2. digital
  3. 140819-117192

A very good ENGINEERING explanation of why analog can not be as good as digital..

https://www.youtube.com/watch?v=lzRvSWPZQYk

There will still be some flat earthers who refuse to believe it....
Those should watch the video a second or third time :-)
128x128cakyol
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cleeds
5,764 posts
 
tom1000
There are no steps, no divisions, or resolution with analog, but there is with digital.
It’s a common misnomer that digital has "steps." To be fair, it seems intuitive that it does. But it doesn’t, as proven here. And analog has limited resolution, too - just as with digital.
There is no Nyquist theorem, which based on an approximation.
There most certainly is a Nyquist theorem. A fairly good explanation of it is here.

Please note that the Nyquist principle is a theorem, not a theory. That means it’s actually provable, using math and science.

I’m much more of an analog guy that a digital guy, but it’s important to understand how digital audio actually works if we hope to ever see it improved.
audioengr
3,282 posts
 
It’s a common misnomer that digital has "steps." To be fair, it seems intuitive that it does. But it doesn’t, as proven here. And analog has limited resolution, too - just as with digital.

It is certainly not proven with this youtube.  Digital is sampled, not continuous.  The reproduction accuracy with digital is a function of the sample-rate and filtering to "smooth" those steps.  Any NOS D/A chip will output these stair-steps and requires filtering to eliminate them.  If you disable or raise the frequency of the digital filtering from any Delta-Sigma D/A chip, it will have these stair-steps.  I have seen it on my scope.

There most certainly is a Nyquist theorem. A fairly good explanation of it is here.

The Nyquist theorem is true and often cited, however, it makes some assumptions such as the waveform is continuous and not transient.  Transient waveforms cause the Nyquist theorem to break-down.

Not that it doesn't apply, but the sample rate required to get an accurate transient reproduced is much higher that Nyquist would predict.

Steve N.

Empirical Audio

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cleeds
5,764 posts
 
audioengr

Digital is sampled, not continuous. The reproduction accuracy with digital is a function of the sample-rate and filtering to "smooth" those steps.

The Fourier Transform proves otherwise, and the transform really has more than one proof. One is in the video, but there's mathematical proof, too, if you really want to dive deep into it.

The Nyquist theorem is true and often cited, however, it makes some assumptions such as the waveform is continuous and not transient.
It relies on the Fourier math.

Transient waveforms cause the Nyquist theorem to break-down ... the sample rate required to get an accurate transient reproduced is much higher that Nyquist would predict.

If you could disprove the Nyquist Theorem, you'd be famous. It's already been proven. That's why it's a theorem.



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kijanki
4,413 posts
 
It is not matter of disproving, but rather knowing limitations (understanding it).  This theorem only states that you can recover continuous signal by sampling at least two times per period.  It does not say you can do that when waveform constantly changes.

cakyol's avatar
cakyol OP
940 posts
 
And to all vinylistas, who highlight the "shortcomings" of sampling, do you think that the small groove of a record is large enough to be able to store all frequencies from 20 - 20 khz, not to mention the relative intensities, ie the dynamic range.  You think all that information is FAITHFULLY written into 20 - 25 micro meters (typical width of a groove for 33rpm vinyl).  No way, since it is limited by PHYSICAL SPACE.

With digital, there is no limit, all you need is a bigger disk.  One can sample at higher frequencies as well as amplitudes.  The typical 16 bit deep CD can store 65k different ranges.  Increase that to 32 bits, and it will be 4 billion.

As I said before, I also DO like listening (I should say looking at) to vinyl but not because it sounds better but because it LOOKS better :-)


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