176 lines
5.9 KiB
HTML
176 lines
5.9 KiB
HTML
<!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>Controlling reverberators</TITLE>
|
|
<META NAME="description" CONTENT="Controlling reverberators">
|
|
<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="previous" HREF="node111.html">
|
|
<LINK REL="up" HREF="node111.html">
|
|
<LINK REL="next" HREF="node113.html">
|
|
</HEAD>
|
|
|
|
<BODY >
|
|
<!--Navigation Panel-->
|
|
<A ID="tex2html2226"
|
|
HREF="node113.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="next.png"></A>
|
|
<A ID="tex2html2220"
|
|
HREF="node111.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="up.png"></A>
|
|
<A ID="tex2html2216"
|
|
HREF="node111.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="prev.png"></A>
|
|
<A ID="tex2html2222"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="contents.png"></A>
|
|
<A ID="tex2html2224"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A ID="tex2html2227"
|
|
HREF="node113.html">Variable and fractional shifts</A>
|
|
<B> Up:</B> <A ID="tex2html2221"
|
|
HREF="node111.html">Artificial reverberation</A>
|
|
<B> Previous:</B> <A ID="tex2html2217"
|
|
HREF="node111.html">Artificial reverberation</A>
|
|
<B> <A ID="tex2html2223"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A ID="tex2html2225"
|
|
HREF="node201.html">Index</A></B>
|
|
<BR>
|
|
<BR>
|
|
<!--End of Navigation Panel-->
|
|
|
|
<H2><A ID="SECTION001161000000000000000">
|
|
Controlling reverberators</A>
|
|
</H2>
|
|
|
|
<P>
|
|
Artificial reverberation is used almost universally in recording or sound
|
|
reinforcement to sweeten the overall sound. However, and more interestingly,
|
|
reverberation may be used as a sound source in its own right. The special case
|
|
of infinite reverberation is useful for grabbing live sounds
|
|
and extending them in time.
|
|
|
|
<P>
|
|
To make this work in practice it is necessary to open the input of the
|
|
reverberator only for a short period of time, during which the input sound is
|
|
not varying too rapidly. If an infinite reverberator's input is left open for
|
|
too long, the sound will collect and quickly become an indecipherable mass. To
|
|
"infinitely reverberate" a note of a live instrument, it is best to wait until
|
|
after the attack portion of the note and then allow perhaps 1/2 second of the
|
|
note's steady state to enter the reverberator. It is possible to build chords
|
|
from a monophonic instrument by repeatedly opening the input at different
|
|
moments of stable pitch.
|
|
|
|
<P>
|
|
|
|
<DIV ALIGN="CENTER"><A ID="fig07.16"></A><A ID="8114"></A>
|
|
<TABLE>
|
|
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 7.16:</STRONG>
|
|
Controlling a reverberator to capture sounds selectively: (a)
|
|
the network; (b) examples of how to control the input gain and feedback to
|
|
capture two sounds at times <IMG
|
|
WIDTH="16" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img37.png"
|
|
ALT="$t_1$"> and <IMG
|
|
WIDTH="16" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img38.png"
|
|
ALT="$t_2$">, and to hold them until a later
|
|
time <IMG
|
|
WIDTH="16" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img39.png"
|
|
ALT="$t_3$">.</CAPTION>
|
|
<TR><TD><IMG
|
|
WIDTH="449" HEIGHT="484" BORDER="0"
|
|
SRC="img780.png"
|
|
ALT="\begin{figure}\psfig{file=figs/fig07.16.ps}\end{figure}"></TD></TR>
|
|
</TABLE>
|
|
</DIV>
|
|
|
|
<P>
|
|
Figure <A HREF="#fig07.16">7.16</A> shows how this can be done in practice. The two most
|
|
important controls are the reverberator's input and feedback
|
|
gains. To capture a sound, we set the feedback gain to one (infinite
|
|
reverberation time) and momentarily open the input at time <IMG
|
|
WIDTH="16" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img37.png"
|
|
ALT="$t_1$">. To add other
|
|
sounds to an already held one, we simply reopen the input gain at the
|
|
appropriate moments (at time <IMG
|
|
WIDTH="16" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img38.png"
|
|
ALT="$t_2$"> in the figure, for example). Finally, we
|
|
can erase the recirculating sound, thus both fading the output and emptying the
|
|
reverberator, by setting the feedback gain to a value less than one (as at time
|
|
<IMG
|
|
WIDTH="16" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img39.png"
|
|
ALT="$t_3$">). The further we reduce the feedback gain, the faster the output will
|
|
decay.
|
|
|
|
<P>
|
|
<HR>
|
|
<!--Navigation Panel-->
|
|
<A ID="tex2html2226"
|
|
HREF="node113.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="next.png"></A>
|
|
<A ID="tex2html2220"
|
|
HREF="node111.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="up.png"></A>
|
|
<A ID="tex2html2216"
|
|
HREF="node111.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="prev.png"></A>
|
|
<A ID="tex2html2222"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="contents.png"></A>
|
|
<A ID="tex2html2224"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A ID="tex2html2227"
|
|
HREF="node113.html">Variable and fractional shifts</A>
|
|
<B> Up:</B> <A ID="tex2html2221"
|
|
HREF="node111.html">Artificial reverberation</A>
|
|
<B> Previous:</B> <A ID="tex2html2217"
|
|
HREF="node111.html">Artificial reverberation</A>
|
|
<B> <A ID="tex2html2223"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A ID="tex2html2225"
|
|
HREF="node201.html">Index</A></B>
|
|
<!--End of Navigation Panel-->
|
|
<ADDRESS>
|
|
Miller Puckette
|
|
2006-12-30
|
|
</ADDRESS>
|
|
</BODY>
|
|
</HTML>
|