A New or Improved Method of Constructing Stringed Instruments.
Year: 1891

page_text: Date of Application, 19th Aug., 1891-Accepted, 13th Sept., 1891
COMPLETE SPECIFICATION.
A New or Improved Method of Constructing Stringed Instruments.
A communication to me from ALFRED STELZNER, of Wiesbaden, in the Empire
of Germany, Doctor.
I, EDMUND EDWARDS, of the firm of Edwards and Co., Patent Agents and
Engineers, of 35, Southampton Buildings, Chancery Lane, in the County of
Middlesex, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement and accompanying drawing, that is to say :—
This invention is intended to be applied to four stringed instruments, (inde-
pendently of the double bass,) that is to say, a violin, a viola, a violetta, and a
violoncello, the violetta being a newly designed instrument the pitch of which is an
octave lower than that of the violin, so that it forms an intermediate instrument
between the violin and the violoncello, being played upon like a violin and
designed to take the part of a second violin in a string quartette (Chamber
music), so as to fill up the hitherto existing gap in the interpretation of a part of
orchestral music.
The newly designed stringed instrument which forms the subject of the
present invention differs from those hitherto ordinarily constructed, in four principal
points:
1. In the shape of its outline.
2. In the shape and use of the two blocks or sound posts connecting the ends of
the belly and the back.
3. In the shape of the sides.
4. In the shape of the sound holes.
From acoustic experiments and calculations the inventor has discovered that the
power and fulness of sound in stringed instruments can be considerably increased,
so that a peculiarly grand tone is obtained, when the various parts of the
instruments are so formed as to ensure the most favourable conditions to promote
the efficiency of the sonorous sound waves. The novel method of construction may
be applied to all such instruments without it being necessary to alter their usual
length.
The construction of instruments such as hitherto used, has been based either
upon the imitation of celebrated patterns, or on the directions given by a certain
Antonio Bagatella, whose rules are entirely empirical and without any theoretical
basis. According to these rules the outline of the instrument is formed of curves
or segments of circles subsequently joined together. According to the calculations
of the present inventor, the ends of the belly and back of the resonant chamber,
that is to say the curves a, b, c, and a, b, c, in Figure 1 of the accompanying
drawing, should not be drawn as shewn in dotted lines as connected segments, but as
shewn in black lines as true ellipses, and the upper and lower ellipses should have a
definite proportion to each other.
When such elliptic forms are used, the sonorous waves are produced in the most
favourable conditions for effective resonance, as they strengthen instead of enfeebling
one another so that the vibrations of the molecules of air can develop the greatest
energy. The first improvement is therefore the formation of the upper and lower
parts of the resonant chamber of an elliptical shape.
Intimately connected with this method of construction is the improved form of the
sound posts or blocks A. which connect the ends of the belly and the back inside
the instrument.
These blocks have hitherto served mainly as supports, and have been made of
any convenient shape, as shewn in Figure 2.

page_text: No attention has been bestowed upon their effect upon the vibrating air wave,
and the second part of the present invention relates to an improved form given to
them, which in combination with the elliptical outline of the instrument as above
described, will have no disturbing influence on the air waves, but will rather have
a beneficial effect, their curved surfaces d, e, forming parabolas whose foci, axes, andi
diameters, are in such a ratio with the elliptical outlines a, b, c, a, b, c', that the,
sonorous waves are everywhere intensified.
The second improvement in the new instrument consists therefore in the parabolic
form of the two sound blocks or posts A.
The parabolic form also plays an important part in the formation of the sides of
the instrument. In stringed instruments as hitherto constructed, when the sides
are not of uniform height for their full length as indicated by the outlines f, g, h, i,
Figure 3, they are slightly higher at the lower than at the upper end of the
instrument, this reduction in height being adopted to improve the appearance.
The new instrument on the other hand is provided with sides the outlines of
which form parabolic curves, which may be either simple or compound. The
curve k, l, m, shews a parabola of the first and the curve n, 1, 0, a parabola of the
second kind. The lower outlines of the sides, which are made considerably higher
than in the instruments hitherto made, have also a parabolic curvature.
The belly of the instrument is made in the usual way of a plate or board glued
upon the edges of the parabolic sides and tightly pressed thereon by means of
screw clamps.
A further improvement in the novel instrument relates to the sound holes.
The curved ends and the central slot of these sound holes, cut in the belly of the
instrument, form the outlines of the tongue like parts B B. In order to improve
the vibration of these parts they have been lengthened, as compared with the
corresponding vibrating tongues hitherto used, so that the length of the parts
formed in the ordinary way (Figure 2), is much less than the length y (Figure 1)
of the tongues in the improved instrument. In this way an increased vibration of
the tongues is obtained and the sound intensified.
In the above description the exact position of the foci, and the extent and
proportion of curvature of the elliptical and parabolic curves described, are not
rigidly fixed, as the limits of variation of these proportions and curvatures are
considerable, according to the size and the character of the instrument. The
essential feature of the invention is the selection, instead of the arbitrary curves
or outlines hitherto used, of elliptic and parabolic lines the curves of which have
such relative proportions that the sonorous waves formed shall produce resonance
under the most favourable conditions. The forms of the curves will thus always
depend upon each other so that the selection of one must determine at the same
time the form of the other.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
In stringed instruments the elliptical formation of the outline a, b, c, of the belly
and back, the parabolic shape of the surfaces d, e, of the two posts or blocks A
which connect the belly to the back, the formation of the upper and lower outlines
of the sides by means of parabolic curves, and the prolongation of the tongues B by
the extension of the sound holes, whereby all these curves and the relative
proportions of their curvatures are such that the surfaces outlined thereby result
in the most favourable acoustic conditions for the production and action of the
sonorous waves.
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicant.