"MZ" wrote in message
...
But what is it? Do you not agree that if the waveform produced by
amplifier A perfectly matches the waveform produced by amplifier B, there
will be no difference in sound?

Of course. Unfortunately, they don't measure as accurately as you think
they
do.

Yes they do. Today's modern test equipment is extremely precise. Much
more precise than our senses. It can introduce a virtually nonexistent
impedance (thank goodness for op amps) and has an error of measurement far
below what you think it is. The error is usually listed in the manual or
on the back of the machine itself.

No, you still don't get it. You still think, for example, that because we can
detect parts per billion, that scientific measuring devices are more precise
than our tongue and nose. It's not a question of precision, it's a question of
accuracy. Those tools are not measuring the same way we're measuring. It's too
complicated. The wine example was a good one. Even though they can do a
chemical analysis on it, they still can't determine which blend of tastes and
smells will make up a good wine and which will taste best. Sure, they can
detect obvious things like spoilage or the presence of some awful chemical, but
they can't figure out which wine would be preferred in a blind tasting.

Yes they do. Today's modern test equipment is extremely precise. Much
more precise than our senses. It can introduce a virtually nonexistent
impedance (thank goodness for op amps) and has an error of measurement
far
below what you think it is. The error is usually listed in the manual
or
on the back of the machine itself.

No, you still don't get it. You still think, for example, that because we
can
detect parts per billion, that scientific measuring devices are more
precise
than our tongue and nose. It's not a question of precision, it's a
question of
accuracy. Those tools are not measuring the same way we're measuring.
It's too
complicated. The wine example was a good one. Even though they can do a
chemical analysis on it, they still can't determine which blend of tastes
and
smells will make up a good wine and which will taste best. Sure, they can
detect obvious things like spoilage or the presence of some awful
chemical, but
they can't figure out which wine would be preferred in a blind tasting.

But what you're failing to grasp here is that we're not trying to classify
perception in and of itself. This discussion is not addressing which forms
of distortion are less pleasing than others, and what the underlying neural
mechanisms are to explain it. The discussion is much simpler than that - it
is whether or not it can be detected in two independent samples. Or, more
precisely, what is the "just noticable difference"? So, using your wine
example, we're not interested in which wine is more fruity. We're
interested in whether or not you can tell the difference between wine A and
wine B, and how test equipment compares in the ability to detect the
difference. Are you still claiming that we're able to detect differences
(not the quality of the difference, but the difference itself) that test
equipment cannot? If you dropped 10 molecules of something into the glass,
would you be able to detect it with your senses? Would the test equipment?

Again getting back to audition, I think the answer is more clearcut. It's
common knowledge that we can measure sounds with sensitive microphones that
simply aren't loud enough for humans. It's also common knowledge that we
can measure harmonic distortion down to millionths of a percent with test
equipment, but we can't make the distinction with our ears. It's also
common knowledge that you can use an SPL meter to tell the difference
between a sound that's 80.000dB and a sound that's 80.001dB, but the best a
human can do is roughly in the 0.5dB range broadband. It's also well known
that humans have a greater difficulty perceiving a narrowband dip in
frequency response than a narrowband boost in frequency response, whereas
test equipment has no such difficulty. We also know that masking can
prevent things from being heard - test equipment does not experience this
phenomenon.

Not only is there demonstrable evidence pointing to the fact that test
equipment can beat all of our sensory modalities (in terms of detection!),
but it's also common knowledge.

"MZ" wrote in message
...
Are you still claiming that we're able to detect differences
(not the quality of the difference, but the difference itself) that test
equipment cannot? If you dropped 10 molecules of something into the glass,
would you be able to detect it with your senses? Would the test equipment?

OK, well some test equipment can, and some can't. Whether the test equipment
exists today that is good enough to tell what I can tell with my ear is one
question (I don't know whether it exists or not.) Whether that is the test
equipment that is actually used to do a review is another thing. (I'm sure some
reviews have been done with cheaper, less accurate equipment.)

Again getting back to audition, I think the answer is more clearcut. It's
common knowledge that we can measure sounds with sensitive microphones that
simply aren't loud enough for humans.

Right.

It's also common knowledge that we
can measure harmonic distortion down to millionths of a percent with test
equipment, but we can't make the distinction with our ears. It's also
common knowledge that you can use an SPL meter to tell the difference
between a sound that's 80.000dB and a sound that's 80.001dB, but the best a
human can do is roughly in the 0.5dB range broadband.

OK, but again - that is what is *possible* (I'm just taking your word for it.)
I can assure you that that is not the equipment that is being used for most
reviews (or at least has been used in the past.) It's either because such
equipment is just too expensive, or too difficult to use correctly, or maybe
even because the reviewer already believes such precision isn't relevant.

Not only is there demonstrable evidence pointing to the fact that test
equipment can beat all of our sensory modalities (in terms of detection!),
but it's also common knowledge.

But it's not common practice.

OK, well some test equipment can, and some can't. Whether the test
equipment
exists today that is good enough to tell what I can tell with my ear is
one
question (I don't know whether it exists or not.) Whether that is the
test
equipment that is actually used to do a review is another thing. (I'm
sure some
reviews have been done with cheaper, less accurate equipment.)

It depends what you refer to when you say "what I can tell with my ear". If
you're referring to detection of harmonic distortion, detection of noise, or
detection of IMD, then I can tell you with certainty that we've long had the
test equipment to be able to perform such simple measures. In fact, all you
need is a high quality microphone to capture the signal, and the analysis
can be done on any PC (with free software, no less!). But if instead you
mean whether or not we have test equipment to detect the mood of someone's
voice, to detect a voice as someone you know under all conditions (eg. even
when their voice is altered because they have a cold, etc), or to translate
a voice into speech, then no, the human brain is still superior to test
equipment. But again, I'm not talking about determining which sound is
better, more musical, warmer, brighter, smoother, realistic, etc. I'm
simply referring to whether or not one can detect a difference under a
controlled setting.

As for the equipment that's used to bench amps, nothing terribly expensive
or elaborate is required. In recent years, I've used expensive data
acquisition cards to do that sort of thing. I've used simpler USB data
acquisition devices. And, even more recently, I've used a good sound card's
input, a homemade attenuator, and some custom written matlab software to do
it. People who benchtest for a living undoubtedly use more sophistocated
equipment, but it's not necessary IMO. In short, you can get incredibly
precise equipment for extremely low prices. Hell, Arny Krueger benches
soundcards WITH a soundcard, and his tests are among the most comprehensive
available!

When you can hook up test equipment to the human brain then you will have an
instrument that can measure sound the way we perceive it. Test equipment
can't hear-test equipment doesn't have ears. Test equipment can measure and
take the sound waves and turn it into electronic impulses to be read on a
screen and then subjectively analyzed. You will never have a machine that
can tell you what a wine tastes like. Unless you can hook it into a human
brain. My point is that your electronic waveform is not telling the whole
story.

I agree that my tests were not ideal and I did know the amps involved. In
fact, I wanted to like the amp I thought lacked the ability to allow my
human ears hear all there is to hear in the upper octaves of the music I
used for my tests. This guy Clark can claim anything he wants. Is he a
scientist doing controlled experiments. Not likely just some guy trying to
make a name for themselves.

Science is mostly theory. There is not much fact to science. Scientist do
research and complete studies and can come to a reasonable conclusion but
most of what they do is theory and can usually be challenged by another
researcher with their own theories.

Who is to say all humans hear or see the same exact way. We just don't
know. We certainly know that not all human taste food the same because
there are people who have their favorites which may be your most hated
foods.


"jeffc" wrote in message
...

"MZ" wrote in message
...
Are you still claiming that we're able to detect differences
(not the quality of the difference, but the difference itself) that test
equipment cannot? If you dropped 10 molecules of something into the
glass,
would you be able to detect it with your senses? Would the test
equipment?

OK, well some test equipment can, and some can't. Whether the test
equipment
exists today that is good enough to tell what I can tell with my ear is
one
question (I don't know whether it exists or not.) Whether that is the
test
equipment that is actually used to do a review is another thing. (I'm
sure some
reviews have been done with cheaper, less accurate equipment.)

Again getting back to audition, I think the answer is more clearcut.
It's
common knowledge that we can measure sounds with sensitive microphones
that
simply aren't loud enough for humans.

Right.

It's also common knowledge that we
can measure harmonic distortion down to millionths of a percent with test
equipment, but we can't make the distinction with our ears. It's also
common knowledge that you can use an SPL meter to tell the difference
between a sound that's 80.000dB and a sound that's 80.001dB, but the best
a
human can do is roughly in the 0.5dB range broadband.

OK, but again - that is what is *possible* (I'm just taking your word for
it.)
I can assure you that that is not the equipment that is being used for
most
reviews (or at least has been used in the past.) It's either because such
equipment is just too expensive, or too difficult to use correctly, or
maybe
even because the reviewer already believes such precision isn't relevant.

Not only is there demonstrable evidence pointing to the fact that test
equipment can beat all of our sensory modalities (in terms of
detection!),
but it's also common knowledge.

But it's not common practice.

Trader wrote:

When you can hook up test equipment to the human brain then you will have an
instrument that can measure sound the way we perceive it. Test equipment
can't hear-test equipment doesn't have ears.

Test gear cannot duplicate the BAD things involved in human
hearing like predjudice, or lack of high frequency response that
some folks have or DEAFNESS.... ;-)

But test gear for audio is FAR more accurate than a humans
perception... If you can hear the difference it can be measured!!!

But, some folks IMAGINE that they hear differences when no
differences really exist, those of course cannot be measured!!

Not differences in HOW YOU HEAR, but differences in the
sounds you hear....

You will never have a machine that
can tell you what a wine tastes like.

Im not aware of test equipment that measures tastes, and if there
were any, I would not be prepared to compare its accuracy to
that of audio test gear...Which BTW I am very familiar with...

I can measure sound differences that folks CANNOT HEAR
but I have never seen a LEGITIMATE sound difference that
someone can actually hear that I cannot measure,,...

And isnt this getting off the point about amps sounding different?
Those that think they do are either not conducting the tests correctly
OR being influenced by other variables....


Science is mostly theory. There is not much fact to science.

Not in my science textbooks... I have LOTS of facts... Thats the
basis of SCIENCE!!

You must be confused with SCIENCE FICTION!! ha ha



Eddie Runer
installin since 1974
http://www.installer.com/tech/

When you can hook up test equipment to the human brain then you will have
an
instrument that can measure sound the way we perceive it. Test equipment
can't hear-test equipment doesn't have ears. Test equipment can measure
and
take the sound waves and turn it into electronic impulses to be read on a
screen and then subjectively analyzed. You will never have a machine that
can tell you what a wine tastes like. Unless you can hook it into a human
brain. My point is that your electronic waveform is not telling the whole
story.

I understand what your point is. However, it's incorrect. The sound wave
is being captured by the device. It is being transduced from mechanical
energy (that's what a sound wave is) to electrical energy. The output is
then sent on to a machine to be analyzed. Now, I bet you're thinking that
I'm talking about a microphone. But I'm talking about the ear! It behaves
in essentially the same way that a microphone behaves (but, instead of using
Faraday's law, it uses ion channels triggered by movement of hair cells).
So the microphone is using the same exact piece of information to make its
measurement (compression and rarefaction of air molecules). Therefore, it
can't possibly have more information available to it than the microphone.
So, in light of this explanation, how could it not be telling the whole
story?

Science is mostly theory. There is not much fact to science.

Not sure what this means. We derive facts from logic. Science is applied
logic.

Scientist do
research and complete studies and can come to a reasonable conclusion but
most of what they do is theory and can usually be challenged by another
researcher with their own theories.

Right. So I suggest you dig up just one researcher who believes that the
ear works on something other than sound waves - or whatever it is you're
suggesting. Frankly, I don't think you know what it is you're suggesting.


Who is to say all humans hear or see the same exact way. We just don't
know.

Well, if you mean who is to say that all humans have the same abilities,
they don't. This has been examined. There is of course a range of
capabilities, and we know what it is.

We certainly know that not all human taste food the same because
there are people who have their favorites which may be your most hated
foods.

You're getting confused. People do indeed have preferences. They like
different kinds of sounds, different kinds of music. That doesn't mean that
some people have different hearing capabilities because of it. The
information getting TO the brain (that allows you to then make decisions
about what you like and what you don't like) is limited. And I've tried to
explain to you that these limitations, while not identical in everyone, are
in a certain range. And that range is far from the level that exists
between the two amplifiers.

"MZ" wrote in message
...
So the microphone is using the same exact piece of information to make its
measurement (compression and rarefaction of air molecules). Therefore, it
can't possibly have more information available to it than the microphone.
So, in light of this explanation, how could it not be telling the whole
story?

The problem is not the information. The problem is the measurement of the
information. First, you are not strictly correct - the microphone does not
have the same information available to it, because it's not shaped like an
ear. If it were, not all human ears are shaped the same. But that's not
relevant. The real problem is that microphones are not perfect and can't
send a perfect signal to be analyzed. There is always some distortion of
the original signal.

So the microphone is using the same exact piece of information to make its
measurement (compression and rarefaction of air molecules). Therefore, it
can't possibly have more information available to it than the microphone.
So, in light of this explanation, how could it not be telling the whole
story?

The problem is not the information. The problem is the measurement of the
information. First, you are not strictly correct - the microphone does not
have the same information available to it, because it's not shaped like an
ear. If it were, not all human ears are shaped the same. But that's not
relevant.

The pinna introduces distortion, actually. That's the point of it. It
improves high frequency response for sounds coming in front of you (this
is good) but intentionally blocks high frequencies for sounds coming
behind you. As such, it assists the brain with localization.
Importantly, it's also responsible for the brain's ability to estimate
elevation of the source. You'll note that it's not symmetrical from top
to bottom. Early auditory areas deep in the brain spend the bulk of their
resources making these computations (the inferior colliculus perhaps the most
prominent - anyway, not even having reached the cortex yet).

This is an example of the auditory system, like all of the other sensory
systems, intentionally introducing distortion into the signal in order to pull
out attributes of the stimulus that are important for the animal to work. The
visual system is probably even more guilty of employing this strategy. It's a
common trend, all the way from humans to invertebrates.

So yes, it's a GOOD THING that microphones don't use these tricks. We
want accuracy, so ideally it will collect sounds from all directions
equally.

The real problem is that microphones are not perfect and can't
send a perfect signal to be analyzed. There is always some distortion of
the original signal.

But substantially less than the human auditory system introduces.
Microphones tend to have a reasonably flat response from 20 to 20kHz (the
good ones at least). The human auditory system has an awful response,
peaking around 1kHz or less (the dominant part of human speech,
incidentally) and responding poorly above 15kHz and below about 100Hz.
Additionally, microphones have a cleaner transduction mechanism, not
having to rely on a network of bones attached to an asymmetric diaphragm.
Also, the auditory system inherently produces its own distortion known as
otoacoustic emissions which are much more significant than distortion
effects produced by decent microphones. Finally, and most importantly,
the microphone is able to make an electrical measurement that's limited
only by the inductance of the coil (which is why it's able to have such a
great spectral range). The auditory system, however, relies on a network
of neurons that are each tuned to relatively wide band of frequencies to
encode the signal by essentially performing a rough fourier transform of
the signal, and then, before the signal is even transmitted to the brain,
computations are performed to essentially subtract adjacent frequencies
from each other (a form of lateral inhibition - another bit of distortion
added to the system). As a result, the signal being sent to the brain is
a far cry from the signal that reached the ear drum.

In short, microphones do a much better job at capturing the original
signal than does the human auditory system. Not only because it uses more
precise materials and mechanisms, but also because it's designed for
perfect reproduction - the auditory system is not.

jeffc wrote:

The problem is not the information. The problem is the measurement of the
information.

Not rellavent!!

Since I can measure sounds so minute no one can hear them
and since no one has yet proved they can hear things I cant
measure, (many folks IMAGINE they can), then your point
is irrelevent to these arguements...

Eddie Runner
http://www.installer.com/tech/