You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
176 lines
6.2 KiB
176 lines
6.2 KiB
<!DOCTYPE html>
|
|
|
|
<!--Converted with LaTeX2HTML 2002-2-1 (1.71)
|
|
original version by: Nikos Drakos, CBLU, University of Leeds
|
|
* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan
|
|
* with significant contributions from:
|
|
Jens Lippmann, Marek Rouchal, Martin Wilck and others -->
|
|
<HTML>
|
|
<HEAD>
|
|
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
|
|
|
|
|
<TITLE>Octave divider and formant adder</TITLE>
|
|
<META NAME="description" CONTENT="Octave divider and formant adder">
|
|
<META NAME="keywords" CONTENT="book">
|
|
<META NAME="resource-type" CONTENT="document">
|
|
<META NAME="distribution" CONTENT="global">
|
|
|
|
<META NAME="Generator" CONTENT="LaTeX2HTML v2002-2-1">
|
|
<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css">
|
|
|
|
<LINK REL="STYLESHEET" HREF="book.css">
|
|
|
|
<LINK REL="next" HREF="node83.html">
|
|
<LINK REL="previous" HREF="node81.html">
|
|
<LINK REL="up" HREF="node80.html">
|
|
<LINK REL="next" HREF="node83.html">
|
|
</HEAD>
|
|
|
|
<BODY >
|
|
<!--Navigation Panel-->
|
|
<A ID="tex2html1774"
|
|
HREF="node83.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="next.png"></A>
|
|
<A ID="tex2html1768"
|
|
HREF="node80.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="up.png"></A>
|
|
<A ID="tex2html1762"
|
|
HREF="node81.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="prev.png"></A>
|
|
<A ID="tex2html1770"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="contents.png"></A>
|
|
<A ID="tex2html1772"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A ID="tex2html1775"
|
|
HREF="node83.html">Waveshaping and difference tones</A>
|
|
<B> Up:</B> <A ID="tex2html1769"
|
|
HREF="node80.html">Examples</A>
|
|
<B> Previous:</B> <A ID="tex2html1763"
|
|
HREF="node81.html">Ring modulation and spectra</A>
|
|
<B> <A ID="tex2html1771"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A ID="tex2html1773"
|
|
HREF="node201.html">Index</A></B>
|
|
<BR>
|
|
<BR>
|
|
<!--End of Navigation Panel-->
|
|
|
|
<H2><A ID="SECTION00952000000000000000">
|
|
Octave divider and formant adder</A>
|
|
</H2>
|
|
<A ID="sect5.octave"></A>
|
|
<P>
|
|
As suggested in Section <A HREF="node77.html#sect5.ringmod">5.2</A>, when considering the result of
|
|
modulating a complex harmonic (i.e., periodic) signal by a sinusoid, an
|
|
interesting special case is to set the carrier oscillator to <IMG
|
|
WIDTH="27" HEIGHT="32" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img98.png"
|
|
ALT="$1/2$"> the
|
|
fundamental frequency, which drops the resulting sound an octave with only
|
|
a relatively small deformation of the spectral envelope. Another is to
|
|
modulate by a sinusoid at several times the fundamental frequency, which
|
|
in effect displaces the spectral envelope without changing the fundamental
|
|
frequency of the result. This is demonstrated in Example E03.octave.divider.pd (Figure
|
|
<A HREF="#fig05.10">5.10</A>). The signal we process here is a recorded, spoken voice.
|
|
|
|
<P>
|
|
|
|
<DIV ALIGN="CENTER"><A ID="fig05.10"></A><A ID="5803"></A>
|
|
<TABLE>
|
|
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 5.10:</STRONG>
|
|
Lowering the pitch of a sound by an octave by determining its pitch
|
|
and modulating at half the fundamental.</CAPTION>
|
|
<TR><TD><IMG
|
|
WIDTH="359" HEIGHT="371" BORDER="0"
|
|
SRC="img487.png"
|
|
ALT="\begin{figure}\psfig{file=figs/fig05.10.ps}\end{figure}"></TD></TR>
|
|
</TABLE>
|
|
</DIV>
|
|
|
|
<P>
|
|
The subpatches <TT>pd looper</TT> and <TT>pd delay</TT> hide details. The
|
|
first is a looping sampler as introduced in Chapter <A HREF="node26.html#chapter-wavetable">2</A>.
|
|
The second is a delay of 1024 samples, which uses objects that are introduced
|
|
later in Chapter <A HREF="node104.html#chapter-delay">7</A>. We will introduce one object class here:
|
|
|
|
<P>
|
|
<BR><!-- MATH
|
|
$\fbox{ \texttt{fiddle\~}}$
|
|
-->
|
|
<IMG
|
|
WIDTH="78" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img488.png"
|
|
ALT="\fbox{ \texttt{fiddle\~}}">:
|
|
<A ID="5955"></A>pitch tracker. The inlet takes a signal to analyze, and messages to
|
|
change settings. Depending on its creation arguments <TT>fiddle~</TT>may have a
|
|
variable number of outlets offering various information about the input
|
|
signal. As shown here, with only one creation argument to specify window size,
|
|
the third outlet attempts to report the pitch of the input, and the amplitude
|
|
of that portion of the input which repeats (at least approximately) at the
|
|
reported pitch. These are output as a list of two numbers. The pitch, which
|
|
is in MIDI units, is reported as zero if none could be identified.
|
|
|
|
<P>
|
|
In this patch the third outlet is unpacked into its pitch and amplitude
|
|
components, and the pitch component is filtered by the <TT>moses</TT> object so that
|
|
only successful pitch estimates (nonzero ones) are used. These are
|
|
converted to units of frequency by the <TT>mtof</TT> object. Finally, the frequency
|
|
estimates are either reduced by <IMG
|
|
WIDTH="27" HEIGHT="32" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img98.png"
|
|
ALT="$1/2$"> or else multiplied by 15, depending on
|
|
the selected multiplier, to provide the modulation frequency. In the first
|
|
case we get an octave divider, and in the second, additional high harmonics
|
|
that deform the vowels.
|
|
|
|
<P>
|
|
<HR>
|
|
<!--Navigation Panel-->
|
|
<A ID="tex2html1774"
|
|
HREF="node83.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="next.png"></A>
|
|
<A ID="tex2html1768"
|
|
HREF="node80.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="up.png"></A>
|
|
<A ID="tex2html1762"
|
|
HREF="node81.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="prev.png"></A>
|
|
<A ID="tex2html1770"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="contents.png"></A>
|
|
<A ID="tex2html1772"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A ID="tex2html1775"
|
|
HREF="node83.html">Waveshaping and difference tones</A>
|
|
<B> Up:</B> <A ID="tex2html1769"
|
|
HREF="node80.html">Examples</A>
|
|
<B> Previous:</B> <A ID="tex2html1763"
|
|
HREF="node81.html">Ring modulation and spectra</A>
|
|
<B> <A ID="tex2html1771"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A ID="tex2html1773"
|
|
HREF="node201.html">Index</A></B>
|
|
<!--End of Navigation Panel-->
|
|
<ADDRESS>
|
|
Miller Puckette
|
|
2006-12-30
|
|
</ADDRESS>
|
|
</BODY>
|
|
</HTML>
|
|
|