The Morning Tulsa daily world. [volume] (Tulsa, Okla.) 1919-1927, 1921-11-13
VOICE IS HEARD
FOR FOUR MILES
Installation in Catskill
Mountains Breaks All
Known Records

what Ia undoubtedly the loudest
reprcductlon OF the human. voice on
record was attained during dem-
onstration OF "A powerful loud
speaker" recently made I'm the Cat
skill mountains.
This loud speaker is designed prl-
marlly for addressing very large
public gatherings. IT is more pow
erful but otherwise very similar. to
the loud" speaker" which President
Harding used In his inaugural ad-
dress 1t which his voice was heard
with the greatest ease by a crowd OF
l25,Uu0 persons, some OF whom
stood 700 feet from the speakers
stand.
The installation at Napanoch in
the Catskllls projected the voice 3.s
miles and simple computation
shows that In the sector of this
radius around the "loud speaker"
the entire population OF the United
States could be placed without un-
comfortable crowding. The demon
stration showed that speaker
standing in front Of the telephone
transmitter, which ordinarily forms
a part ot the loud speaker" could
have his voice projected over this
great area, and also proved that the
same magnification could be given
the voice Of a speaker 900 miles
away when he talked over a long
distance telephone line connected
directly to the ampliflcr of the de-
vice. The loud speaker" in the
Catskills was connected to the Bell
long distance telephone circuit to
Chicago, and the words spoken into
the ordinary telephone transmitter
IN Chicago were clearly heard over
this enormous area.
The loud speaker includes a tele-
phone transmitter. an amplifier, and
several large wooden horns or
sound projectors supported by a
low steel tower. Each protector Is
equipped at its small end with a
very powerful telephone receiver for
converting into sound waves the
variable electric currents supplied
IL The purpose of the amplifier is
to magnify the vary minute currents
produced by the transmitter. which
are then led to the receivers.
The apparatus is the product Of
the research laboratory maintained
Dy the Bell Telephone system, In
ms laboratory. which liz the largest
devoted to the application Of science
10 human affairs, $500 persons are
employed, and exhaustive studies OF
every technical question arising In
lhe telephone art are made. 1t con-
hututes one of the very important
agencies OF the Bell system, to de-
'''Op the art OF telephony. and main
lain Americas supremacy In speech
communication.
The projecting OF the human voice
over the remarkable distance of
nearly four miles was an accom-
pHshment resulting from exact and
E4'hs'ak'nE scientific development.
mere was first required telephone
uansmltier so perfect In its opera
lion that It reproduced with abso-
llte fidelity the complicated waves
OF the human voice In the form of
electrical currents. In the second
p'act' an amplifier was required
winch would magnify with equal ac.
cuIaey the minute currents Gener-
ated by the transmitter Finally,
lhe ibrgc telephone receivers at
taehed to the sound projectors are
ol such skillful design that they re-
convert the magnlfied electrical cur
rents In sound waves without the
slshtest distortion. In order that
me sound waves produced by the
p'"Je''oTS should be heard across
.he .he valley nearly four miles away,
ne amplfier magnified the cleo
lrleal energy received from the tcle-
panone transmittcr about 10000, 00O,-
WV times. and this ten billion fold
dampI'iication was produced without
~ any way destroying or distorting
.he original quality Of the speak
erP voice.
me loud speaker involves appa-
'alus which is exactly similar In prin-
Ape 10 the equipment OF every long
Instance telephone line. Every Ions
Instance telephone circuit Involves.
uimonF many other things, a trans
asS'tr' an amplifier and receiver,
ana the successful design and main
.ennn'e 5 Of such circuits was neces-
,tly preceded by very far reaching
studies OF all the clements comprls-
bhs lie circuit The loud speaker Is,
,he 'ylore' natural by-product OF
,a I'Srarcnes underlying long dis