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<h2>
<span class="refentrytitle">envlpx</span>
</h2>
<p>envlpx —
Applies an envelope consisting of 3 segments.
</p>
</div>
<div class="refsect1" title="Description">
<a id="idp19219016"></a>
<h2>Description</h2>
<p>
<span class="emphasis"><em>envlpx</em></span> -- apply an envelope consisting of 3 segments:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>stored function rise shape</p>
</li>
<li class="listitem">
<p>modified exponential pseudo steady state</p>
</li>
<li class="listitem">
<p>exponential decay</p>
</li>
</ol>
</div>
<p>
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="idp19230904"></a>
<h2>Syntax</h2>
<pre class="synopsis">ares <span class="command"><strong>envlpx</strong></span> xamp, irise, idur, idec, ifn, iatss, iatdec [, ixmod]</pre>
<pre class="synopsis">kres <span class="command"><strong>envlpx</strong></span> kamp, irise, idur, idec, ifn, iatss, iatdec [, ixmod]</pre>
</div>
<div class="refsect1" title="Initialization">
<a id="idp19232800"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>irise</em></span> -- rise time in seconds. A zero or negative value signifies no rise modification.
</p>
<p>
<span class="emphasis"><em>idur</em></span> -- overall duration in seconds. A zero or negative value will cause initialization to be skipped.
</p>
<p>
<span class="emphasis"><em>idec</em></span> -- decay time in seconds. Zero means no decay. An <span class="emphasis"><em>idec</em></span> > <span class="emphasis"><em>idur</em></span> will cause a truncated decay.
</p>
<p>
<span class="emphasis"><em>ifn</em></span> -- function table number of stored rise shape with extended guard point.
</p>
<p>
<span class="emphasis"><em>iatss</em></span> -- attenuation factor, by which the last value of the <span class="emphasis"><em>envlpx</em></span> rise is modified during the note's pseudo steady state. A factor greater than 1 causes an exponential growth and a factor less than 1 creates an exponential decay. A factor of 1 will maintain a true steady state at the last rise value. Note that this attenuation is not by fixed rate (as in a piano), but is sensitive to a note's duration. However, if <span class="emphasis"><em>iatss</em></span> is negative (or if steady state < 4 k-periods) a fixed attenuation rate of <span class="emphasis"><em>abs</em></span>(<span class="emphasis"><em>iatss</em></span>) per second will be used. 0 is illegal.
</p>
<p>
<span class="emphasis"><em>iatdec</em></span> -- attenuation factor by which the closing steady state value is reduced exponentially over the decay period. This value must be positive and is normally of the order of .01. A large or excessively small value is apt to produce a cutoff which is audible. A zero or negative value is illegal.
</p>
<p>
<span class="emphasis"><em>ixmod</em></span> (optional, between +- .9 or so) -- exponential curve modifier, influencing the steepness of the exponential trajectory during the steady state. Values less than zero will cause an accelerated growth or decay towards the target (e.g. <span class="emphasis"><em>subito piano</em></span>). Values greater than zero will cause a retarded growth or decay. The default value is zero (unmodified exponential).
</p>
</div>
<div class="refsect1" title="Performance">
<a id="idp19293688"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>kamp, xamp</em></span> -- input amplitude signal.
</p>
<p>
Rise modifications are applied for the first <span class="emphasis"><em>irise</em></span> seconds, and decay from time <span class="emphasis"><em>idur - idec</em></span>. If these periods are separated in time there will be a steady state during which <span class="emphasis"><em>amp</em></span> will be modified by the first exponential pattern. If rise and decay periods overlap then both modifications will be in effect for that time. If the overall duration <span class="emphasis"><em>idur</em></span> is exceeded in performance, the final decay will continue on in the same direction, tending asymptotically to zero.
</p>
</div>
<div class="refsect1" title="Examples">
<a id="idp19296104"></a>
<h2>Examples</h2>
<p>
Here is an example of the envlpx opcode. It uses the file <a class="ulink" href="examples/envlpx.csd" target="_top"><em class="citetitle">envlpx.csd</em></a>.
</p>
<div class="example">
<a id="idp19297000"></a>
<p class="title">
<strong>Example 206. Example of the envlpx 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>
<pre class="programlisting">
<span class="csdtag"><CsoundSynthesizer></span>
<span class="csdtag"><CsOptions></span>
<span class="comment">; Select audio/midi flags here according to platform</span>
-odac <span class="comment">;;;realtime audio out</span>
<span class="comment">;-iadc ;;;uncomment -iadc if realtime audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o envlpx.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 32
<span class="ohdr">nchnls</span> <span class="op">=</span> 2
<span class="ohdr">0dbfs</span> <span class="op">=</span> 1
<span class="oblock">instr</span> 1
irise <span class="op">=</span> 0.2
idec <span class="op">=</span> 0.5
idur <span class="op">=</span> p3 <span class="op">-</span> idec
ifn <span class="op">=</span> 1
iatss <span class="op">=</span> p5
iatdec <span class="op">=</span> 0.01
kenv <span class="opc">envlpx</span> .6, irise, idur, idec, ifn, iatss, iatdec
kcps <span class="op">=</span> <span class="opc">cpspch</span>(p4)
asig <span class="opc">vco2</span> kenv, kcps
<span class="comment">;apply envlpx to the filter cut-off frequency</span>
asig <span class="opc">moogvcf</span> asig, kcps <span class="op">+</span> (kenv <span class="op">*</span> 8 <span class="op">*</span> kcps) , .5 <span class="comment">;the higher the pitch, the higher the filter cut-off frequency</span>
<span class="opc">outs</span> asig, asig
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="comment">; a linear rising envelope</span>
<span class="stamnt">f</span> 1 0 129 -7 0 128 1
<span class="stamnt">i</span> 1 0 2 7.00 .1
<span class="stamnt">i</span> 1 + 2 7.02 1
<span class="stamnt">i</span> 1 + 2 7.03 2
<span class="stamnt">i</span> 1 + 2 7.05 3
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
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<p><br class="example-break" />
</p>
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<div class="refsect1" title="See Also">
<a id="idp19298888"></a>
<h2>See Also</h2>
<p>
<a class="link" href="envlpxr.html" title="envlpxr"><em class="citetitle">envlpxr</em></a>,
<a class="link" href="linen.html" title="linen"><em class="citetitle">linen</em></a>,
<a class="link" href="linenr.html" title="linenr"><em class="citetitle">linenr</em></a>
</p>
</div>
<div class="refsect1" title="Credits">
<a id="idp19300592"></a>
<h2>Credits</h2>
<p>Thanks goes to Luis Jure for pointing out a mistake with <span class="emphasis"><em>iatss</em></span>.</p>
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