Popular Science - USA (2019-10)

(Antfer) #1

14 WINTER 2019 • POPSCI.COM by Eleanor Cummins / illustration by James Gilleard


MAKING NOISE IS EASY,
but saving it is hard. Humanity’s
first big innovation in file sharing
came along around 3,400 years ago,
when ancient Mesopotamians
experimented with a written nota-
tion for melodies they’d previously
only shared out loud. It wasn’t until
the mid-19th century that engineers
began to capture the sound waves
themselves. The quality of early
devices was low—poor materials
and grimy recording environments
could make music turn ghostly.
But technicians continued to refine
their tools; now anyone with a smart-
phone can save high- quality audio.
Next time you blast your person-
alized playlist, remember to thank
these musty old machines.


TURN BACK TIME

play it again


Compact disc
Philips and Sony both created
versions of the CD, which hit stores
in 1982. Technicians would place a
glass master disc under a laser that
spun according to a digitized audio
signal—a mathe mati cally simpli-
fied version of sound. The short
wavelength was great for writing
small, allowing lots of data in a con-
fined space. By the mid-1990s, any
computer could burn CDs.

Phonautograph
In 1853, Édouard-Léon Scott de
Martinville invented the phon auto-
graph and made the likely first copy
of a human voice seven years later.
The device’s stylus preserved sound
waves by etching their movement
into smoke- darkened glass, but
Scott never managed to create a
machine that could play back the re-
sults. No one would hear his snippet
of “Au Clair de la Lune” until 2012.

Magnetic tape
German engineer Fritz Pfleumer
created magnetic tape—the pre-
cursor to cassettes—in 1928. As a
strip of film coated in iron oxide ran
through an electromagnetic field,
incoming sounds would alter the
arrangement of particles and leave
behind a magnetized signature. The
device could just as easily convert
these recordings back into an elec-
trical signal and play the tape aloud.

Wax cylinder
Thomas Edison invented a replay-
capable phonograph in 1877, but
it took Alexander Graham Bell
nine years to turn that concept
into the commercially available
Graphophone. Audio entered a horn
and vibrated a diaphragm, which
pushed a stylus into wax to cut
grooves. To produce the tones, the
needle followed the transcription
and pushed audio back through.

MP
We’ve mastered recording audio,
but storage has room to improve. In
1993, Germany’s Fraunhofer Insti-
tute published the first MPEG audio
standards. This format’s lossy com-
pression algorithm shrinks a file by
90 percent without a drastic drop in
sound quality. More-recent versions
avoid loss entirely, but engineers are
working to make the tech cheaper,
easier, and faster to use.

1860


1993 1982


1886


1928

Free download pdf