> "The ultimate goal of digital, is to replicate analog." Isn't
> that
> ironic?? CD's goals are to sound like an analog signal, and
> digital
> picture's goals are to look like an analog picture. So if I
> have analog
> already, why do I want digital??
To what level of detail? This is the question that might be
relevent in many analog/digital questions. In audio, CDs are
recorded with a sampling rate of 44,100 samples (voltage
measurements) per second. That voltage measurement is then
recorded in 65,536 possible readings (2 bytes per sample). This
is for "uncompressed CD audio".
CD audio is only really effective at creating an adequate square
wave at about 4 or 5khz. Important? Somewhat, but a
well-designed analog recording studio is able to pass square
waves beyond the range of human hearing. However, most important
to the texture of sound (and three-dimensionality) is timing
resolution. Timing resolution means that a particular waveform
structure will be moved backwards or forwards a sample. This
screws up the arrival times to the human ear. Good old vinyl
records may not have had the greatest signal-to-noise ratio nor
recorded frequency response, but it had near infinite timing
resolution.
In an A-B comparision test of a recording of an orchestra (given
proper miking techniques) and a supurb playback environment (or
quality headphones), you can identify the phantom locations of
various string sections with digital. With analog (or very high
sampling rates such as 96k or 88.2k) you can locate individual
instruments.
That's with audio. MPEG compression is a lossy compression
which moves some sounds around, eliminates others and reduces
the bit depth (meaning it alters the voltage measurement) of
anything it can. To the average ear, digital-tv (cable,
direct-tv satellite, and the horror--DVD) sounds great. To the
masses, even MP3s rock. To most of us audio pros, it sounds
like fingernails on chalkboard. I'd rather not defend my
credentials on this, but I've forgotten more about the
compression algorithms than I ever really wanted to know.
Unfortunately, it's a fixation thing: once you hear/see the
flaw, that's all you hear/see. After a couple of minutes it can
become unbearable. About as uncomfortable as sitting through an
entire Kevin Cosner film with a full bladder.
Digital imaging and audio have undergone similar paths, with
imaging following audio by 20 years. In audio we started out
with lossless data storage. Now nearly everything outside of
the recording masters is subject to lossy compression of lower
and lower standards. It's a gradual dumbing down of the ears.
We've been dumbing down the eyes for 50 years. Kodak did the
world a huge disservice with the 110 and disk-film cameras.
Pictures were so soft and grainy as to be unbearable to view by
those of us who need to see things a little sharper. It
conditioned the masses for single-use cameras and digital
garbage pits.
Analog remains the most efficient storage and transmittion
system. We seem to be coming full-circle in some areas.
Believe it or not, but manufacturers are developing new
fiber-optic systems that don't use pulses of light, but vary the
light level and color. Hmm. Sounds analog to me. Something
about being able to transmit up to 8x more data than with
digital.
In audio, the primary advantage of digital is signal-to-noise
ratio and repeatability. In editing, there is no comparision
either. I'll take digital editing anyday! Again, don't get me
started on that subject.
In imaging, the primary advantage of digital is near-instant use
and output of the images. S/N of digital isn't as good as
analog. Frequency response (color response) isn't as good or
selectable as analog. Storage and retrieval of digital images
is awful as compared to analog (I can shuffle though 2,000
trannies on a light-table faster than you can find and view less
than 10 on the computer. Editing? Sure, digital beats analog
there--unless you are a B&W darkroom junkie, like me, where the
bitdepth just isn't sufficient.
OM-Content: Nothing is sweeter than the sound of an OM's
shutter as it completes a 2-minute auto exposure.
AG-Schnozz
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