IMPROVEMENTS IN THE MEANS AND APPARATUS FOR CONVEYING SOUND TO IMENO DY TEL BAZIAN
Year: 1881

page_text: LETTERS PATENT to Charles Denton Abel, of No. 28, Southampton
Buildings, Chancery Lane, in the County of Middlesex, for an Invention
of "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR CONVEYING SOUND
TO IMENO DY TEL BAZIANIĆI
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 1st September 1881.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane, in
the County of Middlesex. "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR
CONVEYING SOUND TO A DISTANCE FROM THEATRES AND SUCH LIKE LOCALITIES
BY TELEPHONIC TRANSMISSION." [A communication from abroad by Clement Ader,
of Paris, France.]
This Invention relates to improved means and apparatus whereby vocal and
instrumental musical sounds, as well as dialogues or speeches that take place in
theatres and such like localities where the speaker or singer is apt to move about,
may be effectually transmitted by telephone to other localities so as to be distinctly
heard therein.
The perfect transmission of sounds from such localities meets with various
difficulties; thus the electric batteries employed in connection with the telephone
cannot maintain their intensity during an entire performance in a theatre, and
Such
they consequently require to be replaced from time to time by fresh ones.
replacing of the batteries however would produce unpleasant interruptions and
variations in the transmissions of the sounds. Again, if the transmitter of the
telephonic apparatus were situated at only one fixed point on the stage, the sounds
transmitted to the listeners at the distance receiving station would vary greatly
in distinctness, according as the actors or other persons moved about, so as to be
nearer to or farther from the transmitter.

page_text: The above inconveniences are, according to the present Invention, obviated by
the following arrangements:-The transmitting apparatus instead of being situated
at one single point of the stage is divided into two sets, of which one is situated on
the right hand side and the other on the left hand side of the stage, and one of
the receivers communicates with one transmitter of the one set, while the other
receiver is connected to a transmitter of the other set. By this arrangement the
listener at the distance station having one of the said receivers applied to each ear
hears sounds with the one ear differing in degree from those which he hears with
the other ear, and these variations of sound heard simultaneously by both ears
indicate to the listener the movements of the performer on the stage, the effect of
these different combined sounds upon the ears being somewhat similar to that
produced upon the eyes by the two different images in a stereoscope.
The arrangement and construction of apparatus which is employed for carrying
out the above described mode of transmission is as follows:-Assuming the
apparatus to be applied to the stage of a theatre there are arranged, either in front
of or behind the proscenium, two sets of transmitters, there being any desired
number in each set, situated at distances apart respectively on the one and on the
other side of the centre, and brought into action by electric batteries beneath the
stage or at any other convenient point; the electric currents being made to act in
the usual way on induction coils, from which the conducting wires are led to the
receivers of the subscribers at the distant station. Each transmitter has its own
battery, but it can be made to supply two or more subscribers.
In the arrangement employed, by preference, the one receiver of a subscriber is
connected to a transmitter of one of the before mentioned sets, while the other
receiver is connected to a transmitter of the other set. The receivers and trans-
mitters can be of any known construction, but with regard to the transmitters an
essential precaution must be observed. They must not be subjected to the shocks
or vibrations of the stage produced by walking or dancing, as these would interfere
very unpleasantly with the effective transmission. For this purpose each trans-
mitter is arranged in a box or casing, the botton of which is filled with a mass of
lead which deadens the vibrations, and the box itself rests upon its support by
means of caoutchouc blocks.
The transmitters, which are by preference microphonic transmitters, such as
those previously patented by my correspondent, are arranged horizontally along
-the-proscenium,-behind-or-in-front-of-the-footlights,_or_at_the_sides_of_the
prompter's box; if placed in front of the footlights they are placed in recesses in
the stage boards, covered by protecting gratings. If placed behind the footlights
they may also be arranged vertically against the parapet of the proscenium or
against the reflectors of the footlights, either above or below the stage boards.
r
As before stated, the battery serving to excite the coils of an individual trans-
mitter cannot remain in action during the four or five hours of a performance
without becoming polarised, and it must therefore be replaced by a fresh one after
a certain lapse of time. To enable this to be done without interfering with the
transmission, a distributing apparatus is connected to the batteries constructed and
arranged as follows:- -The distributing apparatus consists of a board, on which are
fixed two sets of spring blades facing each other, the one end of each blade being
fixed to the board while the other end is curved away from it so as to come in
contact with the corresponding end of the opposite blade, unless it is prevented
from doing so. There are as many such pairs of these springs as there are trans-
mitters, and there is one such distributing apparatus to each electric battery.
Between the two sets of spring blades of each apparatus is a sliding wooden bar
which can be pushed forward between the meeting ends of each pair so as to
separate them. The one spring of each pair communicates with the transmitter
to which it belongs, and the corresponding spring of all the other distributing
apparatus (which are all arranged in line with each other) is also connected,
while the other spring of each of the said pairs is connected with the one pole of

page_text: its respective battery, the other pole of which is connected to the coil of a trans-
mitter and to the couple of receivers in communication therewith. In operating,
all the sliding bars of the several apparatus, with the exception of one, are moved
so as to separate the pairs of springs, so that it is only the one battery of which
the distributor springs are in contact that furnishes the local inducing current.
After a certain lapse of time the sliding bar of another apparatus is moved so as
to bring its springs into contact, and thus bring another battery into action, the
bar of the first named apparatus being at the same time slid so as to separate its
springs and thus throw its battery out of action. As the changing of the batteries
produces a strong induced current in the coil, which current would result in an
unpleasant noise in the receivers, this is prevented by interpolating in the
conducting wires to the receivers a set of interrupting apparatus constructed and
operating in the same manner as the distributing apparatus above described.
The receivers are connected to the transmitters by a double line wire to prevent
the effects of induction.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Denton Abel in the Great Seal Patent Office on the
28th February 1882.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane, in
the County of Middlesex. "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR
CONVEYING SOUND TO A DISTANCE FROM THEATRES AND SUCH LIKE LOCALITIES
BY TELEPHONIC TRANSMISSION." A communication from abroad by Clement Ader;
of Paris, France.
This Invention relates to improved means and apparatus whereby vocal and
instrumental musical sounds, as well as dialogues or speeches that take place in
theatres and such like localities where the speaker or singer is apt to move about,
may be effectually transmitted by telephone to other localities, so as to be distinctly
heard therein.
The perfect transmission of sounds from such localities meets with various
difficulties; thus the electric batteries employed in connection with the telephone
cannot maintain their intensity during an entire performance in a theatre, and they
consequently require to be replaced from time to time by fresh ones. Such
replacing of the batteries however would produce unpleasant interruptions and
variations in the transmission of the sounds. Again, if the transmitter of the
telephonic apparatus were situated at only one fixed point on the stage, the sounds
transmitted to the listeners at the distant receiving station would vary greatly in
distinctness, according as the actors or other persons moved about, so as to be
nearer to or further from the transmitter.
The above inconveniences are according to the present Invention obviated by
the following arrangements. The transmitting apparatus, instead of being situated
,

page_text: at one single point of the stage, is divided into two sets, of which one is situated
on the right hand side and the other on the left hand side of the stage, and one of
the receivers communicates with one transmitter of the one set, while the other
receiver is connected to a transmitter of the other set. By this arrangement the
listener at the distant station having one of the said receivers applied to each ear,
hears sounds with the one ear differing in degree from those which he hears with
the other ear, and these variations of, sound heard simultaneously by both ears
indicate to the listener the movements of the performer on the stage, the effect of
these different combined sounds upon the ears being somewhat similar to that
produced upon the eyes by the two different images in a stereoscope.
The arrangement and construction of apparatus which is employed for carrying
out the above described mode of transmission is as follows:-Assuming the
apparatus to be applied to the stage of a theatre, there are arranged either in front
of or behind the proscenium two sets of transmitters, there being any desired
number in each set, situated at distances apart respectively on the one and on the
other side of the centre, and brought into action by electric batteries beneath the
stage, or at any other convenient point, the electric currents being made to act in
the usual way on induction coils, from which the conducting wires are led to the
receivers of the subscribers at the distant station. Each transmitter has its own
battery, but it can be made to supply two or more subscribers.
In the arrangement employed, by preference the one receiver of a subscriber is
connected to a transmitter of one of the before mentioned sets, while the other
receiver is connected to a transmitter of the other set. The receivers and transmitters
can be of any known construction, but with regard to the transmitters an essential
precaution must be observed. They must not be subjected to the shocks or
vibrations of the stage produced by walking or dancing, as these would interfere
very unpleasantly with the effective transmission. For this purpose each
transmitter is arranged in a box or casing, the bottom of which is filled with a
mass of lead which deadens the vibrations, and the box itself rests upon its
support by means of caoutchouc blocks.
The transmitters, which are by preference microphonic transmitters, such as
those previously patented by my correspondent, are arranged horizontally along
tlie proscenium, behind or in front of the foot lights, or at the sides of the
prompter's box; if placed in front of the foot lights they are placed in recesses
in the stage boards covered by protecting gratings. If placed behind the
foot lights they may also be arranged vertically against the parapet of the
proscenium or against the reflectors of the foot lights, either above or below the
stage.boards.
As before stated, the battery serving to excite the coils of an individual
transmitter cannot remain in action during the four or five hours of a performance
without becoming polarised, and it must therefore be replaced by a fresh one after
a certain lapse of time. To enable this to be done without interfering with the
transmission, a distributing apparatus is connected to the batteries, constructed
and arranged as follows:-The distributing apparatus consists of a board on
which are fixed two sets of spring blades facing each other, the one end of each
blade being fixed to the board, while the other end is curved away from it, so
as to come in contact with the corresponding end of the opposite blade unless
it is prevented from doing so. There are as many such pairs of these springs
as there are transmitters, and there is one such distributing apparatus to each
electric battery. Between the two sets of spring blades of each apparatus is a
sliding wooden bar, which can be pushed forward between the meeting ends of
each pair so as to separate them. The one spring of each pair communicates
with the transmitter to which it belongs, and the corresponding spring of all the
other distributing apparatus (which are all arranged in line with each other) is
also connected, while the other spring of each of the said pairs is connected with
the one pole of its respective battery, the other pole of which is connected to the
coil of a transmitter, and to the couple of receivers in communication therewith.

page_text: DESCRIPTION OF THE DRAWINGS.
'
Fig. 1 is a section, and Fig. 2, a plan shewing part of a theatre in telephonic
communication, as above described, with a house; T, T', are two sets of transmitters
connected to batteries P under the stage, and induction coils B, whence wires f, fi
lead to the pairs of receivers R, R¹; Fig. 3 shews to a larger scale, diagrammatically,.
the arrangement of these connections. Each transmitter has its own battery which
may serve for several subscribers, but the preferable arrangement is that shewn in
Fig. 2, according to which the one receiver R of each subscriber is connected with
a transmitter T of the one set, whilst the other receiver R¹ of the same.subscriber
is connected to a transmitter T¹ of the other set. Whatever be the form of the
transmitters and receivers, precautions are taken, as above stated, to keep the
transmitters free from shocks or vibrations, for which purpose the transmitters T,
as shewn in the section, Fig. 4, are arranged in a case A which is filled at its bottom
with a mass C of lead to deaden vibration, and rests on caoutchouc feet a, a. The
transmitters T may be arranged behind the footlights X, as shewn by the enlarged
section, Fig. 5, on each side of the prompter's box, or in front of the footlights, as
shewn in Fig. 5, in which case they are protected by gratings b. They may be
placed vertically, as shewn in Fig. 6, against the fence Y or reflector E. In
order to provide for a large number of transmitters, they may be grouped together,
as shewn in section at Fig. 7, and in plan at Fig. S. In this arrangement a long
opening S is formed in the stage behind the foot lights and covered by a grating,
and in a casing B under this opening are placed a number of transmitters, one
above the other, in pairs facing opposite ways. The box B may be hinged so that
it be opened downwards and can be hung to the stage floor by caoutchouc angles H.
To provide for bringing into use fresh batteries P, distributors D are employed,
one of which is shewn to an enlarged scale in front view at Fig. 9, in transverse
section at Fig. 10, and in plan at Fig. 11. On a board D are fixed a number of
pairs of spring blades c, c', a pair for each transmitter; between the two sets of
springs is introduced a bar of wood F, which when drawn forward separates all the
springs, but when pushed back allows each pair to come into contact. The bar F
is kept in the desired position by pins g passed through it and its guides G. It
will be seen in Fig. 3 that each of the upper springs c communicates with one polo
of a battery P, and each of the lower springs c with a transmitter T, the other
poles of the batteries being connected to the respective induction coils B. When
in use all the distributors D except one have their springs separated; after a time
the springs of this are separated by advancing its bar F, whilst those of one of the
other distributors are allowed to come into contact by retracting its bar. This
alteration is best done between acts; but as the strong currents induced by the
change produce disagreeable noises in the receivers, an interrupter I, shewn to an
an increased scale at Fig. 12, is interposed in the course of the wires f, f; this
interrupter is of substantially the same construction as the distributors D. In

page_text: order that any subscriber may lock up a number of telephonic connections, the
arrangement of box may be adopted, such as is shewn in transverse section at
Fig. 13, in sectional plan at Fig. 14, and in front view with the lid removed
at Fig. 15. In this box there are as many springs R, R¹, &c., as there are
telephonic lines, each bearing against an angle piece C, C¹, &c., which is connected
in the same line as R. On the lid L of the box is a bar I, which when the lid is
closed presses back all the springs R, R¹, &c., thus breaking contact with all the
pieces C, C¹, &c.
Having thus described the nature of this Invention, and in what manner
the same is to be performed, as communicated to me by my foreign correspondent,
I claim in respect of a system of telephonic communication from a theatre or other
similar establishment to auditors at a distance,-
First. Arranging the transmitters along the front of the stage so as to command
the various positions of the speakers or singers, substantially as herein described.
Second. Deadening shocks and vibrations by loading the casings for the
transmitters with lead, and resting them on caoutchouc.
Third. Arranging the transmitters in two sets, one of each set connected to one
of a pair of receivers, one for each ear of a subscriber, as and for the purpose herein
set forth.
Fourth. The construction, substantially as herein described, of distributors D for
bringing successive batteries into use.
Fifth. The method, substantially as herein described, of stopping the telephonic
communication, as by the interrupter I when batteries are changed, or by the
arrangement described with reference to Figs. 13, 14, and 15, when auditors are to
be excluded. .
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and seal, this Twenty-eighth day of February, in the year of our Lord
One thousand eight hundred and eighty two.
CHA. D. ABEL. (L.S.)