One Bit of Information About New Audio
by Jim Bray
The technically challenged among us may not know about 16 bit, 20
bit, 24 bit and all the other nifty and confusing audio bits, bytes, and
samples that have been involved in the audio industry for the past twenty
years, but despite that these computer terms have had a fundamental impact on
the way we listen to music.
And now theres another technology on tap that actually takes
digital audio to its most fundamental basics.
Well, kind of, anyway. Its called one-bit technology, which
at least so far is mostly used in high-end audio systems and home theaters -
though that may be about to change.
One-bit technology is supposed to combine the best of old
fashioned analogue we knew from the vinyl record and cassette tape days
(i.e., its fidelity to the original sound source) with digital
technologys virtually degradation-free transmission process.
Heres how it works, in a non-technical nutshell:
The PCM (Pulse Code Modulation) technology of old
style CD's records and reproduces audio frequencies from 20Hz up to
20kHz, which is approximately the audible range for humans. But the human ear
can actually perceive sounds above 20kHz (depending on how much Rock and Roll
has been listened to over the years!), and its said that some sounds in
the natural world around us can reach of up to 100kHz. This is why dogs hear
sounds we dont: their ears have a different frequency range than
And human children seem to have a hearing range much less than
their parents, judging by how they act when spoken to by those parents. Oh
wait, that isnt a hearing range, its a listening range
You would think with the way kids act today that they need a hearing aid, but their behavior is more selective hearing than anything else.
But I digress
One-bit audio is theoretically capable of achieving a frequency
response of 0 to 100,000 hertz with a dynamic range (the ratio between the
quietest and the loudest sounds a piece of equipment can reproduce) of 120
decibels. This is said to allow for the faithful reproduction of, for example,
the ca-ching of a high hat cymbal, while the broader dynamic range
can capture a full orchestra in all its glory.
To record and reproduce this full range of sounds, one-bit
technology samples (takes a digital picture of) the
original signal at what almost seems an unbelievable frequency: 2,822,400 times
per second (2.8224MHz). Thats even faster than the sampling that goes on
in the food section at Costco at lunchtime on a Saturday! In fact, its 64
times faster than a PCM CDs sampling rate of 44.1kHz.
The other major factor in one-bits supposed superiority is
its ability to eliminate signal deterioration, which means the sound stays true
from recording right through playback in your home - theoretically of course.
It does this by calculating only the differences between the samples, in effect
comparing one sample with the next and ignoring the parts that dont
change. This is kind of similar to how DVDs work: storage space is
optimized by eliminating redundant information between one video frame and the
Sharp Electronics, among others, is bullish on one-bit technology,
claiming that it finally realizes the dream of completely authentic sound
reproduction. Okay, weve heard that before (I remember being told the
same thing when the audio compact disc was introduced and perhaps before
that with half speed master recordings in the old vinyl days) but,
despite the hype, one-bit audio technology sounds pretty nifty.
Then again, a friend of mine who co-owns a local high end audio
store isnt impressed, and I respect this persons knowledge, so best
to let your ears be the judge.
One bit goes beyond merely being a new recording medium: its
opening up new markets for digital amplifiers as well as disc players. So if it
lives up to its potential (and, as Ive said, this is still a big
if) it could help breathe new wind into your home audio
Time will tell, of course.
When applied to an amplifier, one bit technology can allow for a
smaller footprint than traditional amps (which means it takes up less space),
as well as supposedly being more energy efficient.
How much smaller and more efficient? When compared to a
conventional amplifier of equivalent power output, a 1-bit amplifier only uses
about half the energy and only radiates about a fifth as much heat. This allows
a 1-bit amplifier to shrink to about a third the size of a conventional
The downside is that your customers will no longer be able to
toast marshmallows over their amps heat sinks!
Not surprisingly, early examples of one-bit technology tended to
be high end and priced accordingly. Super Audio CD players, which use one bit
technology, were anything but mainstream until recently as were one-bit amps.
This may be changing.
Sharp Electronics, for example, has introduced a couple of
interesting one-bit products, including the all in one SD-AT100,
which not only has a 5.1 channel one-bit amplifier but which also includes a
built-in DVD-CD, digital tuner and comes with a speakers. This system sells for
about $1500, which is a pretty mainstream price considering the technology.
Unfortunately, it doesnt play SACD or DVD-Audio discs, which seems to
defeat the purpose somewhat.
So is one-bit audio the Next Big Thing? Who knows? I havent
even heard it yet (though Ive heard SACD played back beautifully on a
high end, conventional audio system), so cant judge fairly how much is
hype and how much is hope.
But its always nice to have choices. So if nothing else,
one-bit audio is a welcome player.
Jim Bray's technology columns are distributed by the TechnoFILE Syndicate. Copyright Jim Bray.
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