespecific">
            </imageobject>
          </inlinemediaobject>
        </programlisting>
      </example>
    </para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <link linkend="alpass"><citetitle>alpass</citetitle></link>,
      <link linkend="comb"><citetitle>comb</citetitle></link>,
      <link linkend="valpass"><citetitle>valpass</citetitle></link>,
      <link linkend="vcomb"><citetitle>vcomb</citetitle></link>
    </para>
  </refsect1>

  <refsect1>
    <title>Credits</title>
    <para>
      <simplelist>
        <member>Author: William <quote>Pete</quote> Moss</member>
        <member>University of Texas at Austin</member>
        <member>Austin, Texas USA</member>
        <member>January 2002</member>
      </simplelist>
    </para>
  </refsect1>
</refentry>
