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<h2>
<span class="refentrytitle">clear</span>
</h2>
<p>clear —
Zeroes a list of audio signals.
</p>
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<div class="refsect1">
<a id="idm281472946591176"></a>
<h2>Description</h2>
<p>
<span class="emphasis"><em>clear</em></span> zeroes a list of audio signals.
</p>
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<div class="refsect1">
<a id="idm281472946587544"></a>
<h2>Syntax</h2>
<pre class="synopsis"><span class="command"><strong>clear</strong></span> avar1 [, avar2] [, avar3] [...]</pre>
</div>
<div class="refsect1">
<a id="idm281472946585480"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>avar1, avar2, avar3,</em></span> ... -- signals to be zeroed
</p>
<p>
<span class="emphasis"><em>clear</em></span> sets every sample of each of the given audio signals to zero when it is performed. This is equivalent to writing <span class="emphasis"><em>avarN = 0</em></span> in the orchestra for each of the specified variables. Typically, <span class="emphasis"><em>clear</em></span> is used with global variables that combine multiple signals from different sources and change with each k-pass (performance loop) through all of the active instrument instances. After the final usage of such a variable and before the next k-pass, it is necessary to clear the variable so that it does not add the next cycle's signals to the previous result. <span class="emphasis"><em>clear</em></span> is especially useful in combination with <a class="link" href="vincr.html" title="vincr"><em class="citetitle">vincr</em></a> (variable increment) and they are intended to be used together with file output opcodes such as <a class="link" href="fout.html" title="fout"><em class="citetitle">fout</em></a>.
</p>
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<div class="refsect1">
<a id="idm281472946517208"></a>
<h2>Examples</h2>
<p>
Here is an example of the clear opcode. It uses the file <a class="ulink" href="examples/clear.csd" target="_top"><em class="citetitle">clear.csd</em></a>.
</p>
<div class="example">
<a id="idm281472946515352"></a>
<p class="title">
<strong>Example 129. Example of the clear opcode.</strong>
</p>
<div class="example-contents">
<div class="refsect1">
<a id="idm281472780809736"></a>
<pre class="programlisting">
<span class="nt"><CsoundSynthesizer></span>
<span class="nt"><CsOptions></span>
<span class="c1">; Select audio/midi flags here according to platform</span>
-odac <span class="c1">;;;realtime audio out</span>
<span class="c1">;-iadc ;;;uncomment -iadc if RT audio input is needed too</span>
<span class="c1">; For Non-realtime ouput leave only the line below:</span>
<span class="c1">; -o clear.wav -W ;;; for file output any platform</span>
<span class="nt"></CsOptions></span>
<span class="nt"><CsInstruments></span>
<span class="vg">sr</span> <span class="o">=</span> <span class="mi">44100</span>
<span class="vg">ksmps</span> <span class="o">=</span> <span class="mi">32</span>
<span class="vg">nchnls</span> <span class="o">=</span> <span class="mi">2</span>
<span class="vg">0dbfs</span> <span class="o">=</span> <span class="mi">1</span>
ga<span class="n">Reverb</span> <span class="nb">init</span> <span class="mi">0</span>
<span class="kd">instr</span> <span class="nf">1</span>
i<span class="n">dur</span> <span class="o">=</span> <span class="nb">p3</span>
k<span class="n">pitch</span> <span class="o">=</span> <span class="nb">p4</span>
a<span class="n">1</span> <span class="nb">diskin2</span> <span class="s">"fox.wav"</span><span class="p">,</span> k<span class="n">pitch</span>
a<span class="n">1</span> <span class="o">=</span> a<span class="n">1</span><span class="o">*</span><span class="mf">.5</span> <span class="c1">;reduce volume</span>
<span class="nb">vincr</span> ga<span class="n">Reverb</span><span class="p">,</span> a<span class="n">1</span>
<span class="kd">endin</span>
<span class="kd">instr</span> <span class="nf">99</span> <span class="c1">; global reverb </span>
a<span class="n">l</span><span class="p">,</span> a<span class="n">r</span> <span class="nb">reverbsc</span> ga<span class="n">Reverb</span><span class="p">,</span> ga<span class="n">Reverb</span><span class="p">,</span> <span class="mf">.8</span><span class="p">,</span> <span class="mi">10000</span>
<span class="nb">outs</span> ga<span class="n">Reverb</span><span class="o">+</span>a<span class="n">l</span><span class="p">,</span> ga<span class="n">Reverb</span><span class="o">+</span>a<span class="n">r</span>
<span class="nb">clear</span> ga<span class="n">Reverb</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">3</span> <span class="mi">1</span>
<span class="nb">i</span><span class="mi">99</span> <span class="mi">0</span> <span class="mi">5</span>
<span class="nb">e</span>
<span class="nt"></CsScore></span>
<span class="nt"></CsoundSynthesizer></span>
</pre>
</div>
</div>
</div>
<p><br class="example-break" />
</p>
<p>
See the <a class="link" href="fout.html" title="fout"><em class="citetitle">fout</em></a> opcode for another example.
</p>
</div>
<div class="refsect1">
<a id="idm281472946512200"></a>
<h2>See Also</h2>
<p>
<a class="link" href="vincr.html" title="vincr"><em class="citetitle">vincr</em></a>
</p>
</div>
<div class="refsect1">
<a id="idm281472946510088"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Gabriel Maldonado</td>
</tr>
<tr>
<td>Italy</td>
</tr>
<tr>
<td>1999</td>
</tr>
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<p>
</p>
<p>New in Csound version 3.56</p>
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