IMPROVEMENTS IN APPARATUS FOR THE TRANSMISSION, AND RECEPTION OF SOUNDS.
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by William Chase Barney at the Office
of the Commissioners of Patents on, the 13th' January 1882.
WILLIAM CHASE BARNEY of 53 Bernard Street in the County of Middlesex,
Gentleman. IMPROVEMENTS IN APPARATUS FOR THE TRANSMISSION, AND RECEPTION
OF SOUNDS.
.
When the microphone or current regulator for transmitting sounds is attached
to a thin plate of any material, or is so placed in relation to such a plate that
vibratory motions given to the plate will impart to the microphone or current
regulator corresponding vibratory motions the articulation of words spoken
to it is rendered indistinct at the receiving end. The larger the plate the greater
will be the vibratory motions and hence the more indistinct will be the articulation.
The effect of sound waves upon a vibratory plate is similar to that of the impact
of stones upon a smooth surface of water, when thrown upon it in rapid succession.
The first stone upon striking the water causes a series of circles proceeding from the
point of impact constantly increasing in circumference and diminishing in height.
Each following stone produces a like effect, and these several series of circles confound
with each other and instead of a single series of uniform circles, there is a confusion
of undulations of the water. In like manner, when a series of sound waves falls
upon a plate, easily made to vibrate, the first wave gives to the plate a vibratory
motion, and succeeding sound waves falling upon the plate at different angles and
striking it at different parts produce each its own vibratory motion and thus there
must be occasioned a confusion of vibratory movements of the plate which are
necessarily communicated to the microphone. Hence the undulations of the current
do not correspond to the action of the sound waves only, but the regularity of those
undulations are greatly interfered with by the irregular vibratory movements of the
microphone, and therefore the articulation is rendered more or less indistinct as the
plate is more or less easily made to vibrate.
In order to protect as much as possible a microphone or current regulator from
the evil necessarily attendant upon the use of a thin vibratory plate in connection
therewith, I place my microphones inside a box made of wood, cork, ebonite, felt,,
or any equivalent material, the material surrounding the microphone being of
sufficient thickness to reduce to a minimum any vibratory movements which the

page_text: sound waves may give to the material, thus leaving the microphone to be acted
upon by the molecular movement of the material to which it is attached. This box
is not fixed to any substance but merely rests on the top of a box containing the
induction coil, where it is retained by its vis-inertid.
In my first form of improved microphone, instead of having the contacts of the
two carbon terminals made by the movement of a tympan, to which is attached one
of the terminals of the battery or of the induction coil, and by which movement
contact is made with the carbon terminal of the other pole of the battery or of the
induction coil; in my system the carbons to which the two terminals of the battery
or of the induction coil are fastened, connect with the same material, and the vibration
of the air occasioned by the movements of the diaphragm cause a movement of the
carbon. Two flat pieces of carbon separated from each other are attached to a block
of any non-conducting material, each of said pieces being connected to the induction
coil or battery, and a piece of carbon lying upon both pieces of carbon which is
held in its place by two pins of carbon which are placed in holes in the flat pieces
of carbon, either fixed or movable, so that [the electric circuit is completed by the
contact of the upper piece through the lower pieces.
Another form of microphone I construct in the following manner:-Two blocks
of carbon or other equivalent material, which prefer to make so as to present a
surface of at least an inch square are each connected to one of the terminals from
the induction coil or battery. One of these carbons is placed on the inside at the
bottom of a box filled with powdered carbon and the other inside on the top or lid
of the box which top or lid may be of some thin vibratory non-conducting substance.
The bottom of the box may be of the same vibratory material or more solid. The
box must be composed of some non-conducting material and the powdered carbon
should not be very fine but crushed and sifted so as to reject the fine powder which
is liable to cake.
-I further improve both the above described microphones by making a multiple
microphone of one or the other by connecting together for quantity two or more of
the same microphones.