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By
Michael J. Himowitz
Baltimore Sun
When
George W. Bush accused Al Gore of "analog thinking in a
digital age," it made a great sound bite - or should I say,
sound byte.
While no one has ever accused "Dubya" of being a wired guy,
it's obvious that he'd never bothered to look up the meaning
of the verbiage he tossed out at a campaign stop in Michigan.
Otherwise, he might have known that he was attacking Gore
for thinking like a human, as opposed to a machine.
Don't be too hard on George, though. He's not the only one
guilty of misapplication of technobabble. Plenty of people
toss out the words "analog" and "digital" these days without
thinking about what they mean. I do it all the time - I
even get paid for it.
Which brings me to a couple of notes I've received from
readers who complain that I'm always using terms such as
"digital photography" or "analog recordings" without explaining
what they mean, or why the terms digital and analog are
so important.
So here we go. The term analog has the same root as the
word "analogy," which refers to a similarity in some respects
between things that are otherwise different. Drawing analogies
is one of the keys to human thought. It's at the heart of
our ability to apply past experience to future behavior.
We prize this talent - just ask any high school student
who has sweated through the analogies section of the College
Board exams.
In the world of science and technology, an analog device
is one that attempts to directly reproduce some kind of
infinitely variable physical process in another medium.
That's a mouthful, and it's best explained by example. When
I sing in the shower (an ugly thought), my vocal cords set
up vibrations in the air that we call sound waves. If you're
within earshot, your eardrums pick up these vibrations and
pass them to your brain, which processes them into my rendition
of "Stairway to Heaven."
In any case, sound is infinitely variable, which is why
Mariah Carey, Luciano Pavarotti, Nine Inch Nails and Mike
Himowitz sound so different.
When Thomas Edison invented the phonograph, he was looking
for a way to capture a moving picture of these invisible
sound waves. He did it by attaching a needle to a diaphragm
at the end of a reverse megaphone. When sound waves struck
the diaphragm, they caused it to vibrate, and Edison recorded
those vibrations on a sheet of tinfoil wrapped around a
rotating cylinder.
If you put the tracks the needle made under a magnifying
glass, you'd see patterns and variations that were directly
analogous to the shape of the sound waves that created them.
Passing another needle over those tracks, this one attached
to the diaphragm of a crude speaker, created sound waves
that reproduced the original - sort of.
The "sort of" led to a century of improvement in recording
technology. Edison's cylinders were replaced by vinyl discs
and later by tape, which used tiny fluctuations in magnetic
fields to record the shape of the sound waves. But the principle
remained the same. In fact, there's nothing inherently wrong
with an analog recording - by the late 1960s engineers could
reproduce sound brilliantly.
The problem with analog recordings is that they're not permanent.
The very act of playing a vinyl record causes minute changes
in the grooves that represent the sound waves. The same
degradation happens to a tape when it passes over the magnetic
play head of a cassette deck. By the 100th time you play
an analog recording, it won't sound nearly as good as it
did the first. Worse yet, the original recording is subject
to the same kind of degradation over time.
By the late 1970s, engineers had developed methods to use
digital devices to record and play sound. Their problem
was that computers are composed of millions of tiny switches
that have only two logical states - on and off. Using analog
reasoning, we think of those states in terms of two numbers,
one and zero. Computer scientists group these binary digits
into strings of eight numbers called bytes, which is how
data are stored in memory chips.
To approximate the infinite variation of sound as a series
of ones and zeros, scientists hit upon a scheme called "sampling."
This involves taking a "snapshot" of the sound at frequent
intervals and recording each as a number. The question is
how often you have to sample and how big a number you need
to record all the possible variations in sound that our
ears can discern.
By sampling sound 44,000 times per second, and using 2 bytes
of data for each sample, engineers found they could reproduce
a speech or concert that sounded realistic to our analog
ears.
More importantly, the system divorced voice and music from
its medium. Analog recordings were bound to the studio's
master records and tapes, but digital music could be stored
anywhere. As long as they could recall the numbers, engineers
could reproduce a symphony down to the last "ding" of the
triangle. All they needed was the right hardware and software.
We have that software and hardware today. That's why we
can store music files on our PCs, transfer them to CDs or
trade them on the Internet. Each one is a perfect reproduction
of the original recording.
Using the same principle, we can snap a digital photograph
that chops an image up into tiny dots, each one of which
is represented by a number that represents its brightness
and color.
Just remember that at its best, a digital recording is only
an approximation. That's why the best recordings never sound
quite like the real thing. Our brains - the most complex
machines on Earth - are analog devices that perceive an
infinite number of shades, sounds and colors and make leaps
of logic and intuition that computers will never match.
George W. notwithstanding, next time somebody accuses you
of being an "analog" thinker, take it as a compliment.
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