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Interesting Video on Analog vs. Digital - Page 2

post #16 of 41
2/25/10 at 11:25am
Thread Starter 
Quote:
Originally Posted by Dr. Strangelove View Post
If we are talking about qualitative differences between 16/44.1 and higher bitrates/frequency, then what one sees (or more accurately hears) doesn't matter. To find the difference between the two, they must be the only variables in the proverbial system. What you perceive as sound is a variable, and therefore taints a test. Only methods that involve the use of extremely low variable measuring entities and sound creation entities with the only large variable being the res of sound used will show what the difference really is. Also note that there is more than just one category of difference between redbook and higher res.
It's actually my recording experience that informs my view on hirez digital. We run an identical recording box in 16/44.1 and 24/176 straight off a split mic feed. So I can hear both redbook and hirez with the only variable being the change in word length and sampling rate. There is much more air around the instruments and better timbre on the hirez recording. It doesn't matter if we do jazz, Irish folk, classical strings, orchestral, or choral.

We have tested this with headphones right into the Sound Devices amp, by our mastering computer with high end sound card once the digital file is transfered, and with unedited DVD-Audio and CDs from the raw recording file.

So you have the same mic placement, same mic cable, same mic preamp, same converters, same playback system.

The difference is not subtle...whether we use a $170 Oppo 980H or a Oppo BD83 or several multi-kilobuck DACs.
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post #17 of 41
2/25/10 at 11:33am
Thread Starter 
Quote:
Originally Posted by Ham Sandwich View Post
Even if we're to accept that high resolution audio is better than CD, that doesn't mean that the CD format isn't adequate for reproducing the subtleties and ambiance that both videos claim goes missing when recording digitally. I've heard CDs with space and ambiance so I know CDs can do it.
I agree that really well mastered CD can have lots of ambience so I don't really take the content of the video to be 100% accurate (it is directionally correct). However, hirez does ambience much better. Things like instrument reverb off a studio wall, decay and sustain of notes...all best done in hirez.
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post #18 of 41
2/25/10 at 2:07pm
Quote:
Originally Posted by haloxt View Post
Redbook cd does lose information by being 44,100hz even if it is later smoothed out by a filter.
That's beside the point that I was making, which is irrespective of sampling rate.

The portion of the video I was addressing wasn't saying that information is lost because of inadequate sampling rate. It was saying information is being lost because of sampling itself.

se
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post #19 of 41
2/28/10 at 3:11pm
Quote:
Originally Posted by Koyaan I. Sqatsi View Post
It would be funny if it wasn't so sad.

The digital-as-stair-step is the oldest propaganda myth in the book.

From the video:

In analogue, sound is converted into analogous electrical waves.



In digital, instead of a continuous wave, you get samples of the wave. 44,100 samples per second.



So by definition, when you listen to digitized music, you're not hearing all the music, just slices of it.

By definition, the producers of this video are glaringly ignorant and haven't a clue what they're talking about.

What they fail to mention is that stair-step nature of the waveform represents frequencies at and above the sampling rate, i.e. 44,100 Hz in the case of Compact Disc.

In other words, the depiction shown is the signal PLUS the frequency components of the sampling rate.

Most every playback system uses what's called a "reconstruction filter" which filters out frequencies at and above the sampling rate.

Once they're removed, what you get is this:



A continuous waveform.

se
Fascinating images, Those jaggies look nasty. Do they exist at a 44.1 khz frequency? Hence the need to roll-off at 22khz so we do not hear these jaggies? What off upsampling? It moves the jaggies further up the spectrum ie decrease jaggies spacing? Am I on the right track?
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post #20 of 41
2/28/10 at 3:55pm
Quote:
Originally Posted by SP Wild View Post
Fascinating images, Those jaggies look nasty. Do they exist at a 44.1 khz frequency?
They represent frequencies of 44.1 kHz and above.

Quote:
Hence the need to roll-off at 22khz so we do not hear these jaggies?
Only if you can hear out to 44.1kHz.

And you wouldn't need to filter at 22 kHz. The reason for filtering at 22 kHz is when doing the original A/D conversion to avoid aliasing (it's called an anti-aliasing filter as opposed to a reconstruction filter which is applied to the output after D/A conversion).

Some choose to forgo the reconstruction filter altogether seeing as you can't hear out to 44.1 kHz nor would most loudspeakers or headphones be able to reproduce anything that high anyway.

Others argue that the high frequency components can result in intermodulation products that can show up in the audible band.

Quote:
What off upsampling? It moves the jaggies further up the spectrum ie decrease jaggies spacing? Am I on the right track?
Pretty much, yup.

se
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post #21 of 41
3/6/10 at 4:06pm
Quote:
Originally Posted by Koyaan I. Sqatsi View Post
What they fail to mention is that stair-step nature of the waveform represents frequencies at and above the sampling rate, i.e. 44,100 Hz in the case of Compact Disc.
I'm a little confused by this statement. In the figure it looks like the oscillation is being sampled ~22 times in one cycle. Wouldn't that make the approximate cycle of the wave about 2KHz? Also I thought that the Nyquist sampling criterion states that the highest frequency that can be reconstructed from samples is 1/2 of the sampling rate (so just 22,050 Hz for CD's).
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post #22 of 41
3/7/10 at 6:41am
Quote:
Originally Posted by eucariote View Post
I'm a little confused by this statement. In the figure it looks like the oscillation is being sampled ~22 times in one cycle. Wouldn't that make the approximate cycle of the wave about 2KHz? Also I thought that the Nyquist sampling criterion states that the highest frequency that can be reconstructed from samples is 1/2 of the sampling rate (so just 22,050 Hz for CD's).
Those images are for illustration only. If you drew a single cycle of 44.1kHz sampled sine-wave on a computer screen you'd not be able to see the steps.
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post #23 of 41
3/7/10 at 7:54am
It's all in the mastering! Some formats (vinyl, SACD, DVD-A) sound better than the CD because the mastering is different!

If the mastering is exactly the same in the digital formats, there should be no difference. One mastering engineer believes that SACD sounds farther away from the master than CD. I have heard many a CD sound as good, if not better, than analog counterparts. Of course, the mastering was different.
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post #24 of 41
3/7/10 at 8:06am
Quote:
Originally Posted by Hudson View Post
Those images are for illustration only. If you drew a single cycle of 44.1kHz sampled sine-wave on a computer screen you'd not be able to see the steps.
If the sine wave was 22Khz you sure would see the steps, one entire wavelength would be represented by just 2 samples.
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post #25 of 41
3/7/10 at 8:27am
Quote:
Originally Posted by Shark_Jump View Post
If the sine wave was 22Khz you sure would see the steps, one entire wavelength would be represented by just 2 samples.
Whoops, of course yeah. What you see will be relative to the frequency of the wave being sampled too. My bad.
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post #26 of 41
3/7/10 at 11:13am
Quote:
Originally Posted by Shark_Jump View Post
If the sine wave was 22Khz you sure would see the steps, one entire wavelength would be represented by just 2 samples.
Would those two samples per wavelength be enough to perfectly reproduce the 22kHz sine wave since 22kHz is less (just less) than half of the 44.1kHz sampling rate?
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post #27 of 41
3/7/10 at 11:34am
except that apparently all DAC's are not born equal:

Mother of Tone - Conversion Techniques

Upsampling vs. Oversampling for Digital Audio

I wonder what's supposed to clean the noise off a delta/sigma DAC output...the infamous LPF opamps? no wonder high grade opamps pay off then
Quote:
Originally Posted by LFF View Post
One mastering engineer believes that SACD sounds farther away from the master than CD.
it's been thoroughly agreed that SACD sounded better due to superior mastering....listen to DM's Violator, and become a believer.
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post #28 of 41
3/7/10 at 12:35pm
Quote:
Originally Posted by Ham Sandwich View Post
Would those two samples per wavelength be enough to perfectly reproduce the 22kHz sine wave since 22kHz is less (just less) than half of the 44.1kHz sampling rate?
Theoretically yes, assuming you had a perfect reconstruction filter.
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post #29 of 41
3/7/10 at 12:55pm
Quote:
Originally Posted by Hudson View Post
Those images are for illustration only. If you drew a single cycle of 44.1kHz sampled sine-wave on a computer screen you'd not be able to see the steps.
That's because the programs filter the waveform on-screen.

Silk: CuteStudio Ltd. Audio, electronics, graphics and embedded software - products/audio/seedeclip

That program, among many other features can show the real waveform as it really is in the file.

Quote:
"Viewing digital and analog waveforms
Many people do not appreciate that the CD medium is actually quite coarse for music, in terms of sampling rate and the number of levels for quiet signals. The SeeDeClip graphing software can display the signal either as the actual digital signal, sample by sample, or as an analog 'join-the-dots' view. This was mainly added for interest as the actual digital shape is quite revealing."
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post #30 of 41
3/7/10 at 1:23pm
Quote:
Originally Posted by SP Wild View Post
Fascinating images, Those jaggies look nasty. Do they exist at a 44.1 khz frequency? Hence the need to roll-off at 22khz so we do not hear these jaggies? What off upsampling? It moves the jaggies further up the spectrum ie decrease jaggies spacing? Am I on the right track?
That image is misleading. Yes, with digital the sound is not saved as a whole, but as samples. But DACs reconstructs the wave from the samples and the output resembles the analog picture.
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