adsr.xml


<refentry id="adsr">
<indexterm id="IndexAdsr"><primary>adsr</primary></indexterm>
  <refentryinfo><title>Signal Generators:Envelope Generators</title></refentryinfo>
  <refmeta>
    <refentrytitle>adsr</refentrytitle>
  </refmeta>


 
  <refnamediv>
    <refname>adsr</refname>
    <refpurpose>
      Calculates the classical ADSR envelope using linear segments.
          </refpurpose>
  </refnamediv>
 
  <refsect1>
    <title>Description</title>
    <para>
      Calculates the classical ADSR envelope using linear segments.
   </para>
  </refsect1>
 
  <refsect1>
    <title>Syntax</title>
    <synopsis>ares <command>adsr</command> iatt, idec, islev, irel [, idel]</synopsis>

    <synopsis>kres <command>adsr</command> iatt, idec, islev, irel [, idel]</synopsis>
  </refsect1>
 
  <refsect1>
    <title>Initialization</title>
    <para>
      <emphasis>iatt</emphasis> -- duration of attack phase
    </para>

    <para>
      <emphasis>idec</emphasis> -- duration of decay
    </para>

    <para>
      <emphasis>islev</emphasis> -- level for sustain phase
    </para>

    <para>
      <emphasis>irel</emphasis> -- duration of release phase
    </para>

    <para>
      <emphasis>idel</emphasis> -- period of zero before the envelope starts
    </para>
  </refsect1>
 
  <refsect1>
    <title>Performance</title>
    <para>
      The envelope generated is the range 0 to 1 and may need to be scaled 
      further, depending on the amplitude required. If using 
      <link linkend="Zerodbfs"><citetitle>0dbfs</citetitle></link> = 1, scaling down
      will probably be required since playing more than one note might result in clipping.
      If not using <link linkend="Zerodbfs"><citetitle>0dbfs</citetitle></link>, scaling
       to a large amplitude (e.g. 32000) might be required.
      </para>
      <para>
      The envelope may be described as:
      <mediaobject>
        <imageobject>
          <imagedata fileref="images/adsr.png" format="PNG"/>
        </imageobject>

        <textobject>
          <phrase>Picture of an ADSR envelope.</phrase>
        </textobject>
        
        <caption>
          <para>Picture of an ADSR envelope.</para>
        </caption>
      </mediaobject>
    </para>

    <para>
       The length of the sustain is calculated from the length of the note. This means <emphasis>adsr</emphasis> is not suitable for use with MIDI events. The opcode <link linkend="madsr"><citetitle>madsr</citetitle></link> uses the <link linkend="linsegr"><citetitle>linsegr</citetitle></link> mechanism, and so can be used in MIDI applications.
    </para>

    <para>
      <emphasis>adsr</emphasis> is new in Csound version 3.49.
    </para>
  </refsect1>

  <refsect1>
    <title>Examples</title>
    <para>
      Here is an example of the adsr opcode. It uses the file <ulink url="examples/adsr.csd"><citetitle>adsr.csd</citetitle></ulink>.

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

        

        <para>See the sections <link linkend="UsingRealTime"><citetitle>Real-time Audio</citetitle></link> and <link linkend="CommandFlags"><citetitle>Command Line Flags</citetitle></link> for more information on using command line flags.</para>
          <xi:include href="examples-xml/adsr.csd.xml" xmlns:xi="http://www.w3.org/2001/XInclude"/>
      </example>
    </para>
        <para>
      Here is an example for the adsr-group, comparing the different adsr opcodes. It uses the file <ulink url="examples/adsr-group.csd"><citetitle>adsr-group.csd</citetitle></ulink>.
      <example>
        <title>Example of the adsr group.</title>
          <xi:include href="examples-xml/adsr-group.csd.xml" xmlns:xi="http://www.w3.org/2001/XInclude"/>
      </example>
    </para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <link linkend="madsr"><citetitle>madsr</citetitle></link>,
      <link linkend="mxadsr"><citetitle>mxadsr</citetitle></link>,
      <link linkend="xadsr"><citetitle>xadsr</citetitle></link>
    </para>
  </refsect1>
 
  <refsect1>
    <title>Credits</title>
    <para>Author: &namejohn;</para>
<para>New in version 3.49</para>  
  </refsect1>
</refentry>