Evening star. [volume] (Washington, D.C.) 1854-1972, 1928-11-11
IDEA IN ACOUSTICS
A NEW
BY FREDERIC ]. HASKIN.

Solution of the problem of clear
speech in any large place of assembly
appears to be at hand in the shape OF a
device brought to perfection by Emile
Berliier, one of the eountry's noted IN
ventors.
For years the bane Of poor acoustics
has plagued both speakers and their
audiences. No matter how effective the
forensic artistry of an orator might be,
some auditoriums were totally tnSatis-
factory. It remained for Berliner. after
more than half a century of study OF
acoustics. to achieve the successful solu-
ton In the invention of what he has
designated the acoustic cement wall
cell.
Not only has the device proved its eff
fectiveness, but it has been accorded
scientific approval as we'll Installed In
the auditorium of the DreXel Institute
of Philadelphia, the invention accom-
plished tremendous improvement In a
hall which for more than a generation
was wholly unsuited for its purpose.
So impressed were the members OF
the faculty of the institute with the
Berliner device that DR.. ]. E. Schrader
of the physics department of the insti-
tuition declares that "it is not only re-
epoch in the acouStical field"
The statement from Drexel, reporting
on the tests to which the invention were
subjected, said that when work was first
started last year on improving the
acoustics of the hall, experts from all
over the country were called to Drexel
to inspect the auditorium and give sug-
gestions as to the best method to be
used. Notable among these was one of
the great teachers of the country and
an authority on sound.
Padded Walls Fail.
On his suggestion, Drexel authorities
followed the accepted principle of pad
ding the walls. but this proved thor
ough disappointment. When the next
call for experts was sounded Emile Ber-
liner came forward. Of practical test
OF his device the statement has this to
say:
THAT this has proved most salts
factory is atteSted by the. testimony of
these men who were seated in the
back rows of the auditorium Several
have said that they could hear per-
fectly and none has complained of be-
ing unable to hear. This is the first
time that this has been possible since
the construction of the auditorium.
Here is how Berliner arrived at the
conclusion which accounted for his
latest invention. He knew that wooden
walls have acoustic properties superior
to those with hard surface, but since
no fine building is so constructed, il
was necessary for suitable device to
overcome the defects of stone or other
hard surface which is customarily used
in the modern auditorium. 1t also was
necessary for the device to be un-
obtrusive so as to harmonic with any
type of wall finish. ......
In the course of his experiments
Berliner found that it was possible to
procure resonance in place of re-
verberation by forming hollow spaces
Immediately beneath the outer wall
surface. So he designed hollow cell
of wire mesh and covered this with a
porous cement, the latter being the
result of several years of experiment
The result was a device which produced
the effects of vibratory diaphragm that
prevented reverberation and actually
amplified the sound.
A Remarkable Career.
A word about Berliner's previous &C.
complishments, spread over more than
half century, will be an index to the
mans success in the inventive field
When the telephone of Alexander
Graham Bell reached the stage in its
early development where its limita-
tions hindered its further progress
Berliner came forward with the tele-
phone transmitter, employing the loose
contact principle which revolutionized
the whole field of sound transmission
by wire. This principle also was utilized
in the radio microphone, so that
Berliner, in fact, can be credited with
that device which is the very heart of
radio broadcasting. The continuous
current transformer, indispensable to
telephony and radio transmission, like
wise was his invention.
Let lis glance at the DEVELOPMENT of