Music Trade Review

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THE MUSIC TRADE
REVIEW
13
We may summarize these general axioms as fol-
lows:
1. In sound-boards the greatest tonal effi-
Discussed in a Series of Interesting Papers—Theory and Practice of Pianoforte Construction
ciency is attainable only when the vibrating
Defined—Deductions from Sound Board and Belly Bridge Analysis—Laying out the Scale
surface is as large as the limits of the instru-
—The Grand Pianoforte and Its Improvement—Some Reflections Thereon.
ment's size permits.
2. The material of which the sound-board is
(Written Especially for The Review)—Copyrighted.
the sound-board—the belly-bridges, as we have constructed must possess great elasticity and at
ARTICLE VI.
called them. In some makes of pianos the line the same time be freely susceptible to the im-
In the last article of this series a number of
pression on it of the vibrations of the sounding-
suggestions were made regarding possible and of the bridge construction is permitted to be
strings.
broken
wherever
there
is
a
corresponding
break
desirable improvements in the accepted style of
3. The most suitable material for this pur-
sound-board construction. The suggestions to- in the hammer line caused by the interposition
pose is the wood of the spruce-fir, and the re-
of
the
various
braces
of
the
iron
frame.
The
ward betterment which were there made are
quired elasticity is given to boards so constructed
quite likely to be disputed, but it is surely in- obvious result of such a method of construction
either by the addition of ribs or by the dupli-
is
that
the
resonance
of
the
board
is
much
contestable that, whatever be the value of the
cation of the board with another of similar ma-
latter, the usual style of construction is neither interfered with and the consequent tonal effi-
terial, but with the grain running at right angles
ciency
of
the
instrument
lessened.
For
it
is
easy
acoustically correct nor musically satisfying.
to the grain of the former.
But there are more evils yet to be noted, for to see that if the bridge line be broken at any
4. Of the two methods of construction thus
not only does the sound-board, as usually point, the vibrations that are carried from any
outlined the latter is the more scientific, and,
sounding
string
along
the
bridge
to
the
surface
built, suffer from inherent faults of design,
caetetris paribus, preferable.
but the methods employed in fitting it into the of the sound-board will be stopped at the break
5. The construction of the board should be
and
will
be
unable
to
reach
those
parts
of
the
rest of the pianoforte are often faulty. In fact,
arranged
so that all strains, except the more
there are few makes indeed where the sound- board, that are remote from its path, with
or less rectilinear and direct torsions imposed
rapidity
and
ease.
Incontestably,
therefore,
the
board is not subjected to a large proportion of
by the pressure of the strings upon the bridge
the tensile and torsional strains that are im- bridge line should, if possible, be continuous.
may, as far as possible, be avoided.
Many
manufacturers,
however,
while
apparently
posed upon the entire structure by the pull of the
6. Greater prominence of the upper partials
stretched strings. The burden of these strains recognizing the force of this proposition, seem to
being desirable as far as concerns the resonant
be
afraid
to
follow
it
out
to
its
logical
conclusion.
is far too great for any wooden construction, and
influence of the board upon them, it seems proper
the usual results quickly follow, namely, gradual They are willing to make the line of bridge
to attempt to increase the elasticity of the board,
continuous
until
the
end
of
the
plain
wire
deterioration and ultimate splitting.
and a system of screw-compression, as already
It is, of course, true enough that the mere strings is reached. After that point they seem
practiced, furnishes to a certain extent a prac-
to
think
that
it
is
no
longer
necessary
that
con-
fact that the belly-bridge rests upon the sound-
tical solution.
board, and that the strings rest upon the bridge tinuity of communication between the various
7. The line of the belly-bridges should be con-
make it inevitable that the board should be more sounding members of the scale should subsist.
tinued unbroken throughout the entire compass
or less directly affected by the tension to which This idea is, of course, quite fallacious. The
of the instrument, and the bass bridge should
the strings are submitted. This .strain ought bass strings are simply a continuation of the
always be connected with the others.
higher
ones,
and
are,
in
fact,
precisely
similar
to be in one direction only and should be tor-
8. Building up of the belly-bridges in succes-
except
in
regard
to
the
details
of
thickness
and
sional rather than tensile. If, indeed, care be
sive layers of hard wood presents many advant-
length.
Moreover,
it
is
quite
as
important
that
taken that the sound-board is not subjected to
ages and the construction can be further im-
any avoidable strains other than those direct the portions of the board over which the bass
proved by adopting end-grain instead of cross-
bridge
exercises
control
should
be
made
freely
torsions necessitated by the bearing down of the
grain wood.
resonant,
as
it
is
that
this
process
should
be
strings upon the belly-bridge, and if the con-
Laying Out the Scale.
applied
to
the
others.
The
bass
bridge
ought
struction be so arranged that the other strains
We have now reached the point where it be-
are, as far as possible, taken up and sustained invariably, therefore, to be connected with the
comes practicable to examine the problems in-
by the iron framing, then much of tone deteriora- bridges that serve the rest of the strings.
Method of Building Belly Bridges.
volved in the actual laying out of a pianoforte
tion will be avoided and the efficient life of the
structure greatly prolonged.
It may further properly be remarked that ecale. We have surveyed the field of sound
Advantages of Sound-Board Compression.
there are interesting and complicated problems phenomena as developed by the strings and the
to
be overcome in choosing the material and the cognate phenomena of resonance as exhibited by
A further matter must be noted in reference
to the reinforcing properties of sound-boards. It exact method of building the belly-bridges. It the reinforcing departments of the instrument.
is desired to combine extreme facility of vibra- The examination thus made has enabled us to
will be recollected that in the earlier portion of
this series we found it proper to observe that tion with the requisite resisting power. In other formulate a number of important general prin-
certain upper partials of the notes generated by words, the bridge must allow the fullest possi- ciples. It now becomes our business to apply these
the strings must be emphasized with relatively ble scope to the impressed vibrations from the principles to the actual task of design. It will
great prominence, in order that the resultant strings and, at the same time, must possess such be noted, however, that the laws already evolved
sounds may possess that richness and color that strength that it can successfully resist the tor- are necessarily general and abstract. They deal
is essential to good pianoforte tone. This desir- sions imposed upon it by the pull of the strings. with the very broadest kind of investigation, and
able consummation may be assisted by increas- The only method that appears to be thoroughly their application is therefore bound to be sub-
ing the elasticity of the sound-board. Even if
practical and, at the same time, acoustically cor- jected to a certain amount of modification and
the double, non-ribbed style of construction be rect, is one which most manufacturers have had adaptation, according to the specific requirements
used there is still a lack of elasticity, and the the acuteness to adopt already. The bridge, ac- of the individual instrument. This is not to say,
ordinary method of construction is still more cording to this method, is built up of a number however, that we shall find it necessary to alter
open to this defect. The only practicable man- of layers of hard wood (generally maple) which our general views in regard to the phenomena of
ner of augmenting the elasticity seems to lie in are glued together in such a way that the grain tone production, but only that it is not always
the direction of compressing the material of
of each layer crosses that of the other. In this either essential or desirable to press the princi-
which the board is constructed. Such a method way both the requisite strength and more or less ples too ruthlessly to their logical conclusions.
The three prevailing forms in which piano-
has been successfully carried out by an eminent facility of vibration are obtained. But i t has
designer of Boston with results that seem to be remained for one distinguished piano maker to fortes are wont to be cast are those known as
excellent. The device employed to reach this go a step further, and to apply thoroughly scien- the grand, the square, and the upright. There
result consists of a number of compression tific methods to tne design of belly-bridges. In have been at various times other forms more or
screws, the tension of which can be adjusted at the instruments made by him, he has built the less dissimilar to these, but as this series of
will and which are placed on the under side of bridges in such a way that the impressed vibra- articles is not intended to afford a historical
the sound-board. In this manner the fibers of tions will travel in the line of the grain instead view of the pianoforte design, we shall confine
the wood can be squeezed together and its elas- of across it. The bridges, in fact, are built of
our observations to the three forms mentioned
ticity thus greatly and advantageously increased. end-grain and not, as is general, of cross-grain above.
In course of time the screws will have to be re- wood. This ingenious and simple device facili-
The Grand Pianoforte.
adjusted, and the device has not been in use for tates the passage of the impressed vibrations
Of
these
the
grand is at once the most famous
a sufficient length of time to enable one to judge and, in consequence, tends to impart a greater
and
the
oldest.
It is, in fact, the classic form
of its merits with absolute accuracy. Undoubt- clarity to the various partials of the compound
edly, however, some method of compression is tones. Some existing pianofortes might be and a direct descendant from the harpsichord.
Indeed, the original piano of Cristofori (as now
desirable to secure for the sound-board the full greatly improved as to their clarity of speech if
restored and in the Metropolitan Museum of Art,
measure of efficiency.
a similar device for increasing the power of Mew York), is simply a harpsichord with a ham-
Of the required shape of the sound-board little resonance were fitted to them.
mer action substituted for the usual jacks and
need be said. I t must in all cases follow the
quills. Cristofori, whose claim of priority of in-
General Deductions.
general outline of the instrument's case. Thus
The above brief and condensed survey of the vention has lately been confirmed, realized, to-
the shape of the board in a grand piano will phenomena connected with the sound-board and gether with many other harpsichord players and
naturally be quite different from that of an up- belly-bridges has enabled us to observe that there builders, the disadvantages under which that in-
right, and in a square the form will be dis- are certain general rules that may be properly strument labored. Incapable of dynamic effects
similar to either of the others.
without extraneous assistance, the harpsichord
applied to all questions which the designing of
A word remains to be said of the bridges upon these members of the pianoforte body may raise. was always unsatisfactory. It occurred to the In-
THE PROBLEM O^PIANO SCALE DESIGN-