By Al Fasoldt
Copyright © 1989, The Syracuse Newspapers
When the transmission fell out of my 180,000-mile Camry a few
weeks ago, I suddenly lost my wits and took a few test drives
in new cars.
It was a sobering experience. The stickers on the windows reminded
me that replacement transmissions, even fancy electronically actuated
Japanese ones, are cheaper than new cars. And the dashboards reminded
me of the last remaining problem of digital sound.
If the connection between high-tech new cars and high-annoyance
digital audio seems unclear, let me tell you what I saw in the
windshield of one of the cars I drove.
I saw two numbers suspended in space out in front of the car,
in a sort of hologram. They were supposed to show me how fast
I was going.
This was a "heads-up" display. The theory is that if
you're able to see how fast you are going in numbers projected
out in front of you, you won't have to look down at the instrument
panel. Drivers can keep their heads up.
Not me. I kept looking down at the dashboard, desperate for a
"real" speedometer—the kind with a dial and a pointer.
I wanted an analog display, not a set of digits.
The problem with digital representation of speed or time is that
you get no sense of continuous movement. I saw "47"
out in front of me and then suddenly I saw "51." Did
the car jump through hyperspace to go instantly from 47 mph to
51 mph?
Digital clocks cause a similar warping of reality. As I look down
at my K mart pen-watch, it says the time is 9:36. It keeps saying
that for quite a while. Then it changes its mind and says it's
9:37.
But my old-fashioned Timex tells me the truth. Three pointers
move around the dial at different speeds. I can see at a glance
that while two of the pointers seem to show that it is 9:36, the
third one tells the real story:
Time is always flowing, moving from one second to the next-one
nanosecond to the next, one infinitely short moment to the next.
Sound works the same way. Anything we hear is a continuous event
that starts at one time and ends at another. Whether it's thunder
or the Beatles wanting to hold our hands, sound isn't a bunch
of on-again, off-again states like heads-up speedometers or digital
watches. It's a constant flow of audible information.
Audio engineers know this, but they also know that the magic word
in hi-fi these days is "digital." So instead of bringing
back analog sound-in which the recording is a continuous wiggle
in a groove, corresponding exactly to the sound that the microphones
picked up-audio engineers are now trying another approach. They're
making digital sound behave as if it were analog.
Components that handle this best-of-all-possible-worlds task were
demonstrated at the Summer Consumer Electronics Show in Chicago.
Two different ways of doing this were shown.
The first method relies on a mathematical cold shower. The latest
compact disc players treat the digital signal to a bracing wake-up
spray in the form of new calculations as the signal goes through
the player.
The parts of the signal that represent the quietest sounds—where
digital recordings have the greatest trouble being accurate—are
shifted around so that the faintest whispers on the master tape
come through almost as if they started out in analog form.
The second method uses a machinegun approach. The digits—called
bits in both computer and audio terminology—are routed around
the standard circuits and fired one after the other in a rapid
stream. This "bit stream" is aimed at a conversion circuit
that turns the pelting of all these bits into sound.
"Bitstream" technology could become the standard way
of decoding digital recordings, some industry experts say. The
sound it creates is excellent and it has a further advantage:
It's cheap.
Other refinements are sure to come as engineers and circuit designers
learn how to smooth the rough edges of digital sound. And each
new development is likely to spur on a few more, as companies
here and in Japan compete for a share of the market.
Unfortunately, progress in audio isn't likely to lead to a change
in the auto industry, where digital speedometers are appearing
on more and more cars.
Maybe the designers in Detroit and Tokyo need a few pointers themselves—the
kind that move around a dial, the good old-fashioned way—before
they get the message.
technofile:
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