On 12/29/2012 01:47 AM, Jörn Nettingsmeier wrote:
On 12/28/2012 03:50 PM, Chris Bannister wrote:
I am referring to the faithfulness of the reproduction, when
comparing analogue to digital. On paper, an analogue signal is an exact
reproduction whereas a digital signal is, by its very nature, an
approximation of the original, even if it is very close.
chris, i love my vinyls, but this argument is as old and tired as it
is wrong. any medium this side of the river jordan is band-limited, no
matter whether it's analog or digital.
This is true. And not also is it bandlimited, but also introduces
non-linearities
the evil little steps in a digital pcm stream are just an upper band
limit, and they are _low-pass_filtered_ on playback, which makes them
into a time- and value-continuous signal, i.e. analog.
if you think your lps give you some ultrasonic revelations, measure
again, and again after playing them ten more times. if the magic were
in the octave from 20-40khz, then every lp would be a disposable "use
once" medium. the frequencies below that are reproduced _perfectly_ by
a cd.
Playing the devil's advocate here..
Not true. There's also quantization error due to each sample being
represented as a discrete value from a set of 2^16 values in the case of
a CD. Shannon's sampling theorem requires afaict that the samples are
from the set of the real numbers.
http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem
http://en.wikipedia.org/wiki/Quantization_error
[...]
What makes digital systems so attractive is that both the bandwidth and
quantization error are easier to control than the typical limitations a
purely analogue system has. If your system has too little bandwidth then
increase the sampling frequency. If it has too much quantization noise,
increase the bit depth. A vinyl record and a physical record player have
so many hard to control limitations that it's just cheaper (much
cheaper) to get a sufficiently good reconstruction ability with a
digital system.. Needles have mass, they are non-rigid, the vinyl is
elastic, the speed of light is finite, etc. pp.. In the end a digital
playback system needs a D/A which is again an analogue system. But still
it's cheaper to get it good enough (testably) with a digital system and
a quality D/A than a purely analogue chain.
Have fun,
Flo
--
Florian Paul Schmidt
http://fps.io
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