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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">
<a id="idm281472939726232"></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">
<a id="idm281472939655784"></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">
<a id="idm281472939652040"></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">
<a id="idm281472939639480"></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 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">
<a id="idm281472939634184"></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="idm281472939632408"></a>
<p class="title">
<strong>Example 242. 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>
<div class="refsect1">
<a id="idm281472771928648"></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 realtime audio input is needed too</span>
<span class="c1">; For Non-realtime ouput leave only the line below:</span>
<span class="c1">; -o envlpx.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>
<span class="kd">instr</span> <span class="nf">1</span>
i<span class="n">rise</span> <span class="o">=</span> <span class="mf">0.2</span>
i<span class="n">dec</span> <span class="o">=</span> <span class="mf">0.5</span>
i<span class="n">dur</span> <span class="o">=</span> <span class="nb">p3</span> <span class="o">-</span> i<span class="n">dec</span>
i<span class="n">fn</span> <span class="o">=</span> <span class="mi">1</span>
i<span class="n">atss</span> <span class="o">=</span> <span class="nb">p5</span>
i<span class="n">atdec</span> <span class="o">=</span> <span class="mf">0.01</span>
k<span class="n">env</span> <span class="nb">envlpx</span> <span class="mf">.6</span><span class="p">,</span> i<span class="n">rise</span><span class="p">,</span> i<span class="n">dur</span><span class="p">,</span> i<span class="n">dec</span><span class="p">,</span> i<span class="n">fn</span><span class="p">,</span> i<span class="n">atss</span><span class="p">,</span> i<span class="n">atdec</span>
k<span class="n">cps</span> <span class="o">=</span> <span class="nb">cpspch</span><span class="p">(</span><span class="nb">p4</span><span class="p">)</span>
a<span class="n">sig</span> <span class="nb">vco2</span> k<span class="n">env</span><span class="p">,</span> k<span class="n">cps</span>
<span class="c1">;apply envlpx to the filter cut-off frequency</span>
a<span class="n">sig</span> <span class="nb">moogvcf</span> a<span class="n">sig</span><span class="p">,</span> k<span class="n">cps</span> <span class="o">+</span> <span class="p">(</span>k<span class="n">env</span> <span class="o">*</span> <span class="mi">8</span> <span class="o">*</span> k<span class="n">cps</span><span class="p">)</span> <span class="p">,</span> <span class="mf">.5</span> <span class="c1">;the higher the pitch, the higher the filter cut-off frequency</span>
<span class="nb">outs</span> a<span class="n">sig</span><span class="p">,</span> a<span class="n">sig</span>
<span class="kd">endin</span>
<span class="nt"></CsInstruments></span>
<span class="nt"><CsScore></span>
<span class="c1">; a linear rising envelope</span>
<span class="nb">f</span> <span class="mi">1</span> <span class="mi">0</span> <span class="mi">129</span> <span class="o">-</span><span class="mi">7</span> <span class="mi">0</span> <span class="mi">128</span> <span class="mi">1</span>
<span class="nb">i</span> <span class="mi">1</span> <span class="mi">0</span> <span class="mi">2</span> <span class="mf">7.00</span> <span class="mf">.1</span>
<span class="nb">i</span> <span class="mi">1</span> <span class="o">+</span> <span class="mi">2</span> <span class="mf">7.02</span> <span class="mi">1</span>
<span class="nb">i</span> <span class="mi">1</span> <span class="o">+</span> <span class="mi">2</span> <span class="mf">7.03</span> <span class="mi">2</span>
<span class="nb">i</span> <span class="mi">1</span> <span class="o">+</span> <span class="mi">2</span> <span class="mf">7.05</span> <span class="mi">3</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>
</div>
<div class="refsect1">
<a id="idm281472939628280"></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">
<a id="idm281472939624248"></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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