<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>harmon2</title>
<link rel="stylesheet" href="csound.css" type="text/css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2" />
<link rel="home" href="index.html" title="The Canonical Csound Reference Manual" />
<link rel="up" href="OpcodesTop.html" title="Orchestra Opcodes and Operators" />
<link rel="prev" href="harmon.html" title="harmon" />
<link rel="next" href="hilbert.html" title="hilbert" />
</head>
<body>
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">harmon2</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="harmon.html">Prev</a> </td>
<th width="60%" align="center">Orchestra Opcodes and Operators</th>
<td width="20%" align="right"> <a accesskey="n" href="hilbert.html">Next</a></td>
</tr>
</table>
<hr />
</div>
<div class="refentry" title="harmon2">
<a id="harmon2"></a>
<div class="titlepage"></div>
<a id="IndexHarmon2" class="indexterm"></a>
<div class="refnamediv">
<h2>
<span class="refentrytitle">harmon2</span>
</h2>
<p>harmon2 —
Analyze an audio input and generate harmonizing voices in
synchrony with formants preserved.
</p>
</div>
<div class="refsect1" title="Description">
<a id="id2937410"></a>
<h2>Description</h2>
<p>
Generate harmonizing voices with formants preserved.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="id2937421"></a>
<h2>Syntax</h2>
<pre class="synopsis">ares <span class="command"><strong>harmon2</strong></span> asig, koct, kfrq1, kfrq2, icpsmode, ilowest[, ipolarity]</pre>
<pre class="synopsis">ares <span class="command"><strong>harmon3</strong></span> asig, koct, kfrq1, \
kfrq2, kfrq3, icpsmode, ilowest[, ipolarity]</pre>
<pre class="synopsis">ares <span class="command"><strong>harmon4</strong></span> asig, koct, kfrq1, \
kfrq2, kfrq3, kfrq4, icpsmode, ilowest[, ipolarity]</pre>
</div>
<div class="refsect1" title="Initialization">
<a id="id2937665"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>icpsmode</em></span> -- interpreting mode for the
generating frequency inputs <span class="emphasis"><em>kfrq1</em></span>, <span class="emphasis"><em>kfrq2</em></span>, <span class="emphasis"><em>kfrq3</em></span> and <span class="emphasis"><em>kfrq4</em></span>:
0: input values are ratios w.r.t. the cps equivalent of <span class="emphasis"><em>koct</em></span>.
1: input values are the actual requested frequencies in cps.
</p>
<p>
<span class="emphasis"><em>ilowest</em></span> -- lowest value of the <span class="emphasis"><em>koct</em></span> input for which harmonizing voices will be generated.
</p>
<p>
<span class="emphasis"><em>ipolarity</em></span> -- polarity of <span class="emphasis"><em>asig</em></span> input, 1 = positive glottal pulses, 0 = negative. Default is 1.
</p>
</div>
<div class="refsect1" title="Performance">
<a id="id2938338"></a>
<h2>Performance</h2>
<p>
<span class="command"><strong>Harmon2</strong></span>, <span class="command"><strong>harmon3</strong></span>
and <span class="command"><strong>harmon4</strong></span> are high-performance harmonizers,
able to provide up to four pitch-shifted copies of the input
<span class="emphasis"><em>asig</em></span> with spectral formants preserved. The
pitch-shifting algorithm requires an accurate running estimate
(<span class="emphasis"><em>koct</em></span>, in decimal oct units) of the pitched
content of <span class="emphasis"><em>asig</em></span>, normally gained from an
independent pitch tracker such as <span class="emphasis"><em>specptrk</em></span>.
The algorithm then isolates the most recent full pulse
within <span class="emphasis"><em>asig</em></span>, and uses this to generate the
other voices at their required pulse rates.
</p>
<p>
If the frequency (or ratio) presented
to <span class="emphasis"><em>kfrq1</em></span>, <span class="emphasis"><em>kfrq2</em></span>, <span class="emphasis"><em>kfrq3</em></span>
or <span class="emphasis"><em>kfrq4</em></span> is zero, then no signal is
generated for that voice. If any of them is non-zero, but
the <span class="emphasis"><em>koct</em></span> input is below the
value <span class="emphasis"><em>ilowest</em></span>, then that voice will output
a direct copy of the input <span class="emphasis"><em>asig.</em></span> As a
consequence, the data arriving at the k-rate inputs can
variously cause the generated voices to be turned on or off, to
pass a direct copy of a non-voiced fricative source, or to
harmonize the source according to some constructed algorithm.
The transition from one mode to another is cross-faded, giving
seemless alternating between voiced (harmonized) and non-voiced
fricatives during spoken or sung input.
</p>
<p>
<span class="emphasis"><em>harmon2</em></span>, <span class="emphasis"><em>harmon3</em></span>,
<span class="emphasis"><em>harmon4</em></span> are especially matched to the output
of <span class="emphasis"><em>specptrk</em></span>. The latter generates pitch
data in decimal octave format; it also emits its base value if
no pitch is identified (as in fricative noise) and emits zero if
the energy falls below a threshold, so
that <span class="emphasis"><em>harmon2</em></span>, <span class="emphasis"><em>harmon3</em></span>,
<span class="emphasis"><em>harmon4</em></span> can be set to pass the direct
signal in both cases. Of course, any other form of pitch
estimation could also be used. Since pitch trackers usually
incur a slight delay for accurate estimation
(for <span class="emphasis"><em>specptrk</em></span> the delay is printed by the
<span class="emphasis"><em>spectrum</em></span> unit), it is normal to delay the audio signal by the
same amount so that <span class="emphasis"><em>harmon2</em></span>,
<span class="emphasis"><em>harmon3</em></span>, <span class="emphasis"><em>harmon4</em></span>
can work from a fully concurrent estimate.
</p>
</div>
<div class="refsect1" title="Examples">
<a id="id2938490"></a>
<h2>Examples</h2>
<p>
Here is an example of the harmon2 opcode. It uses the file <a class="ulink" href="examples/harmon.csd" target="_top"><em class="citetitle">harmon.csd</em></a>.
</p>
<div class="example">
<a id="id2938506"></a>
<p class="title">
<b>Example 295. Example of the harmon2 opcode.</b>
</p>
<div class="example-contents">
<pre class="programlisting">
a1,a2 <span class="opc">ins</span> <span class="comment">; get mic input</span>
w1 <span class="opc">spectrum</span> a1, .02, 7, 24, 12, 1, 3 <span class="comment">; and examine it</span>
koct,kamp <span class="opc">specptrk</span> w1, 1, 6.5, 9.5, 7.5, 10, 7, .7, 0, 3, 1
a3 <span class="opc">delay</span> a1, .065 <span class="comment">; allow for ptrk delay</span>
a4 <span class="opc">harmon2</span> a3, koct, 1.25, 0.75, 0, 6.9 <span class="comment">; output a fixed 6-4 harmony</span>
<span class="opc">outs</span> a3, a4 <span class="comment">; as well as the original</span></pre>
</div>
</div>
<p><br class="example-break" />
</p>
</div>
<div class="refsect1" title="Credits">
<a id="id2938588"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Barry L. Vercoe</td>
</tr>
<tr>
<td>M.I.T., Cambridge, Mass</td>
</tr>
<tr>
<td>2006</td>
</tr>
</table>
<p>
</p>
<p>New in version 5.04</p>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="harmon.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="OpcodesTop.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="hilbert.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">harmon </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> hilbert</td>
</tr>
</table>
</div>
</body>
</html>
