Improvements in Recording and Speaking Apparatus for Phonographs.
Year: 1897

page_text: Date of Application, 21st Aug., 1897
Complete Specification Left, 9th May, 1898-Accepted, 11th June, 1898
PROVISIONAL SPECIFICATION.
Improvements in Recording and Speaking Apparatus for
Phonographs.
We, PHILIPP VON WOUWERMANS, Engineer, THEODOR FISCHER, Merchant, both of
I Wallfischgasse 4, MAX RAPHAEL KOHN, Merchant, of I Schollenring 23, and IGNAZ
POLAY, Gentleman, of IX Mullnergasse 3, all of Vienna, Austria, do hereby declare
the nature of this invention to be as follows:-
This invention has for object, by suitable construction of the recording knife
and of the reproducing pin of a phonograph, to produce a record of a sound in,
and a reproduction of the said sound from, the cylinder with the greatest possible
uuiformity for the purpose of obviating, in speaking or in recording music, single
sharp or shrill tones which are too prominent, and therefore have a disturbing
effect. This appears to be particularly necessary when the vibrations are intensified
by means of lever mechanisin on the diaphragm. A further object of the invention
is to diminish, as much as possible, the wear and tear of the cylinder.
In the phonographs heretofore usually employed, the knife, as is well known,
has a uniformly sharp cutting edge or surface, in consequence of which, in the case
of a diaphragm which is sensitive to a particular strength of sound those words
and sounds, and especially consonants which are spoken in a lower tone of voice,
are only reproduced in a slight degree, whilst those words or music which have a
very prominent sound as a rule, are cut into the roller. In consequence of this,
single words or vowels become so prominent in the reproducing operation that they
lose in clearness, and in the case of music, a uniform reproduction of the same
cannot be effected with due consideration to the piano parts, for which reason only
loud music can be recorded with the phonographs heretofore usually
employed.
The undulations or corrugations cut into the wax cylinder must therefore, in
order to be able to remedy this serious drawback, correspond as much as possible
In this
to the strength of the sound which is determined by the depth of the cut.
connection, experience has shown that the inclination of the ascending and
descending portions of the incised corrngations is approximately constant, because
the sound waves which correspond to a higher tone and, consequently to a shorter
amplitude of oscillation, do not penetrate so deeply as the waves of a deeper tone
having longer amplitude of oscillation, so that a certain amount of congruence of
the corrugations is produced.
Phonograms of this kind then give good and fine reproductions which correspond
to natural speech and music.
For the purpose of producing such phonograms, there is employed a recording
knife two constructions of which are shown in longitudinal section, and in front
elevation respectively in Figs. 1 and 2, and in Figs. 3 and 4 of the accompanying
drawings.
For reproducing the records made by the aforesaid knife, there is employed a
reproducing pin two forms of which are shown in side elevation in Fig. 5, suitable

page_text: for two different kinds of corrugations, Fig. 6 being a longitudinal section at right
angles to Fig. 5.
As shown in Figs. 1 and 2, the recording knife is made of cone shape at its
end a¹ and is provided with an axial cylindrical hole b. The cone shaped end is
inclined relatively to the phonogram to be produced that is to say to the wax
cylinder and is cut away along the line x-x, starting from the intersection line x
of the cone with the wax surface at right angles, or nearly at right angles to the
phonogram surface.
The truncated cone thereby produced, has at its lower point at x for a very short
extent, a sharp cutting edge which passes upwards on both sides into a scraping
surface that gradually becomes wider (at y in Fig. 2), whilst its edge-angle (the
angle of the generating line of the cone surface with the cutting surface), becomes
gradually more obtuse in the upward direction and therefore exerts a scraping
action. The front cutting surface of a knife of this kind may be an ellipse, a
parabola, or a hyperbola, according to the position of the cut. Instead of this
knife, another arrangement of knife can be employed, consisting of an inverted
cone a bc, which has its base a b turned towards the phonogram surface, as shown
in Figs. 3 and 4. This cone is provided with a cavity a d b, which has the form of
of a hollow cone with a greater apex angle.
By means of the lowest point of intersection b of the two cones, there is produced
a section that is oblique to the base, either along a straight line bfe or along a
curve b g.
In this way, there is produced a recording knife which has the advantage that it
penetrates very readily into the wax roller in the case of sounds and words spoken
in a low tone, whilst, on the contrary, in the case of loud sounds, the action of the
front scraping surface offers a great resistance to an excessive penetration, and
thereby obviates a shrill reproduction of the tone which results from too deep
penetration of the recording instrument.
Knives of this kind record the strength of the tone always in a natural manner,
whereas, on the contrary, the knives which are used in the phonographs heretofore
employed, and which are uniformly sharp all over, catch the wax in the case of loud
sounds and consequently record louder and therefore impure sounds.
The reproducing pin c which is suitable for use with corrugations of the kind
produced by knives constructed as described, has the shape of a two-sided wedge
which in cross section (Fig. 6) at the place of contact with the phonogram
cylinder, has the form of the cutting knife, that is to say, is elliptically, para-
bolically, or byperbolically curved, whilst in the section taken at right angles
to Fig. 6, as shown in Fig. 5, it has two wedge surfaces c¹ that are symetrically
inclined to the junction point of the same, and are directed parallel to the
ascending and descending portions of the corrugatious. A reproducing pin of this
kind will therefore always fit accurately in the recessed portions of the corrugations,
and will lie close up on all sides against the same, whilst however, it will
penetrate more or less into the incised part according to the thickness and depth
of the said incised part.
By this means the pin is secured against lateral oscillations so that no shrill tone
can be produced. Further, the cylinder is not so exposed to wear and tear,
because the reproducing pin does not touch it in one line or in one point only,
as is the case in phonographs heretofore employed, but bears with its entire
lower surface upon the cylinder.
O
1
1007

page_text: Improvements in Recording and Speaking Apparatus for
Phonographs.
We, PHILIPP VON WOUWERMANS, Engineer, THEODOR FISCHER, Merchant, both
of I Wallfischgasse 4, MAX RAPHAEL KOHN, Merchant, of I Schollenring 23,
and IGNAZ PULAY, Gentleman, of IX Mullnergasso 3, all of Vienna, Austria,
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 :-
This invention has for object, by suitable construction of the recording knife
and of the reproducing pin of a phonograph, to produce a record of a sound in,
and a reproduction of the said sound from, the cylinder of a phonograph, with the
greatest possible uniformity for the purpose of obviating, in recording or
reproducing music, sharp or shrill tones which are too prominent and therefore
have a disagreeable effect. This appears to be particularly necessary when the
vibrations are intensified by means of lever mechanism on the diaphragm. A
further object of the invention is to diminish, as much as possible, the wear and
tear of the said cylinder.
In the phonographs heretofore usually employed, the knife, as is well known,
has a uniformly sharp cutting edge or surface, in consequence of which, in the case
of a diaphragm which is sensitive to a particular strength of sound, those words
and sounds, and especially consonants, which are spoken in a lower tone of voice,
are only reproduced in a slight degree, whilst those words or music which have a
very prominent sound as a rule, are cut into the cylinder. In consequence of
this, single words or vowels become so prominent in the reproducing operation
that they lose in clearness, and in the case of music, a uniform reproduction of
the same cannot be effected with due consideration to the piano parts, for which
reason only loud music can be properly recorded with the phonographs heretofore
usually employed.
The undulations or corrugations cut into the wax cylinder must therefore, in
order to be able to remedy. this serious drawback of the prominence of the louder
sounds over the softer ones, correspond as much as possible to the naturally
occurring strength of the sound. In this connection, experience has shown in
correct good phonograms such as have hitherto been seldom obtained, that the
inclination of the ascending and descending portions of the incised corrugations
in the longitudinal direction thereof, is approximately constant, because the sound
waves which correspond to a higher tone, and, consequently to a shorter amplitude
of oscillation, do not penetrate so deeply as the waves of a deeper tone having
longer amplitude of oscillation, so that a certain amount of congruence of the
corrugations is produced.
Phonograms of this kind then give good and fine reproductions which correspond
to natural speech and music.
For the purpose of producing such phonograms, there is employed according to
this invention, a recording knife two constructions of which are shown in
longitudinal section and in front elevation respectively in Figs. 1 and 2, and in
Figs. 3 and 4, of the drawings filed with our Provisional Specification.
For reproducing the records made by the aforesaid knife, there is employed a
reproducing pin which is shown in Figs. 5 and 6, Fig. 5 being a side elevation and
Fig. 6 a longitudinal section at right angles to Fig. 5.
As shown in Figs. 1 and 2, the recording knife a is made of cone shape at its
end a¹ and is provided with an axial cylindrical hole b. The cone shaped end is
inclined relatively to the phonogram to be produced, that is to say to the wax

page_text: cylinder, and is cut away along a line x-x¹, starting from the intersection line x of
the cone with the wax surface, and extending in a direction at right angles, or
nearly at right angles to the phonogram surface. The truncated cone thereby
produced, has at its lower point at x for a very short extent, a sharp cutting edge
which passes upwards on both sides into a scraping surface that gradually becomes
wider (at y in Fig. 2) whilst its edge angle (the angle of the generating line of the
cone surface with the cutting surface) becomes gradually more obtuse in the upward
direction and therefore exerts a scraping action. The front cutting surface of a
knife of this kind may be an ellipse, a parabola, or a hyperbola, according to the
position of the cut. Instead of this knife, another arrangement of knife can be
employed, consisting of an inverted cone a bc, which has its base a b turned
towards the phonogram surface, as shown in Figs. 3 and 4. This cone is provided
with a cavity a d b, which has the form of a hollow cone with a greater apex angle
than the cone a b c. At the lowest point of intersection of the two cones, there is
produced a section that is oblique to the base, either along a straight line bf e or
along a curve b g.
In this way, there is produced a recording knife which has the advantage that it
penetrates very readily into the wax roller in the case of sounds and words spoken
in a low tone, whilst, on the contrary, in the case of loud sounds, the action of the
front scraping surface offers a great resistance to an excessive penetration, and thereby
obviates a shrill reproduction of the tone which results from too deep penetration
of the recording instrument.
Knives of this kind record the strength of the tone always in a natural manner,
whereas, on the contrary, the knives which are used in the phonographs heretofore
employed, and which are uniformly sharp all over, catch in the wax in the case of
loud sounds and consequently record louder and therefore impure sounds.
The reproducing pin c, which is suitable for use with corrugations of the kind
produced by knives constructed in the improved manner herein before described,
has the shape of a two-sided wedge which in cross section (Fig. 6) at the place of
contact with the phonogram cylinder, has the form of the cutting knife, that is to
say, is elliptically, parabolically, or hyperbolically curved, whilst in the section
taken at right angles to Fig. 6, (see Fig. 5) it has two wedge surfaces c¹ that are
symmetrically inclined to the junction point of the same, and are directed parallel to
the ascending and descending portions of the corrugations. A reproducing pin
of this kind will therefore always fit accurately in the recessed portions of the
corrugations, and will lie close up on all sides against the same, whilst however, it
will penetrate more or less into the incised part according to the width and depth
of the said incised part. In Fig. 5, the reproducing pin c is shown in two positions
fitting recessed portions of a corrugated surface of different widths and depths.
By the means described the pin is secured against lateral oscillations so that no
shrill tone can be produced. Further, the phonograph cylinder is not so exposed
to wear and tear as usual, because the reproducing pin does not touch it in one line
or in one point only, as is the case in phonographs heretofore employed, but bears
with its entire lower surface upon the cylinder.
It is to be noted that obviously the size of the recording knife, the material of
which it is made, also the special arrangement of the internal bore b whether central
as shown by way of example in Fig. 1, or eccentric, also its generating line of
rotation and also, as already stated, the size of the angle enclosed by the operative
scraping surfaces and the cylinder, may be varied without departing from the nature
of the invention, the characteristic feature of the improved knife being that it has
an operative surface composed of a cutting point or short cutting edge to which are
connected on each side, scraping surfaces.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what
we claim is :-
2
"A
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page_text: impression in the phonograph cylinder, a recording knife having an operative
surface consisting of a cutting point or a short cutting edge to which are connected
on both sides scraping surfaces of constantly increasing width, substantially as
herein described for the purposes specified.
2. In a phonograph, for the purpose of obtaining great uniformity of strength of
reproduction from a phonograph cylinder, a reproducing pin c in the form of a
double-sided wedge, which as seen in a section taken in the direction of the corru-
gation, that is to say in a section taken across the phonograph cylinder, has two
wedge surfaces c³ which are inclined from the deepest point x of contact
symmetrically to the middle, and which are directed parallel to the rising and falling
portions of the corrugations, whilst as seen in a section taken at any point at right
angles to the above mentioned section, the said wedge has the form of the cutting
edge of the recording knife specified in Claim 1 so that the reproducing pin
conforms closely along its operative surface to the corrugation in which it
travels.
3. A recording knife of the kind specified in Claim 1 having an axial cylindrical
bore b and conical end a¹ which is truncated by a section x-x' arranged at right
angles or approximately at right angles to the place of contact of the end of the
knife with the surface of the phonograph cylinder in such a manner that the section
surface at the place of contact with the cylinder has a short sharp cutting edge to
which there is connected on each side a scraping edge having an edge angle of
constantly increasing obtuseness, substantially as described with reference to
Figs. 1 and 2 of the drawings.
4. The modified construction of recording knife shown in Figs. 3 and 4 according
to which a cone-shaped knife a b c is formed at its base surface, which is arranged
next to the phonograph cylinder, with a conical hole a d b and is provided by
cutting the cone along a section 6 fe or bg extending through the lowest point b
of the section line a b of the two cones a b c and a d b, with a short sharp cutting
edge having a scraping surface connected thereto on both sides substantially as
described.