Improvements in, and relating to, the Reproducing Diaphragms of Phonographs and similar Sound Recording and Reproducing Instruments.
Year: 1897

page_text: Date of Application, 29th Jan., 1897
Complete Specification Left, 27th Nov., 1897-Accepted, 1st Jan., 1898
Improvements in, and relating to, the Reproducing Diaphragms of
Phonographs and similar Sound Recording and Reproducing
Instruments.
I, THEODORE VAN HEEMSTEDE OBELT of 140 Rokin, Amsterdam, in the Kingdom
of Holland, Engineer, do hereby declare the nature of this invention to be as
follows:-
In phonographs and similar sound recording and reproducing instruments, it
is usual to provide a U shaped tube technically known as the way bar, one end of
which is blocked, while the other is open and connected by a flexible tube to the
are a number
speaker or reproducing diaphragm, and in the said tube
a duplex
of openings each adapted to receive the converging end of
flexible tube provided with attachments for insertion within the
SO
that
as
as
are
ear,
there
duplex tubes, may simul-
persons,
many
taneously listen to the reproduced sounds, Now it is well known that the persons
listening at the tubes farthest from the speaker or reproducing diaphragm do not
hear as distinctly as those at the tubes nearest thereto, and the object of my present
invention is to provide cheap and simple improvements in the said speakers or
reproducing diaphragms and the duplication of same, by the means of which the
reproduced sounds may be more evenly distributed over the whole of the said
Ushaped tubes or way bars, so that all listeners may hear alike, either through
the said flexible tubes, or resonators, or both.
My invention consists, Firstly of a method of and means for duplicating the said
diaphragm or speaker, so that this may be connected by flexible tubes to both ends
of the said U shaped tube or way bar, and, Secondly, of a method and means of
connecting the tympaniums of three or more diaphragms with that of a prime or
master diaphragin in connection with the recording surface, so that the sounds
reproduced may enter at three points into the said U shaped tube or way-bar, or
two into this, and one by means of a resonator.
For the purposes of the first portion of my invention I extend or elongate the
tube of the speaker or reproducing diaphragm, (to which the resonator or hearing
tubes are usually connected) and mount upon this a second diaphragm, the
tympaniums of the two said diaphragms being connected, centrally, by an adjust-
able taut wire or wires (which may or may not each be provided with a spring or
springs) so that the vibrations of the tympanium of the lower diaphragm, actuated
by its stylus being in contact with the recording surface, may impart absolutely
like and simultaneous vibrations to the tympanium of the upper diaphragm. The
said upper diaphragm may be provided with the usual extension or sound tube, to
which may be attached one end of a flexible tube, the opposite end of which may
be connected to one of the open ends of the said U shaped tube or way bar, (which
said way bar for the purpose of my invention would be open at both ends). From
the tube connecting the two said diaphragms, I provide a tubular extenion, to
which I attach one end of a second flexible tube, the opposite end of which may be

page_text: connected to the other open end of the said U shaped tube or way bar, and by
reason of the said wire connection between the tympaniums of the two said
diaphragms, sound vibrations, in accordance with the record, would be given off
from both diaphragms simultaneously, so that the sound waves by entering both
ends of the way bar would be distributed over the whole of its length and reach
all the listeners equally.
For the purposes of the second portion of my invention, I mount upon the sound
tube of a diaphragm, (the stylus of which is in connection with a recording surface)
a metallic or other vessel, in the form of an inverted cone or funnel, the mouth of
which is adapted to receive and hold two or more (preferably three) other or minor
diaphragms, the tympaniums of which are connected centrally by adjustably taut
wire or wires (which may or may not each be provided with a spring or springs)
with the centre of the tympanium of the first named major or master diaphragm,
so that the vibrations of the latter may impart absolutely like and simultaneous
vibrations to the tympaniums of all the minor diaphragms, the sound tubes of
which may be connected to flexible tubes in connection with the two ends and centre
of the before mentioned U shaped tube or way-bar, or two of the said minor
tympaniums may be so connected to the ends of the way bar, while the third may
carry a resonator, so that several persons may hear by the means of ear tubes con-
nected to, and at various parts of the said way-bar, while others may hear by
means of the said resonator.
I may find it convenient to provide means for connecting or combining the first
and second portion of my invention, so as to further extend or develope the principle
involved.
Improvements in and relating to the Reproducing Diaphragms of
Phonographs and similar Sound Recording and Reproducing
Instruments.
I, THEODORE VAN HEEMSTEDE OBELT of 140 Rokin, Amsterdam, in the Kingdom
of Holland, Engineer 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:-
In phonographs and similar sound recording and reproducing instruments it is
usual to provide a U shaped tube (technically known as the "way-bar") through
which the reproduced sounds are conveyed from the reproducing diaphragm to the
ears of the hearers, one end of which said way-bar is usually blocked, while the
other is open and connected by a flexible tube to the said speaker or reproducing
diaphragm, the said way-bar having a number of openings each adapted to receive
the converging ends of a duplex flexible-tube, provided for attachments for inser-
tion within the ears, so that as many persons as there are duplex tubes may simul-
taneously listen to the reproduced sound. Now it is well known that the persons
listening at the tubes farthest from the end of the way-bar connected to the speaker
or reproducing diaphragm, do not hear so distinctly as those at the tubes nearest
thereto, and the object of my present invention is to provide cheap and simple
improvements in such diaphragms, and in the duplication of same, by means of

page_text: which the reproduced sounds may be more evenly distributed over the said way-
bar so that all listeners may hear alike, either by the use of the said duplex flexible
tubes, or resonators or both.
My invention consists firstly of a method and means of duplicating the said
reproducing diaphragm or speaker, so that this may be connected to both ends
of the said way-bar. secondly of a method and means for connecting the tympanums
of three or more diaphragms with that of a prime or master diaphragm in con-
nection with the surface bearing the sound record, so that the sounds produced by
the vibrations of the tympanum of the master diaphragm, may be triplicated and
enter at three points into the said way-bar, or two into this and one into a suit-
able resonator.
In order that my invention and the means by which I purpose carrying the
same into effect, may be clearly understood, reference is hereinafter made to the
accompanying sheet of drawings of which
Fig 1 is a side elevation of an improved duplex diaphragm for conveying
reproduced sounds into both ends of the way-bar, after the manner illustrated by
Fig 2.
Fig 3 illustrates my improved method of connecting the tympanums of three
minor diaphragms, with the tympanum of one major or master diaphragm.
Fig 4 illustrates how the said three minor diaphragms may be enclosed within
a funnel shaped device to be mounted upon the first or major diaphragm (as shewn
by dotted outline in Fig 4) while Fig 5 illustrates how the sounds proceeding
from the said three minor diaphragms may be connected at three points with the
said way-bar.
For the purposes of the first portion of my invention, illustrated by Figs 1 and 2,
I extend or elongate the tube A of the speaker or reproducing diaphragm B (to
which the flexible sound-conveying tubes are usually connected) and mount upon
this a second diaphragm C the tympanums D and D₁ of B and C respectively
being connected, centrally, by an adjustable taut wire or wires E, which may be
in the form, of or have connected thereto, or otherwise be provided with, a spiral
or other spring, so that the vibrations of the tympanum D of B, actuated by its
stylus a, tracing the record in the cylindrical or other surface F, may impart
through E absolutely like and simultaneous vibrations to the tympanum D' of C.
The said upper diaphragm C may be provided with the usual sound tube or
extension b, to which may be attached one end of a flexible tube G, the opposite
end of which may be connected to one of the open ends of the U shaped way-bar H,
by the usual means (the said way-bar for the purposes of my invention being
open at both ends.
In the connecting tube A, I provide a tubular extension J, to which I attach
one end of a second flexible tube K, the opposite end of which may be connected
in like manner to the other open end of the way-bar H, substantially as shewn
at Fig 2, and by reason of the wire E uniting the tympanums D and D. it follows,
that sound vibrations, in accordance with the record upon F, would be given off
from both diaphragms simultaneously, that from B passing through K, and that
from C through G into both ends of the way bar H, and would be consequently
distributed evenly over the whole of its length, so that all the hearers whose duplex
flexible hearing tubes were connected to the usual openings e would all hear with
equal distinctness.
For the purposes of the second portion of my invention illustrated by Figs 3,
4, and 5, I mount upon the usual sound tube A of a recording diaphragm such
as L, (the stylus a of which is in contact with a surface upon which sound vibra-
tions have been recorded) a metallic or other vessel M in the form of an inverted
cone or funnel (shewn by dotted outline in Fig 3 and in plan at Fig 4) the upper
end or mouth of which is adapted to receive and hold two or more (preferably
three) other or minor diaphragms N, N1 N2, the tympanums of all of which are con-
nected centrally by adjustable taut wire or wires such as E, (each of which may be
in the form of, or have connected thereto, or otherwise be provided with a spiral

page_text: or other spring) with the centre of the tympanum D of the major or master
diaphragm L, so that the vibrations of the latter may impart absolutely like and
simultaneous vibiations to the tympanums of all the minor diaphragms N, N¹
and N, the sound tubes b¹, 63 and 63 of which may have connected thereto the one
ends of flexible tubes G1, G2, and G3, the opposite ends of which may be connected
in the usual way to the two ends, and at a central point d, of the way-bar H, as
illustrated at Fig 5, or in lieu of the tube G2 being connected as shewn to the
said way-bar, this may be connected to a resonator, while a second resonator may
(if desired) be mounted upon the point of connection d, so that several persons
may hear by the means of the usual duplex hearing tubes fixed upon the openings c
at various parts of the way-bar, while others may hear by means of the said
resonator.
my
I may find it convenient in order to further extend the principle of inven-
tion, to employ, in lieu of an ordinary diaphragm such as L, a duplex diaphragm
such as A, B, C, in connection with the arrangement illustrated by Figs 3, 4
and 5, and although I have herein described and shewn my invention as applied
to a phonograph in which a wax or other cylindrical surface is employed upon
which sound vibrations have been made, it is obvious that the principle of my
invention is equally applicable in connections with Graphophones and like instru-
ments in which the recording surface is in the form of a table or circular disc.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1st. In a phonograph, graphophone and similar instrument, for the reproduc-
tion of recorded sound vibrations, in which such sounds are conveyed from the
speaker or reproducing diaphragm to a U or other shaped way-bar, and from such
way-bar to the ears of the hearers, the construction, use and application of a
duplex diaphragm, and the duplication or triplication of minor diaphragms,
arranged to operate synchronously with a prime or major diaphragm, with means
for conveying such duplication or triplication of the sounds produced to two or
more points or parts of the said way-bar simultaneously connected, combined and
operating substantially as herein described and shewn by the accompanying draw-
ings, and for the purposes set forth.
2nd. In a phonograph, graphophone or the like having a cylindrical or other
shaped rotating surface such as F, upon which sound-wave vibrations have been
recorded, the combination of a duplex diaphragm, consisting of a diaphragm such
as B, with tympanum D, carrying a stylus a, in contact with a record surface F
the said diaphragm having an elongated hearing tube A, connected to a second
diaphragm C, having a hearing tube b, the tympanums D and I) of the said
diaphragms being connected by a taut spring or other wire such as E; a pair of
flexible tubes such as G and K, the one ends of which are in connection with b
of C, and a tubular extension J upon the said connecting tube A, while their
opposite ends are connected to the two ends of the way-bar H substantially as and
for the purposes herein described and shewn by Figs 1 to 2 of the accompanying
drawings.
3rd. In a phonograph, graphophone or the like having a cylindrical or other
shaped rotating surface such as E, upon which sound-wave vibrations have been
recorded, the combination of two or more minor diaphragms such as N, N' and Na
arranged and held within the mouth of a cone or funnel shaped metallic or other
case such as M, mounted upon the hearing tube A, of a prime or major diaphragm
such as L, the tympanum D of which carries a stylus a, in connection with the
record upon the surface F, the said tympanum D being connected by taut spring
or other wires such as E, with the tympanums of all the said manor diaphragms
the hearing tubes b, 61 and 62 of the said minor diaphragms having connected
thereto the one ends of a like number of flexible tubes such as G1, G2 and G3, the
opposite ends of two of which are connected to the two ends of the way-bar H

page_text: while that of the third is connected to H at a point d, or to a suitable resonator,
substantially as and for the purposes herein described and shewn by Figs 3, 4
and 5 of the accompanying drawings.
Dated this 20th dor of Novamhar 1807
GEO. THOS. HYDE,
1 Broad Street Bldgs London EC
Agent for the Applicant.