<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<font face="Calibri">It is disappointing to see that the same
misunderstandings come back and again. In such conditions, the
whole discussion is pointless. Let me try for the last time:<br>
<br>
1. The question of enharmonic notes produced on a string or
overblowing a wind instrument and that of harmonic overtones are
only remotely related. Consider the following facts:<br>
– Brass winds usually are built today to play in ET. This is
obtained by complex adjustments of the bore, with the result that
the different notes obtained by overblowing correspond to those in
ET and not to just intonation. Yet, these instruments still can
produce harmonic overtones for each of their notes, the
harmonicity of overtones in this case being more dependent on the
conditions of blowing than on conditions of the bore.<br>
– Clarinets are known not to overblow their even harmonics,
because their reed acts as a closed pipe (i.e. closes when the
wave returns); yet their sounds of course can include all harmonic
overtones.<br>
– Natural pipes (conchs, tusks, horns and the like) are very
unlikely to overblow to harmonic notes, even if they might be
blowed to produce more or less harmonic overtones.<br>
– The production of harmonic notes on a string is dependent on the
kink in the string moving at the same velocity on both sides of
the dividing finger. Velocity is directly dependent on linear
density and section. Making strings with a constant density and
section along their length is a complex technology; strings so
made are called "harmonic strings". Natural strings (e.g. vines,
braided or not) are unlikely to be harmonic.<br>
– If the pipes or strings are not "harmonic" in this sense, they
may still produce different notes in the same conditions as for
harmonic notes, but the intervals between them will not correspond
to those in the harmonic series, and each of them may or may not
include harmonic overtones.<br>
<br>
2. The conditions for producing harmonic overtones are described
by Fourier's theorem. They reduce to one, periodicity. A truly
periodic vibration produces a stable pitch, and a stable pitch
produces harmonic overtones. Reducing the stability reduces the
harmonicity of the overtones, until the concepts of pitch and of
overtones loose pertinence.<br>
– Vibrato, for instance, by disturbing the stability of pitch,
reduces the harmonicity of the overtones (which allows more easily
playing 'in tune', as the fusion of the overtones becomes somewhat
blurred).<br>
– Slightly non-harmonic strings may appear to produce stable
pitches, but yet become difficult to tune (this was the case with
early nylon harp strings, because it was difficult to maintain a
constant diameter on such lengths).<br>
– Pipes or strings that are significantly non harmonic in the
definition under 1 above cannot be forced to produce stable
pitches and therefore do not produce harmonic overtones. <br>
– Stability of pitch requires a sustained supply of energy, as is
the case with winds and bowed strings. It can be approximated by a
high initial supply of energy and a slow dissipation, as in pianos
and some plucked string instruments. Percussion instruments do not
normally produce harmonic overtones (see for instance
<a class="moz-txt-link-freetext" href="http://soundmath.blogspot.be/2010/08/percussion-instruments.html">http://soundmath.blogspot.be/2010/08/percussion-instruments.html</a>).<br>
<br>
3. About Pythagoras and the smithy, Calvin Bower writes in the
Cambridge History of Wester Music Theory that "The roots of this
myth so fundamental to the history of Western musical thought are
buried within ancient values and archetypes that can never be
fully fathomed. The empirical data offered in the myth is wholly
specious, for hammers of comparable weights would not sound the
musical intervals presented in the story. However, the myths and
dreams of a civilization are judged not by their empirical truth
or falsity, but by the expression of intellectual and spiritual
complexes they reveal within a culture."<br>
...The myths and dreams of some SMT-Talk participants
similarly must be judged by their expression of intellectual and
spiritual complexes...<br>
<br>
Nicolas Meeùs<br>
Professeur émérite<br>
Université Paris-Sorbonne<br>
<a class="moz-txt-link-abbreviated" href="mailto:nicolas.meeus@scarlet.be">nicolas.meeus@scarlet.be</a><br>
<br>
<br>
<br>
</font>
<div class="moz-cite-prefix">Le 22/07/2014 23:03, CARSON FARLEY a
écrit :<br>
</div>
<blockquote
cite="mid:1457031109.24573810.1406063028922.JavaMail.root@embarqmail.com"
type="cite"><span style="background-color: rgb(255, 255, 255);">If
I pick up my guitar or bass I can produce strong harmonics</span></blockquote>
<br>
</body>
</html>