Music Trade Review

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Fretted Instruments
THEIR ORIGIN,
DEVELOPMENT
and M A R K E T I N G
Second of a Scries of Articles on Fretted
Instruments
Andres Segovia
By LLOYD LOAR
I
N order to appreciate the possibilities of
what an instrument can do, it is wise to
first obtain a general idea of how it does
it. So we will devote a little time to the
acoustics of fretted instruments, not as scien-
tists, however, but as merchandisers and
players of these instruments.
In general, all stringed instruments produce
tone in the same way. First, the string vibrates
a certain number of times per second, this
vibration rate being controlled by the length,
tension, diameter and material of the string.
String vibration, by the way, is a complex
performance.
When we
hear one tone in a guitar,
for instance, a great many
vibration rates are repre-
sented in it. These com-
ponents of tone are known
as "partials," or fundamen-
tal and overtones, and
have somewhat the same
relation to the resulting
tone as the seven primary
colors do to the ray of
white light which they
compose. The lowest in
pitch of these partials,
also known as the funda-
mental or first partial,
determines the pitch of
the tone we hear, while
the rest of the partials
determine its color or
character. These partials
have a definite relationship
to each other, governed by
the ratio of whole num-
bers—that is, if the first
partial has a vibration fre-
quency of 100 per second,
the second one would have
a frequency of 200, the
third of 300, and so on. If
the partials present went
as far as the sixteenth, it
would have a frequency of 1,600 per second.
The percentage of each of the partials to the
whole tone is what determines the color of the
tone; and if it were possible to produce a man-
dolin, a banjo, a violin, a piano and a saxo-
phone, each of which produced a tone with
exactly the same number and ratio of partials,
they would all sound exactly alike. This, of
course, is not possible.
When a string is
stopped by a metal fret at one end, a bridge
of dense material at the other, and is vibrated
by being picked, a certain number and ratio
Eminent Spanish guitarist, from a painting by
Miguel del Pino
of partials is encouraged that gives what has
come to be known as fretted instrument or
plucked string tone. Improvement in the in-
strument's design may greatly improve the
quality and increase the quantity of tone pro-
duced, but the original number and ratio of
partials will be adhered to closely enough so
that the tone is still fretted instrument tone.
The bridge acts as a lever to turn these
string vibrations downward into the sound-
board and also to increase their strength by
reducing their amplitude, concentrating them
—in other words. The soundboard or top is
As the top and back move into and then away
from the outside air they produce the series
of condensations and rarefactions known as
a sound wave, the pulsating air inside the body
contacts with the outside air through the
soundholes, adds its bit to the sound-wave pat-
tern, and the total result is the tone we hear
from the instrument.
In different designs of instruments the top,
back and air chamber favor certain partials
at the expense of others, so the tone of these
different designs is not equally good. In some
of them the fundamental or first partial is neg-
lected and the tone sounds
thin or shrill. In others
the fundamental may be
favored too much and the
tone lacks vitality. Many
variations arc possible. The
banjo family has only a
vibrating top or calfskin
head; the back, or reso-
nator, and rim not vibrat-
ing in a way that produces
tone. But the head is so
light in weight and its re-
sponse to the string can
be so effectively speeded
up by tension on the head
through the tension hooks,
that it vibrates violently
enough to make up for
this.
Fretted instrument tone
is characterized by an
impact or comparatively
powerful tone as the string
is struck and a rapid
diminution of i n t e n s i t y
until the tone ceases. The
tone sustains an appre-
ciable length of time, but
1—Modern flat top guitar (Martin). 2—Rim of un-
if a long-sustained tone of
finished modern mandolin. 3—Cross section of mod-
ern mandolin. 4—Unfinished top of modern arched
considerable power is de-
top mandolin. (2, 3 and 4, Gibson.)
sired the string must be
struck again and again as
pushed down by each string vibration through rapidly as possible by the pick or the finger.
the bridge, and pushes itself back and a little And the more powerful the initial tone pro-
beyond the position it occupies when at rest, duced, characteristic of a certain type of in-
through its inherent elasticity. This continues strument, the more quickly it dies away. This
as long as the string vibrates. This sound- is true of any instrument; if the instrument
board and string motion reaches the back has been designed so that all the vibratory
through the rim and the block to which the energy available is used at once the tone is
tailpiece is fastened, the back responds and very powerful, if it is spread out over several
the whole body of the instrument vibrates as seconds of time the tone is correspondingly
a unit. The air contained in the body or box w,eaker. Wind instruments, the strongest-
is also forced to vibrate at the same rates as voiced music-makers we have, will not sustain
(Please turn to page 95)
the strings and the body of the instrument,
91