On Wed, 08 Jun 2005 11:31:23 GMT, "Tim Martin"
wrote:


"Stewart Pinkerton" wrote in message
.. .

That's because you are ignoring reality, as in most of your posts. How
else would you produce an analogue of the original sonic event?

I explained that. One can measure the position of a vibrating diaphragm,

Not with real-world equipment. These aren't mind games, we're talking
about reality here. Besides, you'd have the same self-noise problems
with your proposed measurement system, and *really* serious frequency
response issues.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 08 Jun 2005 14:48:33 GMT, "Tim Martin"
wrote:


"Richard Crowley" wrote in message
...

Congratulations, you have re-invented the microphone.

I think by "microphone" people normally mean a transducer that converts
changes in air pressure into electrical signals.

Indeed they do, although some microphones such as ribbons are more
velocity-sensitive.

It's possible to measure movement without that, and in fact there are
commercial devices using optical measurement to measure such movements.

Specify some. I'm well aware of such devices on machine tools, but not
in this application.

Such devices are not generally termed "microphones".

They are, if they are used as sonic transducers. Basically, you have
*no* idea what you're talking about - but that's been obvious for some
time.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Tim Martin wrote:
"Arny Krueger" wrote in message
...

What you don't seem to realize Tim is the fact that all of
the limiations that you've been obsessing over relate to
both analog and digital signals.

That's incorrect: analog signals are continuous.

And you keep making the same fundamental error over and over again,
when you equate continuous with infinite resolution. It just ain't
so, matter how many times you repeat it.

Between any two points in time where the analog signal is
changing, one can find another point in time where the value
of the analog signal differs from its values at either of
the first two points in time.

And what you utterly fail or refuse to realize is that ALL
the values in between those two points in a continuous
representation are ENTIRELY defined by the bandwidth of the
system. If I know the bandwidth, and I know the data on either
side of of your two points, and those two points are separated
by 1/2*bandwidth, then I can exactly predict the value at ANY
arbitrary point in between.

This is not true for digital representations of analog signals.

Once again, other than stating it over and over and over agin, you
have failed completely to deomstrate your assertion.

Of course, there are limits in how accurately one can represent analog
signals, whether the representation is digital or analog.

Yup, and those limits are imposed first by the fact that NO signal
can have infinite resolution to begin with, your irrational yet
exuberant insistance on infinite energy and time not withstanding
at all. Secondly, the limits are imposed by the bandwidth of the
system and its dynamic range.

But the limits
are in communication channels and storage schemes, not in the signals
themselves.

Not if the signals themselves don't exist for infinite time, have
infinite bandwidth and have inifite dynamic range.

No matter how many times you repeat you incorrect assertion that
"digital compresses", no matter how many times you misapply,
deliberately or otherwise, the principles of Fourier decomposition,
no matter how many times you invoke physically unrealizable
conditions or theoretically ridiculous signals, no matter how many
times you attempt to sidestep the issue with irrelevancies in
an attempt to support your assertion, the assertion still remains
incorrect.

Tim Martin wrote:
However, if you think what I said is incorrect, please show it. In the case
of the bird singing in the woods, demonstrate there are two points in
time,where the analog signal in the interval between those two ponts in time
is unchanging.

No one ever said that the signal is unchanging. That's a strawman
that you alone erected.

What one CAN say, most definitely, is that the number of possible paths
the signal CAN take between the two points is limited by the interval
between those two points and the bandwidth of the signal. Make the
bandwidth narrow enough, or make the two points close enough, and the
signal is uniquely constrained. At that point, then, if you "sample"
the signal at those intervals, you can have complete knowledge of the
signal wihout having INFINITE knowledge of the signal.

In other words, once you have sampled the signal at a rate fast
enough as defined by the bandwidth of the signal, smapling any
faster WILL NOT give you ANY more information about that signal.
Any extra data is simply redundant and provides no new information
that we could not have already derived from the data we have.

Your repeated assertion is based on the fallacy that any signal,
such as a bird singing in the woods, has infinite information
content. It does not. Once you finally come to that realization,
then you'll see the nonsense of your assertion. You do not need
infinite data to represent finite information.

Now, go ponder your position in the light that no signal has
infinite information content. If you still hold to your position,
please don't bother us until you are able to support that position
with equal the rigor the likes of Shannon applied to the sampling
theorem.

"Wessel Dirksen" wrote in...
Simpler yet, infinity is even ruled out by the very vehicle of sound
propagation itself which can never be infinite. If anything is acoustic
in nature, it can't be of infinite bandwidth otherwise it would violate
Newton's basic law of conservation of energy. To say that any "sound"
has infinite bandwidth is to say that inertia doesn't exist.

Mr. Martin never directly addressed the question of whether he is
posting his messages from the same universe the rest of us are in.
He may not know what "inertia" is in his Martin Universe. :-) His
responses and questions suggest that he may not operating from
the same frame of reference as the rest of us.

"Wessel Dirksen" wrote in message
oups.com...

Simpler yet, infinity is even ruled out by the very vehicle of sound
propagation itself which can never be infinite. If anything is acoustic
in nature, it can't be of infinite bandwidth otherwise it would violate
Newton's basic law of conservation of energy. To say that any "sound"
has infinite bandwidth is to say that inertia doesn't exist.

Sorry, I don't see why there being no lower limit to time resolution in an
analog signal would violate conservation of energy.

Tim

Tim Martin schreef:
"Stewart Pinkerton" wrote in message
...

That's incorrect: analog signals are continuous. Between any two points
in
time where the analog signal is changing, one can find another point in
time
where the value of the analog signal differs from its values at either of
the first two points in time.

Clearly, you have absolutely *no* understanding of the real physical
world. Go learn about uncertainty, before you spout such nonsense
here.

As usual, instead of commenting on the point made, you put up a smokescreen.

However, if you think what I said is incorrect, please show it. In the case
of the bird singing in the woods, demonstrate there are two points in
time,where the analog signal in the interval between those two ponts in time
is unchanging.

Tim

Tim,

I added this above but I'll repeat it because it may make this clear;
aside from Nyquist, bits etc which I don't understand much of either.

Any sound must be produced mechanically because something must push
molecules into movement. Anything with mass cannot accellerate
infinitely fast. You must know this; "objects at rest tend to stay at
rest . . ." So it is impossible to have an infinite bandwidth soundwave
purely because it could never be produced mechanically. A birds cloaca,
or whatever it uses, has a HF limit where you can't accelerate its mass
fast enough back and forth and thus the HF response has a very definite
limit. On top of that, even the mass of molecules moving back and forth
in a sound wave are limited in the same way.

wrote in message
oups.com...

What one CAN say, most definitely, is that the number of possible paths
the signal CAN take between the two points is limited by the interval
between those two points and the bandwidth of the signal. Make the
bandwidth narrow enough, or make the two points close enough, and the
signal is uniquely constrained. At that point, then, if you "sample"
the signal at those intervals, you can have complete knowledge of the
signal wihout having INFINITE knowledge of the signal.

Great, a comment with some substance.

OK, let's suppose our signal is a 1kHz sine wave, followed by a period of
silence, followed by a 1kHz sine wave. The amplitude of the sine wave is
the minimum that can be represented in our digital scheme. And let's
suppose our sampling rate is 50000 times a second .... that is, one sample
every 20 microseconds..

Now, I think that an analog signal with a silence of 200 microseconds will
result in the same digital representation as an analog signal with a silence
of 201 microseconds.

Do you agree or not?

Tim

Tim Martin wrote:
wrote in message
oups.com...

What one CAN say, most definitely, is that the number of possible paths
the signal CAN take between the two points is limited by the interval
between those two points and the bandwidth of the signal. Make the
bandwidth narrow enough, or make the two points close enough, and the
signal is uniquely constrained. At that point, then, if you "sample"
the signal at those intervals, you can have complete knowledge of the
signal wihout having INFINITE knowledge of the signal.

Great, a comment with some substance.

OK, let's suppose our signal is a 1kHz sine wave, followed by a period of
silence, followed by a 1kHz sine wave. The amplitude of the sine wave is
the minimum that can be represented in our digital scheme. And let's
suppose our sampling rate is 50000 times a second .... that is, one sample
every 20 microseconds..

Now, I think that an analog signal with a silence of 200 microseconds will
result in the same digital representation as an analog signal with a silence
of 201 microseconds.

Wrong, because the signal you describe CANNOT be represented in a
system with finite bandwidth, a fundamental principle you abjectly
refuse to grasp. More importantly, you've described a signal that
you cannot even create in the real universe.

Only unless you are willing to say that you have a signal produced
in a "system" whose bandwidth is such (and such infinity), that
signal cannot exist in ANY representation, continuous, discrete or
otherwise.

As soon as you come to the realization that the bandwidth MUST be
limited in any realistic signal, you can then have a perfect
discrete sampled representation of that signal.

Your continued unsupportable protests to the contrary, e.g., what
you think, is irrelevant.

"Tim Martin" wrote in message
...

"Wessel Dirksen" wrote in message

oups.com...

Simpler yet, infinity is even ruled out by the very
vehicle of sound
propagation itself which can never be infinite. If
anything is acoustic
in nature, it can't be of infinite bandwidth otherwise
it would violate
Newton's basic law of conservation of energy. To say
that any "sound"
has infinite bandwidth is to say that inertia doesn't
exist.

Sorry, I don't see why there being no lower limit to time
resolution in an
analog signal would violate conservation of energy.

A lower limit to time resolution is a consequence of the
signal having finite duration. If the signal went on
indefinitely it would have no lower limit.

If the signal went on indefinitely and had finite energy in
all or most finite time segments, then the total signal
would have infinite amounts energy.

Now if the presence of infinite amounts of energy doesn't in
some sense violate the law of conservation of energy... ;-)

"Arny Krueger" wrote in message
...
If the signal went on indefinitely and had finite energy in
all or most finite time segments, then the total signal
would have infinite amounts energy.

Now if the presence of infinite amounts of energy doesn't in
some sense violate the law of conservation of energy... ;-)

Of course the duration cannot be infinite, ie. longer than the universe
existence.

MrT.

On Thu, 09 Jun 2005 11:35:28 GMT, "Tim Martin"
wrote:


"Wessel Dirksen" wrote in message
roups.com...

Simpler yet, infinity is even ruled out by the very vehicle of sound
propagation itself which can never be infinite. If anything is acoustic
in nature, it can't be of infinite bandwidth otherwise it would violate
Newton's basic law of conservation of energy. To say that any "sound"
has infinite bandwidth is to say that inertia doesn't exist.

Sorry, I don't see why there being no lower limit to time resolution in an
analog signal would violate conservation of energy.

That's because you don't understand the subject. No lower limit to
time resolution = infinite bandwidth = infinite energy.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

wrote in message
oups.com...

Wrong, because the signal you describe CANNOT be represented in a
system with finite bandwidth, a fundamental principle you abjectly
refuse to grasp. More importantly, you've described a signal that
you cannot even create in the real universe.

So, you're saying I cannot create a signal comprising a 1kHz sine wave with
small amplitude, followed by a period of silence, followed by a 1kHz sine
wave with small amplitude.

Tim

Tim Martin wrote:
wrote in message
oups.com...

Wrong, because the signal you describe CANNOT be represented in a
system with finite bandwidth, a fundamental principle you abjectly
refuse to grasp. More importantly, you've described a signal that
you cannot even create in the real universe.

So, you're saying I cannot create a signal comprising a 1kHz sine wave with
small amplitude, followed by a period of silence, followed by a 1kHz sine
wave with small amplitude.

No, you're saying that you can.

So, prove us wrong. Produce for us this signal EXACTLY as you have
described it (ignoring the fact, for the moment, that your description
of such signal is QUITE inexact) through any means at your disposal.
By signal, I don't mean an equation (continuous or otherwise), or
a drawing on a piece of paper or any such dodge. I mean a signal.
It can be acoustical, electrical, mechanical, what have you.

By the way, as you HAVE provided a woefully incomplete description,
how about we better define the signal? How long is the 1 kHz
signal? Exactly when does it end? How long is the silence? Exactly
when does it end? How silent is silent? How long is the second period
of the 1 kHz since wave? How small is its amplitude?

Fine, you say it can, so produce it.

Let us know.

On Thu, 09 Jun 2005 16:08:47 GMT, "Tim Martin"
wrote:


wrote in message
roups.com...

Wrong, because the signal you describe CANNOT be represented in a
system with finite bandwidth, a fundamental principle you abjectly
refuse to grasp. More importantly, you've described a signal that
you cannot even create in the real universe.

So, you're saying I cannot create a signal comprising a 1kHz sine wave with
small amplitude, followed by a period of silence, followed by a 1kHz sine
wave with small amplitude.

If you allow the sine wave a finite period of attack and decay, and
the 'silence' to have a noise floor, then of course you can.
Otherwise, no one can.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Thu, 09 Jun 2005 11:48:47 GMT, "Tim Martin"
wrote:


OK, let's suppose our signal is a 1kHz sine wave, followed by a period of
silence, followed by a 1kHz sine wave. The amplitude of the sine wave is
the minimum that can be represented in our digital scheme. And let's
suppose our sampling rate is 50000 times a second .... that is, one sample
every 20 microseconds..

Now, I think that an analog signal with a silence of 200 microseconds will
result in the same digital representation as an analog signal with a silence
of 201 microseconds.

Do you agree or not?

No. You're describing an analogue waveform ending towards infinite
bandwidth. It can't exist in analogue or digital represention

(If it COULD, you'd be thanking the digital system for ironing out
such glitches, not complaining about low resolution :-)

On Thu, 09 Jun 2005 16:08:47 GMT, "Tim Martin"
wrote:

So, you're saying I cannot create a signal comprising a 1kHz sine wave with
small amplitude, followed by a period of silence, followed by a 1kHz sine
wave with small amplitude.

Not if you want that period of silence to be as short as we've been
discussing. No you can't. You can describe it as a theoretical
possibility. But, lacking resources tending to the infinite, you
can't create it.

"calmar" wrote in message
...
Hi,

I'm wondering, how a good computer with a good graphic card + good
speakers can compare to a good HiFi System?

Since good soundcards can be quite expensive, and that only for the
card
itself, I would suspect, that that good computer/soundcard and good
speaker combo can be as good as a good HiFi System?

So I really don't know much about these things.


Thanks for any hints.

calmar

For a long time now I have plugged my various PC sound card outputs
(line level, not speaker output) into the AUX input of "surplus"
stereo receivers (1970's to 80's vintage, around 15 to 25 wpc) and
used whatever "spare" stereo speakers that were around at the time.
The results have been generally good for CD's played on the PC. But
all this stuff is in in the office so I can't do an A-B comparison
with my main system.
Anyway, try it. What can you lose?
Cheers,
Roger