SACD vs. CD - Unfair competition?

[Feanor]

...Let's look at this from another angle. Let's assume we have two signals which are identical but signal B is delayed by 5 microseconds. I presume this is what we are talking about. Now let's assume these signals are a 1kH sine wave with an amplitude of +/- 1 volt.

...
I think that clearly shows that a 5 microsecond delay is captured quite well with a 20 microsecond sampling interval. As a matter of fact, I think the number of bits representing those analog amplitude values have more of an affect on capturing the delay than the sampling rate does.

Further, using Nyquist's Theorum, the above will hold true for frequencies up to 24 kHz.

Your example proves that 44.1KHz can distinguish two sine waves 5 us apart. But we don't listen to sine waves. Suppose there is a pair of complex wave forms where there are instantaneous spikes 5 us apart?

[WmAx]

Your example proves that 44.1KHz can distinguish two sine waves 5 us apart. But we don't listen to sine waves. Suppose there is a pair of complex wave forms where there are instantaneous spikes 5 us apart?

Spikes? You mean 'impulses'? That's not something you find in music or nature. However, with nearly any natural sound, you can express the signals as a sum of sine waves. This extends to any symmterical waveform(as opposed to assymetrical which is only common in a synthetic environment(usually test signals)): square wave, triangle wave, etc. They are a result of many sine waves.

-Chris

[Feanor]

Spikes? You mean 'impulses'? That's not something you find in music or nature. ...

... if not in music. Isn't true that supersonic events, (at least), cause impulses? These everts aren't all that uncommon, e.g. base ball hit by a bat, crack of a bull wip, gun shots, some explosions. No wonder these things never sound real except heard live!

[WmAx]

... if not in music. Isn't true that supersonic events, (at least), cause impulses? These everts aren't all that uncommon, e.g. base ball hit by a bat, crack of a bull wip, gun shots, some explosions. No wonder these things never sound real except heard live!

The events you describe are composed of primarily symmetrical waveforms. Perhaps not perfect, but I don't know. An impulse is assymetrical. However, this is immaterial. It is possible for some speakers to reproduce assymetrical waveforms with great accuracy.

An assymetrical waveform is one that does not have inversely matching values in it's two 180 degree halves. These can be seperated and looked at as negative and positive sections of the waveform.

Here are two simplified illustrations, represent a waveform with symetry and the same waveform without.

Symmetrical Wave form

+ Pos
.......H..............
.....H...H...........
...H.......H......H.. 0 zero
.............H....H..
................H.....
- Neg


Assymetrical(extreme - for illustration)

+ Pos
......H...............
....H..H.............
..H......HHH....... 0 zero
........................
........................
-Neg

-Chris

[Monstrous Mike]

Your example proves that 44.1KHz can distinguish two sine waves 5 us apart. But we don't listen to sine waves. Suppose there is a pair of complex wave forms where there are instantaneous spikes 5 us apart?

A spike of 5 us would certain be missed by a sampling interval of 20 us. However, that 5 us pulse would have frequency components in the 384 kHz range or greater and thus are not audible and cannot be reproduced by standard amplifiers or speakers. A sampling interval of 20 us represents a sampling rate of 48 kHz. According to Nyquist Theorem, that means it can only capture frequency components of 24 kHz or less. Spikes and other spurious noise over 24 kHz will not be captured.

So a 48 kHz sampling rate can capture frequencies with a period of 20 us or more and can also capture two signals which are offset by 5 us (assuming a large enough bit word length).

You are confusing time shifting with spectral content..