In article ,
All Ears wrote:
Beyond that, I am not saying that the result is "bad and
unnatural," That's a judgement I will not make because it is a
preferential thing.

I am refuting your claim that such an amplifier could ever
possibly measure even remotely the same. My argument is not
whether the result saound good or bad, that's your decision to
make. My argument is to directly challenge your claim that this
amplifier could measure like any other IN SITU: they can't, it's
as simple as that.

Thus, your premise, or your question, as the case may be, "how
can two amplifier that have similar specs sound so different" is
is meaningless in the face of the fact that two such amps SIMPLY
CAN'T HAVE SIMILAR SPECS.

Do you understand the point?

Yes I think we agree about this point,

It is clear to me we do not, because I feel you are still
laboring under a set of fundamental misunderstandings qbout how
things work.

but I am still wondering how an OTL
can obtain such a good tonal balance and speaker control with such a high
output impedance,

I did NOT say "good" or "bad." I said, in direct refutation of
your point, that they cannot measure the same. Thus your premise
that "they measure the same but sound different" is entirely
refuted on its face.

I am even using 4 ohm speakers, which presents no problem
at all.

BY this statement alone, it is clear to me you do not understand
the technical imlications of the issue of OTL output impedance,
because it is more significant with 4 ohm speaker than with 8
ohm speakers.

I would guess that you have listend to a few OTLs yourself, and
could have had the same thoughts.

Why would you assume so?

Actually, the speakers I use are all designed by tube lovers,

A comment on this: there are really VERY few really competent
speaker designers. Just being a lover of tubes does not qualify
one to design speakers for them.

Sir, I believe yo do NOT understand the difference between the
terms "current source" and "voltage source" and, further, you
have a misunderstanding of the operation of loudspeakers, as I
pointed out and hopefully set you on a more correct path in a
different post.

These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source applies
very well.

No, it os no ABUNDANTLY clear that your do not understand the
meaning of the term "current source" or "voltage source." It has
NOTHING to do with what you are desribing, which, by the way,
you are not describing correctly anyway.

The DEFINITION of a current source is very simple: a current
source is one whose effective Thevenin source impedance is
substantially larger than the load impedance. A voltage source
os one whose effective Thevenin source impedance is
substantially smaller than the load impedance. Period. All the
other hooey and hoopla and handwaving is nonsense.

And the result is real simple: driving a frequency dependent
load impedance from a current source will ALWAYS result in the
imposition of frequency response variations on the output of
that source and thus on the system as a whole in a way that is a
function of the load impedance.

Period. This is not some narrow-minded high-end agenda-driven
pseudo-definition, this is a precise technical description of
the physical behavior of the system.

It should be possible to find a few serious manufactures in the industry,
anyway, a standard would give a goal to persue for the serious ones. It
could be implemented like the ISO or similar standard.

You missed the point, the standard ALREADY exist: it is the
high-end audio industry that is most guilty of egregious
violations of these standards. The high-end industry seems also
to be the least technically competent to follow such standards.

There are almost no specifications available for the OTL's, since they
would
not give an objective idea of the end result.

Oh, precisely the opposite, a complete set of performance data
would give a VERY GOOD iobjective dea of the end result. The
manufacturer might not like the picture painted, but it would be
pretty precise.

I haven't really seen anybody disliking the sound of the few serious OTSs on
the market, but you may be an exception

Excuse me, sir, that is NOT what I said, and that is NOT the
questyion you posed. You stated:

"There are almost no specifications available for the OTL's,
since they would not give an objective idea of the end
result."

And my refutation is that such specification, properly done,
would precisely lead to and exact idea of their objective
performance. You may like listening to the result. You may not.

But when, sir did I say, at ANY point, whether I did or did not
LIKE the result? (Hint: I never did and I object to you claiming
otherwise.)

Absolutely nonsence,

Hardly, if you read your statement.

But your failed to answer the question:

Even if I close my eyes, the OTLs sound great

You failed to answer the question yet again. Methinks you cannot
answer the question.

Why is eliminatiung the direct knowledge of what equipment
is playing a hinderance to relaxation?

Please answer that question, as it is at the very root of your
complaints about DB testing.
As a music lover, I am merely reporting observations, not writing sceintific
reports. I can only encurage people to use their own ears, and judge for
themselves.

But, if you KNOW the brand, if you KNOW what wires and what
amplifiers, guess what YOU AREN'T JUST USING YOUR EARS!

You are contradicting yourself: you say for people to trust
their ears and then you tell them not to.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

In article ,
All Ears wrote:
Ohm's Law certainly does apply. I suggest that you read up on it.

The actual force, that the motor of the driver produces, depends on the
current induced into the coil, right? Does normal speakers have a totally
flat impedance curve? Assuming that the voltage is kept constant, and the
inpedance changes, will this not give an unlinear current, which results
in
amplitude variations over the band? (Rehercing Ohms law

First, what you desribed is NOT Ohm's law.

I replaced resistance with inductance, but the end result will be almost the
same.

In your case, yes, the end result will be the same: the wrong
answer.

Second your analysis falls WOEFULLY short of anything even
barely adequate to describe how speakers work.

Compromises are made to correct for this issue, but they are compromises.

And they are clearly leading you down the wrong path.

You analysis, for example, predicts that under a constant
current, the speaker MUST, below resonance, have a response
which is independent of frequency, i.e., the speaker does not
roll off. Since it does, your analysis in that region is
incorrect.

Of course it rolls off at some point, I used a simplified model.

But your simplified model predicts that it should NOT roll off,
therefore YOUR MODEL AND ANY CONCLUSIONS DRAWN THEREFROM ARE
WRONG.

Don't yet get this simple yet powerful concept?

Secondly, your analysis predicts that even considering the naive
and simple model of current only, the efficiency at resonance
MUST go down, since the impedance rises at resonance, yet it can
be trivially arranged by non-electrical means that even as the
current goes down, the efficiency and the output of the driver
go UP.

To my knowledge, a typical ported speaker goes down in impedance around the
port resonance point, and raises in impedance around the cross over points.
Guess it is a typing error from your side, since the rest of the statement
seems correct.

Sir, again, with all due respect, you really have absolutely NO
idea what you are talking about. I do not mean this as an
insult, and I do not say it lightly, but in all ernest
honestyand with no malice intended. Your really do not
understand in the most fundamental way how loudspeakers operate.
Your notion of the relation of current and acceleration and such
in loudspeakers is so fundamentally flawed that is is leading
you down a path from which you will be unable to make any sound
predictions of the way a speaker operates.

Basically, your basic premise is completely flwed because it
simply ignores the fact that speakers are mechncially resonant
devices, that the simple static model you are relying on fails
immediately once you get out of the region of DC exitation
(which, if you sit down and think it through, is the hidden
assumption in your premise).

Be that as it may, speakers which have flat impedance curve get
there by having complex conjugate circuits tto concel the
impedance variations in the drivers. That means that while they
may have a constant current vs frequency profile AS A SYSTEM,
the drivers themselves do not: they STILL have a current that is
frequency dependent on their individual impedance vs frequency
properties. I would suggest that you get your head out of the
"Ohm's Law" hole and start studying Thevenin, Kirchoff and, once
that's under your belt, start studying Thiele and Small.

Variations of transmission line speakers, can obtain a quit flat impedance
curve, with out complex circuits.

Sorry, my friend, but you arte completely wrong here, I don't
know where you got this notion about the behavior of
transmission lines, but it is simply incorrect in the most
fundamental of ways.

It will be very hard to continue a productive conversation
from this point forward if you insist on holding fast to your
understandings of how loudspeakers work. Rather than continue
and have you lead yourself into some very embarrasing dead ends,
I'd rather one of us simply withdraw.

I have to say that this is a clear case where 22 years in a
hi-fi store did not make you an expert on loudspeakers (assuming
I have my attributions correct, I apologize if I have confused
you with someone else), indeed, I am sorry to say and again,
with no intent to insult, you are simply repeating some
ill-founded myths at best.

How speakers REALLY work is a deeply fascinating topic, one
which your are SO far from viewing with your current position. I
only hope that at some point you can abandon some of your
ill-founded and technically incorrect views and start to
appreciate how things actually work. It's really quite neat when
the understanding REALLY clicks.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

On 28 Jul 2003 19:17:34 GMT, "All Ears" wrote:

Yes I think we agree about this point, but I am still wondering how an OTL
can obtain such a good tonal balance and speaker control with such a high
output impedance,

It cannot and does not (with a nominally flat speaker), you just
*like* that particular combination of amp and speaker.

I am even using 4 ohm speakers, which presents no problem
at all. I would guess that you have listend to a few OTLs yourself, and
could have had the same thoughts.

Quite so. What you are hearing *may* be a serendipitous combination of
a fundamentally inferior amp design and a normally non-flat speaker,
but it's much more likely that you just *like* that sound.

I'll get some solid state current amplifiers next week, this will be
interesting......

Sir, I believe yo do NOT understand the difference between the
terms "current source" and "voltage source" and, further, you
have a misunderstanding of the operation of loudspeakers, as I
pointed out and hopefully set you on a more correct path in a
different post.

These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source applies
very well.

No, it doesn't, in fact you are (badly) describing an overall feedback
system which is trying to do an even better job of producing a
constant voltage source. It's not a new technique. Please avoid
getting into excessively deep technical water.

There are almost no specifications available for the OTL's, since they would
not give an objective idea of the end result.

Oh, precisely the opposite, a complete set of performance data
would give a VERY GOOD iobjective dea of the end result. The
manufacturer might not like the picture painted, but it would be
pretty precise.

I haven't really seen anybody disliking the sound of the few serious OTSs on
the market, but you may be an exception

Count me in also. BTW, an OTL amp is *not* a 'serious' design......

And why is simply eliminating the direct knowledge of what
equipment is playing a hindernace to relaxation? If you HAVE to
know that you are listening to your OTL amplifier in order to
relax, guess, what: YOUR ENJOYMENT ISN'T ABOUT SOUND, IT'S ABOUT
BRAND NAMES!

Absolutely nonsence,

Hardly, if you read your statement.

But your failed to answer the question:

Even if I close my eyes, the OTLs sound great

No one is arguing with your personal preference, but that's not the
point at issue here, and you know it.

But the issue comes when someone makes the claim, "it makes a
difference in the SOUND." You just admitted that a tweak may
work on imagination only, so you just stated that, in such a
case IT ISN'T ABOUT THE SOUND.

As a music lover, I am merely reporting observations, not writing sceintific
reports. I can only encurage people to use their own ears, and judge for
themselves.

So why are you so reluctant to use *only* your ears, without
*knowledge* of which amp is playing?

--

Stewart Pinkerton | Music is Art - Audio is Engineering

On 28 Jul 2003 19:17:34 GMT, "All Ears" wrote:
These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source applies
very well.

One more point, Mr. "Ears," I fear also that your description
above demonstrates a seriously flawed misunderstanding of the
very behavior of feedback. Not, these amplifiers DO NOT "monitor
the impedance at the speakers terminals," and they most
certainly DO NOT "adjust the feedback loop accordingly," and,
further, the term "current source" most certainly DOES NOT apply
as a result. A "current source" DOES NOT MEAN the same thing as
"a source of current," as the correct definition has been given
elsewhere.

Frankly, feedback operation, as it applies to audio amplifiers,
is MUCH simpler and, indeed, much more powerful than your
description implies. And, it should be noted, feedback is one of
the most poorly understood concepts by the high-end community
almost as an intrinsic property of the industry. More out-and-
out hooey and bunkum has been promulgated about feedback by
high-end manufacturers, magazine writers and other
self-appointed but clueless experts than almost any other topic.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

"Norman Schwartz" wrote in message
. net
"Richard D Pierce" wrote:

Face it, the high-end audio industry is DECADES behind behind
the state of the art in many areas, and this is just one
example. I'm not going to give a tutorial on the current range
of available measurements

Measurements haven't led to the construction of great sounding concert
halls, pianos or violins and it appears useful to refer to that which
was done CENTURIES ago.

I'm not really conversant with where the art of making musical instruments
is going, but there's no doubt that modern acoustical architecture, which
does have its triumphs, is heavily based on physical parameters and
measurements.

I don't think that anybody would argue that great concert halls must be
designed based on a detailed understanding of physical parameters and
measurements. However, many modern architects have found that understanding
physical parameters and measurements is of great benefit.

Traditional approaches to building concert halls definitely worked. However,
the rate of developing the necessary largely intuitive understandings was
slow involving centuries, and by the end of the 19th century only a few
working configurations were available. One benefit of modern approaches is
greater flexibility in the general configuration of performance rooms that
can be designed so they sound good.

S888Wheel wrote:
measureable differences that cannot be differentiated by expert
listeners.

Again that is not what he was saying.

Mr. Wheel, do me and yourself a real big favor., You have made
claims about what I said and what I meant and, pretty much, you
got them ALL wrong. Please do NOT pretend that your
interpretation of what I said is the same as what I said, you're
demonstrably bad at it.

Dick was *not* saying that *all*
measureable differences are hard to detect.

There were a lot of things he didn't say.

For example, most of your minsinterpretations of what I said
are, you are quite correct, not things that I said.

I don't think you got the point of
what he did say.

Mr. Wheel, you are about as far from the point as anyone can be.

He was attacking the "claims" of the "experts" based on a
false premise that these "experts" claim to hear differences between amps of
different models but "claim" to not hear differences of different units of the
same model even though they measure differently. I simply pointed out that the
group of listeners he was trying to discredit did not always follow
the premise
he laid down for his argument. He was building his attack on a manufactured
stereotype. It seems you didn't get that.

Mr. WHeel, I would thank you not to build yet another of your
ridiculuous strawmen as you did above. Take from the horse's
mouth, sir, the above is your preposterous, agenda laden total
misinterpretation of my words, and I would thank you to
apologize for your arraogance in attempting to pass them off as
mine.

My point was VERY simple: In ALL cases where differences were
heard, LARGE and CONSISTent differences in measurements are to
be had.

An ALL cases where NO differences where heard, there were STILL
measurable differences.

This was to specifically refute the claim that where differences
where heard, none were measured.

Gentle readers, Mr. Wheel's completely bogus "interpretation"
not withstand, the principle is simple, there are NO cases in my
exyensive experience where a confirmed audible difference was
NOT accompanied by consistant measurement differences.

Mr. Wheel, please to not attempt to "quote" or "interpret" me in
the future, you've demonstrated that you are terrible at it.

Thank you.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

In article XBUUa.141519$GL4.36697@rwcrnsc53,
Wylie Williams wrote:
I keep seeing the following quote:

Further, I can find two samples of the same model and easily
find measurable differences between them, yet "expert" listeners
will claim they sound identical.

I don't know what differences are being referred to. There are all sorts of
possible differences, like small but measurable variations in color, weight,
etc., that I think almost everyone would agree are irrelevant to hearing.
Could it be that some of the other small differences that are being measured
are irrelevant to hearing as well?

What IS it with you people? The principle, despite Mr Wheels
completely boluxed minsinterprations, is simple:

When audible differences are, in fact, shown to exist where
these differences are consistently detectable based on sound
alone, they are ALWAYS accompanied by non-subtle and
consistent differences in measurement of their electrical or
acoustical properties.

This is specifically to refute the common and, frankly,
uninformed myth that there are audible differences while there
are no measurable differences. If you want to add your
ansurdities of color and the likem, that's YOUR choice, and you
have done nothing but confuse the issue.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

In article ,
All Ears wrote:
"Stewart Pinkerton" wrote in message
...
On 27 Jul 2003 17:39:35 GMT, "All Ears" wrote:

"Stewart Pinkerton" wrote in message
...

Speakers are designed to respond
linearly to a constant voltage input, and most modern speakers assume
drive by a constant voltage source, i.e. an amp with very low output
impedance and high reserves of current. This is a fair description of
a good SS amp, but not at all of a tubed OTL amp, which can have
several *ohms* output impedance.

So Ohms law does not apply to speakers, interesting....

Ohm's Law certainly does apply. I suggest that you read up on it.

The actual force, that the motor of the driver produces, depends on the
current induced into the coil, right?

So what? how is that relevant? How does the acoustical output of
the speaker depend upon the applied fource? Unfortunately, your
model will utterly fail at this point to make even a remotely
applicable prediction, because there is a LOT missing from your
"model."

Does normal speakers have a totally
flat impedance curve? Assuming that the voltage is kept constant, and the
inpedance changes, will this not give an unlinear current, which results in
amplitude variations over the band? (Rehercing Ohms law

No, it will give and ENITRELY linear relationship between
current can voltage, since Ohms law:

E = I R

is an entirely linear equation in that a) it is continuous abd
b) it is a first-order expression.

YOu assume there is some maghic connection between current,
force and the response of the speaker. Well, there IS a
relationship, and it IS linear, but it is NOT magic and it is
NOT the relatioship you seem to think it is.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

Dick said


Mr. Wheel, do me and yourself a real big favor., You have made
claims about what I said and what I meant and, pretty much, you
got them ALL wrong. Please do NOT pretend that your
interpretation of what I said is the same as what I said, you're
demonstrably bad at it.

If you didn't mean what you said then say it better next time. You said that
"expert' listeners *will* claim they hear no differences between amps of the
same model that measure differently. Either you can back this claim with some
evidence or you are just stereotyping "expert" listeners.

Dick said


For example, most of your minsinterpretations of what I said
are, you are quite correct, not things that I said.


Cite an example of an actual *misrepresentation* of what you said.

Dick said


Mr. Wheel, you are about as far from the point as anyone can be.


Prove it. Prove that my claim regarding your post inwhich you said..."Further,
I can find two samples of the same model and easily
find measurable differences between them, yet "expert" listeners
will claim they sound identical. What does THAT do to your
"theory?" is as far from the point as anyone can be. If you remember, all I
said about this was that not all "expert" listeners have made this claim. You
were, as I said before, building an argument on a false premise. that's it!
That's all I was saying! Now either prove that you prediction that "expert"
listeners *will* claim said amplifiers sound the same or deal with the fact
that you were caught building an argument on a false premise. It's that simple.

I said


He was attacking the "claims" of the "experts" based on a
false premise that these "experts" claim to hear differences between amps
of
different models but "claim" to not hear differences of different units of
the
same model even though they measure differently. I simply pointed out that
the
group of listeners he was trying to discredit did not always follow
the premise
he laid down for his argument. He was building his attack on a
manufactured
stereotype. It seems you didn't get that.


Dick said

Mr. WHeel, I would thank you not to build yet another of your
ridiculuous strawmen as you did above.

Take from the horse's
mouth, sir, the above is your preposterous, agenda laden total
misinterpretation of my words,

Ridiculous. I should take your word for it that my comments were agenda laden?
Implied mind reading noted. Tell me, how many fingers am I holding up?

Dick said

and I would thank you to
apologize for your arraogance in attempting to pass them off as
mine.

Dick, it is laughable that you would find me arrogant. It is ironic that you
would build a straw man argument to argue that mine was a straw man argument. I
did not misrepresent your words. for the most part I have been quoting them.
You don't like my interpretation of your words? fine. work on saying what you
mean next time. You said...Further, I can find two samples of the same model
and easily
find measurable differences between them, yet "expert" listeners
will claim they sound identical. What does THAT do to your
"theory?" I pointed out that in real life this doesn't always happen. Your
"prediction" of what "expert" listeners *will* do is in direct conflict with
what some of them *have done.* Get it?

Dick said


My point was VERY simple: In ALL cases where differences were
heard, LARGE and CONSISTent differences in measurements are to
be had.

An ALL cases where NO differences where heard, there were STILL
measurable differences.



This was to specifically refute the claim that where differences
where heard, none were measured.


Fine then say this nxt time insted of Further, I can find two samples of the
same model and easily
find measurable differences between them, yet "expert" listeners
will claim they sound identical. What does THAT do to your
"theory?" Which is different and looks quite antagonistic to me toward "expert"
listeners.

Dick said


Gentle readers, Mr. Wheel's completely bogus "interpretation"
not withstand, the principle is simple, there are NO cases in my
exyensive experience where a confirmed audible difference was
NOT accompanied by consistant measurement differences.

Which has nothing to do with my original comment.

Dick said


Mr. Wheel, please to not attempt to "quote" or "interpret" me in
the future, you've demonstrated that you are terrible at it.

I will do what I damn well please so long as the moderators have no problems
with it.

I said


No. His claim was not explicitly qualified nor do I see any implied
qualifications. He was building an argument on a flawed premise. He was
painting a large group of diverse listeners with a stereotype to ridicule
them.

Dick said


Mr. Wheel, this preposterous misinterpretation borders on out
and out dishonesty if you ask me.


I didn't ask you. It is an honest opinion whether you like it or not.

Dick said


My claim is very simple: there have been specific examples where
people making the claim of being expert listeners have presented
me with two pieces of equipment that sounded different, and they
claim that no measurable differences exist: I have quickly and

easily found large measurable differences. They have alson
presented me with equipment that they claim sounded identical,
and I have also found measurable differences, though not as
large.

That is fine but what you actually said was quite different.

Dick said


The rest of your sorry monologue is simply more agenda-laden
nonsense that has nothing to do with what I said.

Bull****. This is what you said..."Further, I can find two samples of the same
model and easily
find measurable differences between them, yet "expert" listeners
will claim they sound identical. What does THAT do to your
"theory?"" I stand by my comments regarding this ridiculous claim.

Dick said

Mr. Wheel, Dick said one thing, Your paraphrasing of what Dick
said is something else entirely. I should know. I am Dick.

Please do NOT use YOUR paraphrasing of what I have said as a
substitute for what I actually said. You have demonstrated in
this thread you are not very good at it.

Thank you.

--
| Dick Pierce |
| Professional Audio Development |

What are you talking about?

"Richard D Pierce" wrote in message
...
On 28 Jul 2003 19:17:34 GMT, "All Ears" wrote:
These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source
applies
very well.

One more point, Mr. "Ears," I fear also that your description
above demonstrates a seriously flawed misunderstanding of the
very behavior of feedback. Not, these amplifiers DO NOT "monitor
the impedance at the speakers terminals," and they most
certainly DO NOT "adjust the feedback loop accordingly," and,
further, the term "current source" most certainly DOES NOT apply
as a result. A "current source" DOES NOT MEAN the same thing as
"a source of current," as the correct definition has been given
elsewhere.

Frankly, feedback operation, as it applies to audio amplifiers,
is MUCH simpler and, indeed, much more powerful than your
description implies. And, it should be noted, feedback is one of
the most poorly understood concepts by the high-end community
almost as an intrinsic property of the industry. More out-and-
out hooey and bunkum has been promulgated about feedback by
high-end manufacturers, magazine writers and other
self-appointed but clueless experts than almost any other topic.

The SS amplifiers I am talking about are equipped with the Anagram Power
Loop module, and does exactely what I described.....


--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

"Richard D Pierce" wrote in message
...
In article ,
All Ears wrote:
And this may well not be the only difference: such an output
impedance is MORE than enough to substantially reduce the
damping of the entire amplifier/speaker system, possibly
DOUBLING its Qt at resonance, which could intriduce ANOTHER 3 dB
of frequency respose error all by itself. You have a system
which has frequency response differences approaching +-4 dB
compared to a driving it with a solid state or even transroemr
coupled tube a,mplifier with appropriate feedback.

With this information in hand, that the OTL amplifier introduces
frequency response variations ranging over +-4 dB compared to a
sommon solid state amplifier, how can you say they meaure the
same? They clearly cannot and DO not.

I do not disagree with what you are saying, but if this was the real
audible
truth, these amplifiers should sound really bad and unnatural, the point
is,
they are not, even compared to very good solid state amplifiers. As I
said,
acoustic instruments (also bass) and voices are the most realistic
reproduced I have heard so far!

"Truth" is what you believe, and may be at odds with the facts.

Beyond that, I am not saying that the result is "bad and
unnatural," That's a judgement I will not make because it is a
preferential thing.

I am refuting your claim that such an amplifier could ever
possibly measure even remotely the same. My argument is not
whether the result saound good or bad, that's your decision to
make. My argument is to directly challenge your claim that this
amplifier could measure like any other IN SITU: they can't, it's
as simple as that.

I never claimed that an OTL could measure the same as an SS amp, it is your
assumption. What I am saying is that these OTLs performs remarkable well
despite of their specifications. By well I mean that they sound very natural
to my ears, and that they reproduce voices and instruments as I would expect
them to sound.


Thus, your premise, or your question, as the case may be, "how
can two amplifier that have similar specs sound so different" is
is meaningless in the face of the fact that two such amps SIMPLY
CAN'T HAVE SIMILAR SPECS.

Do you understand the point?

I do, and answered already.


Actually, the speakers I use are all designed by tube lovers,
furthermore,
the only speaker design that will act in a close to linear way to a
voltage
source, are one way speakers or headphones. All the rest are compromises.
A
speaker reacts in a quite linear way to the current you put into it, not
the
voltage. There are ways of compensating, I know, but again, it is a
compromise.

I'll get some solid state current amplifiers next week, this will be
interesting......

Sir, I believe yo do NOT understand the difference between the
terms "current source" and "voltage source" and, further, you
have a misunderstanding of the operation of loudspeakers, as I
pointed out and hopefully set you on a more correct path in a
different post.

There are such standards, though there is not an all-
encompassing standard for the entire chain (the AES has 40 some
standards, the ISO has the entire realm of 60268, for example),
but, to be frank with you, THE most egregious violators of these
standard is, in fact, the high-end audion industry, ESPECIALLY
when it comes to realistic comparable performance
specifications.

It would be an interesting goal to persue, to get one useful standard for
the entire chain.

But, with the appalling lack of technical expertise in the
high-end industry, they are the least able to follow such a
path.

So you are saying that there really is no such thing as high-end, just a
bunch of crooks trying to rip poor misguided music lovers for their hard
earned money?


Sorry for mixing up specifications and measurements, as you say
yourself,
there are more relevant measurements, than what are used as marketing
arguments today (right?)

Indeed, especially in the high-end audio industry. Your OTL
amplifier is one such glaring example.

There are almost no specifications available for the OTL's, since they
would
not give an objective idea of the end result.

Oh, precisely the opposite, a complete set of performance data
would give a VERY GOOD iobjective dea of the end result. The
manufacturer might not like the picture painted, but it would be
pretty precise.

Again, would you say, from a personal non sceintific point of view, that
OTLs sounds bad and unnatural?


And why is simply eliminating the direct knowledge of what
equipment is playing a hindernace to relaxation? If you HAVE to
know that you are listening to your OTL amplifier in order to
relax, guess, what: YOUR ENJOYMENT ISN'T ABOUT SOUND, IT'S ABOUT
BRAND NAMES!

Absolutely nonsence,

Hardly, if you read your statement.

But your failed to answer the question:

Why is eliminatiung the direct knowledge of what equipment
is playing a hinderance to relaxation?

Please answer that question, as it is at the very root of your
complaints about DB testing.

I have seen DB tests saying that all amplifiers sound the same, and similar
crazy stuff. So from my personal point of view DB test has proven that only
very significant changes in the sound are revealed in these tests.


And if someone makes a claim about the ability to hear a
difference, THEY HAVE ALREADY INTRODUCED THE BASIS OF THE STRESS
IN MAKING THE CLAIM, it could be argued. They have put their
opinion on the line. If a "test" exacerbates the stress, it may
well be because the subject now has doubts as to whether the
original claim is uspportable.

I try to keep an open mind, and are not stoubernly defending any
specific
ideals, brands etc.

But if you HAVE to know what the brand is to relax, which is one
implication of your staement above, then you are NOT keeping an
open mind.

Again, I could not care less about the brand, I only care about enjoying
music the best I can.

Fine, then you why would you have any objections to listening
without having prior knowledge of what you were listening to
equipment-wise?

I do not have any objections at all, however I don't see the point in doing
it. If I did it, the result would be questioned anyway.


All that double blind is asking is that you detect the
difference BASED ON THE SOUND ALONE. That's all. Thus, if you
think that a mass loading puck is going to make a difference and
YOU are interested in seeing if this is the case, all that blind
testing is asking is that you see if you can HEAR the difference
BASED ON THE SOUND ALONE.

If you "know" there is no difference in the sound, would it be likely
that
you would actually hear it?

But you DON'T know there is no difference. Why claim otherwise.
The idea is to see IF you CAN detect a difference by sound
alone. If you can, guess what, there are audibly detectable
differences!

Even, if my imagination only, can change a sound image from being harsh,
to
being pleasing, why not use this tweak?

Then, very simply, it's not about sound. It might be about
perception, but it is about perception in the absebce of the
sonic stimuli to produce the perception. You are perfectly
welcome to use any tweaks for any reason you want, I certainly
don't care.

But the issue comes when someone makes the claim, "it makes a
difference in the SOUND." You just admitted that a tweak may
work on imagination only, so you just stated that, in such a
case IT ISN'T ABOUT THE SOUND.

Why is that stressful?

A test situation is stressful to many people, not all, but many.

You keep asserting this without any data or hypothesis to back
it up.
--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

"Richard D Pierce" wrote in message
...
In article ,
All Ears wrote:
Ohm's Law certainly does apply. I suggest that you read up on it.

The actual force, that the motor of the driver produces, depends on
the
current induced into the coil, right? Does normal speakers have a
totally
flat impedance curve? Assuming that the voltage is kept constant, and
the
inpedance changes, will this not give an unlinear current, which
results
in
amplitude variations over the band? (Rehercing Ohms law

First, what you desribed is NOT Ohm's law.

I replaced resistance with inductance, but the end result will be almost
the
same.

In your case, yes, the end result will be the same: the wrong
answer.

Second your analysis falls WOEFULLY short of anything even
barely adequate to describe how speakers work.

Compromises are made to correct for this issue, but they are compromises.

And they are clearly leading you down the wrong path.

You analysis, for example, predicts that under a constant
current, the speaker MUST, below resonance, have a response
which is independent of frequency, i.e., the speaker does not
roll off. Since it does, your analysis in that region is
incorrect.

Of course it rolls off at some point, I used a simplified model.

But your simplified model predicts that it should NOT roll off,
therefore YOUR MODEL AND ANY CONCLUSIONS DRAWN THEREFROM ARE
WRONG.

Don't yet get this simple yet powerful concept?

Secondly, your analysis predicts that even considering the naive
and simple model of current only, the efficiency at resonance
MUST go down, since the impedance rises at resonance, yet it can
be trivially arranged by non-electrical means that even as the
current goes down, the efficiency and the output of the driver
go UP.

To my knowledge, a typical ported speaker goes down in impedance around
the
port resonance point, and raises in impedance around the cross over
points.
Guess it is a typing error from your side, since the rest of the
statement
seems correct.

Sir, again, with all due respect, you really have absolutely NO
idea what you are talking about. I do not mean this as an
insult, and I do not say it lightly, but in all ernest
honestyand with no malice intended. Your really do not
understand in the most fundamental way how loudspeakers operate.
Your notion of the relation of current and acceleration and such
in loudspeakers is so fundamentally flawed that is is leading
you down a path from which you will be unable to make any sound
predictions of the way a speaker operates.

I may be wrong, if so, I appreciate that nice people like you are able to
guide me down the right path.


Basically, your basic premise is completely flwed because it
simply ignores the fact that speakers are mechncially resonant
devices, that the simple static model you are relying on fails
immediately once you get out of the region of DC exitation
(which, if you sit down and think it through, is the hidden
assumption in your premise).

Be that as it may, speakers which have flat impedance curve get
there by having complex conjugate circuits tto concel the
impedance variations in the drivers. That means that while they
may have a constant current vs frequency profile AS A SYSTEM,
the drivers themselves do not: they STILL have a current that is
frequency dependent on their individual impedance vs frequency
properties. I would suggest that you get your head out of the
"Ohm's Law" hole and start studying Thevenin, Kirchoff and, once
that's under your belt, start studying Thiele and Small.

Variations of transmission line speakers, can obtain a quit flat
impedance
curve, with out complex circuits.

Sorry, my friend, but you arte completely wrong here, I don't
know where you got this notion about the behavior of
transmission lines, but it is simply incorrect in the most
fundamental of ways.

So you would say that it is impossible to build a variation of a
transmission line speaker, that with out complex circuits, does indeed have
a quite flat impedance curve?


It will be very hard to continue a productive conversation
from this point forward if you insist on holding fast to your
understandings of how loudspeakers work. Rather than continue
and have you lead yourself into some very embarrasing dead ends,
I'd rather one of us simply withdraw.

I am not a stoubern person, I can accept if I am wrong about something.


I have to say that this is a clear case where 22 years in a
hi-fi store did not make you an expert on loudspeakers (assuming
I have my attributions correct, I apologize if I have confused
you with someone else), indeed, I am sorry to say and again,
with no intent to insult, you are simply repeating some
ill-founded myths at best.

You confused me with Wylie, whos 22 years experience apparently was not
valid as arguments.


How speakers REALLY work is a deeply fascinating topic, one
which your are SO far from viewing with your current position. I
only hope that at some point you can abandon some of your
ill-founded and technically incorrect views and start to
appreciate how things actually work. It's really quite neat when
the understanding REALLY clicks.

Well, I like understanding how things work, I'll try to find the time to dig
further into the subject.

KE


--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

"Stewart Pinkerton" wrote in message
...
On 27 Jul 2003 22:40:31 GMT, "All Ears" wrote:

"Stewart Pinkerton" wrote in message
...
On 27 Jul 2003 17:39:35 GMT, "All Ears" wrote:

"Stewart Pinkerton" wrote in message
...

Speakers are designed to respond
linearly to a constant voltage input, and most modern speakers
assume
drive by a constant voltage source, i.e. an amp with very low output
impedance and high reserves of current. This is a fair description
of
a good SS amp, but not at all of a tubed OTL amp, which can have
several *ohms* output impedance.

So Ohms law does not apply to speakers, interesting....

Ohm's Law certainly does apply. I suggest that you read up on it.

The actual force, that the motor of the driver produces, depends on the
current induced into the coil, right? Does normal speakers have a totally
flat impedance curve? Assuming that the voltage is kept constant, and the
inpedance changes, will this not give an unlinear current, which results
in
amplitude variations over the band? (Rehercing Ohms law

Your first statement is correct. Almost all commercially available
'hi-fi' speakers have a very non-flat impedance curve. Such speakers
are however designed to have a flat amplitude response with constant
*voltage* input. This does indeed lead to some pretty wild variations
in current, but these are indications of varying efficiency, not
varying amplitude.

Yes, this is of course one of the challanges in serious speaker design.

I will compare the OTLs to a set of SS current amplifiers next week, this
will be interesting.

Good. Be sure to match levels at the speaker terminals, and to do the
test under double-blind protocols, for best results.

Sure
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Mr. Pierce,

I am sorry to have upset you. I wish I could have made myself more clear. I
was not trying to indicate the possibility that color, weight, etc, could
possible make an audible difference. The intent was to point out that since
you
can find two samples of the same model and easily find measurable
differences between them, yet "expert" listeners
will claim they sound identical
that maybe these measured differences (or the level at which they exist)
are not relevant to what people hear. I do not wish to attack measurements
and scientific inquiry as worthless; nor do I wish to attack subjective
listening experience as worthless. However I do feel that the professional
community has not quite reached the point of knowing all there is to know,
and that in the context of listening to high end audio there may be aspects
of reproduced music that are audible but for which measurement techniques
are not yet known or understood.

Wylie Williams

"Richard D Pierce" wrote in message
...
In article XBUUa.141519$GL4.36697@rwcrnsc53,
Wylie Williams wrote:
I keep seeing the following quote:

Further, I can find two samples of the same model and easily
find measurable differences between them, yet "expert" listeners
will claim they sound identical.

I don't know what differences are being referred to. There are all sorts
of
possible differences, like small but measurable variations in color,
weight,
etc., that I think almost everyone would agree are irrelevant to hearing.
Could it be that some of the other small differences that are being
measured
are irrelevant to hearing as well?

What IS it with you people? The principle, despite Mr Wheels
completely boluxed minsinterprations, is simple:

When audible differences are, in fact, shown to exist where
these differences are consistently detectable based on sound
alone, they are ALWAYS accompanied by non-subtle and
consistent differences in measurement of their electrical or
acoustical properties.

This is specifically to refute the common and, frankly,
uninformed myth that there are audible differences while there
are no measurable differences. If you want to add your
ansurdities of color and the likem, that's YOUR choice, and you
have done nothing but confuse the issue.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

----- Original Message -----
From: "Stewart Pinkerton"
Newsgroups: rec.audio.high-end
Sent: Tuesday, July 29, 2003 1:20 AM
Subject: Ears vs. Instruments

On 28 Jul 2003 19:17:34 GMT, "All Ears" wrote:

Yes I think we agree about this point, but I am still wondering how an
OTL
can obtain such a good tonal balance and speaker control with such a high
output impedance,

It cannot and does not (with a nominally flat speaker), you just
*like* that particular combination of amp and speaker.

I am even using 4 ohm speakers, which presents no problem
at all. I would guess that you have listend to a few OTLs yourself, and
could have had the same thoughts.

Quite so. What you are hearing *may* be a serendipitous combination of
a fundamentally inferior amp design and a normally non-flat speaker,
but it's much more likely that you just *like* that sound.

I defenitely like the sound, even if we should go as far as to describe the
amplifier design as inferior. However, Julius Futterman will probably be
spinning in his grave


I'll get some solid state current amplifiers next week, this will be
interesting......

Sir, I believe yo do NOT understand the difference between the
terms "current source" and "voltage source" and, further, you
have a misunderstanding of the operation of loudspeakers, as I
pointed out and hopefully set you on a more correct path in a
different post.

These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source
applies
very well.

No, it doesn't, in fact you are (badly) describing an overall feedback
system which is trying to do an even better job of producing a
constant voltage source. It's not a new technique. Please avoid
getting into excessively deep technical water.

Not talking about the OTLs here, but SS amps equipped with the Anagram power
loop module....


There are almost no specifications available for the OTL's, since they
would
not give an objective idea of the end result.

Oh, precisely the opposite, a complete set of performance data
would give a VERY GOOD iobjective dea of the end result. The
manufacturer might not like the picture painted, but it would be
pretty precise.

I haven't really seen anybody disliking the sound of the few serious OTSs
on
the market, but you may be an exception

Count me in also. BTW, an OTL amp is *not* a 'serious' design......

And why is simply eliminating the direct knowledge of what
equipment is playing a hindernace to relaxation? If you HAVE to
know that you are listening to your OTL amplifier in order to
relax, guess, what: YOUR ENJOYMENT ISN'T ABOUT SOUND, IT'S ABOUT
BRAND NAMES!

Absolutely nonsence,

Hardly, if you read your statement.

But your failed to answer the question:

Even if I close my eyes, the OTLs sound great

No one is arguing with your personal preference, but that's not the
point at issue here, and you know it.

I am exactely talking about my personal preferences...


But the issue comes when someone makes the claim, "it makes a
difference in the SOUND." You just admitted that a tweak may
work on imagination only, so you just stated that, in such a
case IT ISN'T ABOUT THE SOUND.

As a music lover, I am merely reporting observations, not writing
sceintific
reports. I can only encurage people to use their own ears, and judge for
themselves.

So why are you so reluctant to use *only* your ears, without
*knowledge* of which amp is playing?

I don't mind that, but who would consider the results trust worthy anyway?


--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article RhwVa.6614$Oz4.1603@rwcrnsc54,
All Ears wrote:

Frankly, feedback operation, as it applies to audio amplifiers,
is MUCH simpler and, indeed, much more powerful than your
description implies. And, it should be noted, feedback is one of
the most poorly understood concepts by the high-end community
almost as an intrinsic property of the industry. More out-and-
out hooey and bunkum has been promulgated about feedback by
high-end manufacturers, magazine writers and other
self-appointed but clueless experts than almost any other topic.

The SS amplifiers I am talking about are equipped with the Anagram Power
Loop module, and does exactely what I described.....

Well, according to Anagram Technology's website, it's IMPOSSIBLE
to say what it does and how it does it. There is no coherent
description, there is no theory of operation, it simply makes
some cryptic and irrelevant claims, such as "tension gain" and
such that are pretty meaningless.

Until a real technical description of what the thing does
technically, I think any such statement is pure speculation.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

"Wylie Williams" wrote in message


I am sorry to have upset you. I wish I could have made myself more
clear. I was not trying to indicate the possibility that color,
weight, etc, could possible make an audible difference. The intent
was to point out that since you
can find two samples of the same model and easily find measurable
differences between them, yet "expert" listeners will claim they sound
identical
that maybe these measured differences (or the level at which they
exist) are not relevant to what people hear.

That is of course, very true. Test equipment is at least an order of
magnitude more sensitive to differences than ears with very few exceptions.
I can't think of one exception at the moment.

I do not wish to attack
measurements and scientific inquiry as worthless; nor do I wish to
attack subjective listening experience as worthless. However I do
feel that the professional community has not quite reached the point
of knowing all there is to know, and that in the context of listening
to high end audio there may be aspects of reproduced music that are
audible but for which measurement techniques are not yet known or
understood.

I think you'd be amazed at how complete our knowledge of audible differences
are, and how well we can measure them. For example, there are only a very
few things that can go wrong with an audio signal (i.e., there are very few
general kinds of noise and distortion, and they are well-understood, and
well-measured.). This is because an audio signal has only two dimensions,
time and amplitude. Therefore all distortion involves errors in either time
or amplitude or both. BTW everything discussed in this paragraph has been
understood at least mathematically since the late 1920s or early 1930s.
Nothing new along these lines has been discovered or even seriously
hypothesized since then.

What has changed and improved is our ability to measure and characterize
these relatively few well-known forms of noise and distortion. Our ability
to measure them generally exceeds the sensitivity of the ear by a factor of
10 or more.

"All Ears" wrote in message
news:%jwVa.6624$Oz4.1748@rwcrnsc54
"Stewart Pinkerton" wrote in message
...

Your first statement is correct. Almost all commercially available
'hi-fi' speakers have a very non-flat impedance curve. Such speakers
are however designed to have a flat amplitude response with constant
*voltage* input. This does indeed lead to some pretty wild variations
in current, but these are indications of varying efficiency, not
varying amplitude.

Yes, this is of course one of the challanges in serious speaker
design.

It really isn't that much of a challenge. Modern power amplifiers generally
don't have serious problems with most loudspeaker loads. Loudspeaker design
procedures have progressed to the point where there is little or no
justification for making a loudspeaker that is excessively difficult to
drive.

On Tue, 29 Jul 2003 15:28:00 GMT, "All Ears"
wrote:

----- Original Message -----
From: "Stewart Pinkerton"
Newsgroups: rec.audio.high-end
Sent: Tuesday, July 29, 2003 1:20 AM
Subject: Ears vs. Instruments

On 28 Jul 2003 19:17:34 GMT, "All Ears" wrote:

These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source applies
very well.

No, it doesn't, in fact you are (badly) describing an overall feedback
system which is trying to do an even better job of producing a
constant voltage source. It's not a new technique. Please avoid
getting into excessively deep technical water.

Not talking about the OTLs here, but SS amps equipped with the Anagram power
loop module....

Being unfamiliar with this device, I'll simply say that it *cannot*
change a conventional SS amp into a current source - nor should it.

And why is simply eliminating the direct knowledge of what
equipment is playing a hindernace to relaxation? If you HAVE to
know that you are listening to your OTL amplifier in order to
relax, guess, what: YOUR ENJOYMENT ISN'T ABOUT SOUND, IT'S ABOUT
BRAND NAMES!

Absolutely nonsence,

Hardly, if you read your statement.

But your failed to answer the question:

Even if I close my eyes, the OTLs sound great

No one is arguing with your personal preference, but that's not the
point at issue here, and you know it.

I am exactely talking about my personal preferences...

The point at issue is whether you can still hear the 'benefits' of the
OTL amp when you don't *know* that it's connected.

As a music lover, I am merely reporting observations, not writing sceintific
reports. I can only encurage people to use their own ears, and judge for
themselves.

So why are you so reluctant to use *only* your ears, without
*knowledge* of which amp is playing?

I don't mind that, but who would consider the results trust worthy anyway?

Hopefully, you would. Does anyone else's opinion matter to you?
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Tue, 29 Jul 2003 15:22:39 GMT, "All Ears"
wrote:

Again, would you say, from a personal non sceintific point of view, that
OTLs sounds bad and unnatural?

I would say that it sounds inaccurate. Good or bad are matters of
preference.

I have seen DB tests saying that all amplifiers sound the same, and similar
crazy stuff.

No, you have not seen any such claim. You may well have seen claims
that all *well-designed* amplifiers sound the same when used below
clipping, and there's plenty of good evidence to back *that* claim.

So from my personal point of view DB test has proven that only
very significant changes in the sound are revealed in these tests.

The reality, as is well-known to professionals in the fields of audio
and of psychoacoustic research, is that DBTs are the *only* way of
distinguishing extremly subtle - but *real* - sonic differences.

If there was a more sensitive test, then those who design
loudspeakers, amplifiers and codecs for a living would be using it.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article ,
All Ears wrote:
Variations of transmission line speakers, can obtain a quit flat
impedance
curve, with out complex circuits.

Sorry, my friend, but you arte completely wrong here, I don't
know where you got this notion about the behavior of
transmission lines, but it is simply incorrect in the most
fundamental of ways.

So you would say that it is impossible to build a variation of a
transmission line speaker, that with out complex circuits, does indeed have
a quite flat impedance curve?

Yes, as a broad, categorical and technically defnesible
statement, it is indeed impossible to do as you claim. If you
say this because someone told you, then two possibilities exist:

1. The person was simply NOT telling you the truth or,
2. The person is not aware that what he was saying was false.

The frequency-dependent variation in impedance exhibited in
loudspeakers arise from two main sources:

1. Reflection through the electromagnetic system of the motional
(mechanical) impedance of the loudspeaker driver and
enclosure.
2. The voice coil inductance.

The second issue we can dismiss entirely as correctable: the
voice coil inductance arises simply because you have a length of
wire that is generating a magnetic field, energy is being stored
in that field and being reflected back as the fiueld collapses
or increases at a rate proportional to the time dependence of
the input current. There is NOTHING that cabinet loading can do
that wil change that. Absolutely nothing.

The first issue is most relevant and the most interesting anmd
complex source. The motional impedance is essentially the
mechanical analog of electrical impedance and, indeed, the voice
coil and magnet assembly together provide a direct translation
of one to the other by a transformation factor proportional to
the square of the product of the flux density and length of
voice coil wire (Bl^2). It, in fact, works out that mechanical
friction ends up looking EXACTLY like electrical resistance,
mechanical compliance looks exactly like electrical inductance,
and mechanical mass looks exactly like electrical capacitiance.

And, additionally, the enclosure has its own acoustical
impedance characteristics, which, are trabnsformed into
mechanical equivalents by the diaphragm and thus into electrical
terms.

So the ENTIRE impedance curve is the result of electrical (voice
coil), mechanical (driver) and acoustical (enclosure and
radiation load) properties.

Let's look at the mechanical: there are three dominant elements:
the driver's moving mass, the suspension compliance and the
frictional losses in the suspension. The driver mass and
complaiance together form a mechanically resonant system and,
like all such systems (electrical, mechanical, acoustical), it
forms a high impedance at resonance and a low impedance
elsewhere. That's why the ELCTRCIAL impedance is high at
resonance: it's reflecting the high MECHANICAL impedance. And,
we can say, that the lowest the impedance could be is the
electrical resistance of the voice coil. Can't get any lower
than that. ANd the higest it could be depends upon the amount of
mechanical friction in the suspension and the Bl product of the
motor assembly.

ALL drivers have this property NO MATTER WHAT ENCLOSURE THEY ARE
PLACED IN.

Now, at the frequencies of interest, i.e., low frequencies below
100 Hz, where the length of the line is less than 1/2
wavelength, despite what the likes of Bud Fried and others have
claimed, a transmission speaker IS NOT BEHAVING AS A TRUE
TRANSMISSION LINE. It's behaving as if its a large acoustical
inertance (mass) with loss (friction). and ther is a compliance
element to it as well. The result is that the impedance looks
remarkably like a off-tuned vented system.

There is NO physical way that such an enclosure can eliminate
the mechanical mass and compliance effects of the driver itself.
It is simply a physical impossibility. It can modify them by
changing their magnitude and thus the frequency at which they
are happening, but they are still their.

Even if we looked at a theoretically perfect impedance matched
transmission line where the line privides absolutely NO
inetrance or compiance reactance at all and is perfectly lossy,
you will have a system that STILL has the mechnical mass and
compliance of the driver itself, and just has slightly greater
losses. The ONLY effect will be to reduce the Q at resonance
slightly, and you'll end up with an impedance curve that looks
remarkably like the driver's free air impedance.

Anyone who claims to the contrary is either naive or dishonest.

You confused me with Wylie, whos 22 years experience apparently was not
valid as arguments.

No, it is not valid as a claim to expertise.

How speakers REALLY work is a deeply fascinating topic, one
which your are SO far from viewing with your current position. I
only hope that at some point you can abandon some of your
ill-founded and technically incorrect views and start to
appreciate how things actually work. It's really quite neat when
the understanding REALLY clicks.

Well, I like understanding how things work, I'll try to find the time to dig
further into the subject.

Make sure you dig in the right place.
--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

Norman Schwartz wrote:
"Richard D Pierce" wrote:


Face it, the high-end audio industry is DECADES behind behind
the state of the art in many areas, and this is just one
example. I'm not going to give a tutorial on the current range
of available measurements

Measurements haven't led to the construction of great sounding concert
halls, pianos or violins and it appears useful to refer to that which was
done CENTURIES ago.

but measurement of the old instruments seems to have produced some results.

see

http://abcnews.go.com/sections/scite...ard010328.html

and similar sites.

--
-S.

S888Wheel wrote:
Dick said

Mr. Wheel, Dick said one thing, Your paraphrasing of what Dick
said is something else entirely. I should know. I am Dick.

Please do NOT use YOUR paraphrasing of what I have said as a
substitute for what I actually said. You have demonstrated in
this thread you are not very good at it.

Thank you.

--
| Dick Pierce |
| Professional Audio Development |

What are you talking about?

Again, it seems pretty clear to me: he thinks you
are misundestanding and misrepresenting what he said.

--
-S.

Wylie Williams wrote:
Mr. Pierce,

I am sorry to have upset you. I wish I could have made myself more clear. I
was not trying to indicate the possibility that color, weight, etc, could
possible make an audible difference. The intent was to point out that since
you
can find two samples of the same model and easily find measurable
differences between them, yet "expert" listeners
will claim they sound identical
that maybe these measured differences (or the level at which they exist)
are not relevant to what people hear. I do not wish to attack measurements
and scientific inquiry as worthless; nor do I wish to attack subjective
listening experience as worthless. However I do feel that the professional
community has not quite reached the point of knowing all there is to know,
and that in the context of listening to high end audio there may be aspects
of reproduced music that are audible but for which measurement techniques
are not yet known or understood.

In other words you believe that the 'common, uninformed
myth' that Dick cites below, may nto be a myth. What evidence would you
put forward to suggest that it isn't a myth?

This is specifically to refute the common and, frankly,
uninformed myth that there are audible differences while there
are no measurable differences.

--
-S.

"chung" wrote in message
...
All Ears wrote:


Even if I close my eyes, the OTLs sound great


My youngest son always thinks that music sounds better when the bass and
treble controls are boosted. To him, the music is much more alive and
dynamic that way.

The point is that having a not-flat frequency response can be euphonic.
A small boost in the mid-range can make human voices more pleasant, and
certain harmonic distortions can make some instruments sound fuller.

The other thing to keep in mind is that if one amp sounds different than
all others, while all the others sound very similar among themselves,
there is high probability that the one that sounds different is not
accurate.

We all have our preferences in how we like music presented, we must not
forget that the most important thing is to enjoy listening to music, that is
what it is all about.

KE

"Wylie Williams" wrote in message
t...
However I do feel that the professional
community has not quite reached the point of knowing all there is to know,
and that in the context of listening to high end audio there may be aspects
of reproduced music that are audible but for which measurement techniques
are not yet known or understood.

Mr. Williams, perhaps this is because you do not know what the
professionals know. Indeed, as has been said often before, the
high-end audio realm is far behind and so self-isolated from
the current state of the art in a wide array of topics. One area
of note in this respect is many in the high-end make grand
sweeping dogmatic declarations about the properties of human
hearing that have decades ago been studied to death and
refuted.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

Well, if I read the preceding posts correctly I must suppose that
everything that ever is to be known about human auditory perception is
known. And maybe the same for audio component measurement.
I have a question - Where can I find a list of those components that
have been shown to be good enough that the human ear cannot detect
improvement? Or if not a list, a chart of the specifications?

Wylie Williams

"All Ears" wrote in message
news:4owVa.6648$Oz4.2072@rwcrnsc54

Not talking about the OTLs here, but SS amps equipped with the
Anagram power loop module....

Which raises the issue of what Anagram's technology is.

The answer should lie at http://www.anagramtech.com .

Curiously the description of their company's technology at
http://www.anagramtech.com/base/haut.html
does not seem to include any discussion of the power loop module, despite a
conspicuous picture of said module.

Here's quotes of a a few sentences from near the top of the page at
http://www.anagramtech.com/base/haut.html

"The RE24 process raises 20 bit data streams to 24 bit resolution and 16 bit
data streams to 20 bit resolution."
This would be the audio equivalent of perpetual motion. Nothing but!

" RE24 shifts the truncation noise out of the audible band."

This is feasible and routinely done with established technology that is in
the public domain.

"However, unlike usual noise-shaping techniques, the RE24 process adds an
algorithmically generated noise in the upper part of the spectrum."

Adding an algorithmically-generated noise in the upper part of the spectrum
is *exactly* what conventional noise-shaping does.

"As the process is not correlated with the incoming signal, it is free of
intermodulation distortion."

Adding an algorithmically-generated noise in the upper part of the spectrum
that is not correlated with the incoming signal is *exactly* what
conventional noise-shaping does.

Conventional noise-shaping is free of intermodulation distortion, as well.

So there you have it. AFAIK Anagram Technologies proposes to deliver both
the audio equivalent of perpetual motion and exactly the same things that
the established technology they propose to upgrade already provides.

The rest of the web page is equally enlightening.

Why is the phrase "snake oil" running through my mind?

CD players like the Audio Aero Capitole and others using the Anagram
S.T.A.R.S. module, seems to be doing quite well. I have no experiences with
the rest of their modules yet.
You are right, their web page contains little relevant information. It could
be that they are holding the deck close to the body towards the competition.

KE

"Arny Krueger" wrote in message
t...
"All Ears" wrote in message
news:4owVa.6648$Oz4.2072@rwcrnsc54

Not talking about the OTLs here, but SS amps equipped with the
Anagram power loop module....

Which raises the issue of what Anagram's technology is.

The answer should lie at http://www.anagramtech.com .

Curiously the description of their company's technology at
http://www.anagramtech.com/base/haut.html
does not seem to include any discussion of the power loop module, despite
a
conspicuous picture of said module.

Here's quotes of a a few sentences from near the top of the page at
http://www.anagramtech.com/base/haut.html

"The RE24 process raises 20 bit data streams to 24 bit resolution and 16
bit
data streams to 20 bit resolution."
This would be the audio equivalent of perpetual motion. Nothing but!

" RE24 shifts the truncation noise out of the audible band."

This is feasible and routinely done with established technology that is
in
the public domain.

"However, unlike usual noise-shaping techniques, the RE24 process adds an
algorithmically generated noise in the upper part of the spectrum."

Adding an algorithmically-generated noise in the upper part of the
spectrum
is *exactly* what conventional noise-shaping does.

"As the process is not correlated with the incoming signal, it is free of
intermodulation distortion."

Adding an algorithmically-generated noise in the upper part of the
spectrum
that is not correlated with the incoming signal is *exactly* what
conventional noise-shaping does.

Conventional noise-shaping is free of intermodulation distortion, as well.

So there you have it. AFAIK Anagram Technologies proposes to deliver both
the audio equivalent of perpetual motion and exactly the same things that
the established technology they propose to upgrade already provides.

The rest of the web page is equally enlightening.

Why is the phrase "snake oil" running through my mind?

"Wylie Williams" wrote in message news:PU%Va.23636$uu5.2909@sccrnsc04...
Well, if I read the preceding posts correctly I must suppose that
everything that ever is to be known about human auditory perception is
known. And maybe the same for audio component measurement.

Well, perhaps you must suppose that in order to maintain your
unsubstantiated beliefs. But saying we know how amplifiers work is not
the same as saying we know everything that will ever be known about
electrical engineering.

One thing we do know is that we can already measure much better than
we can hear. So just what new knowledge are you hoping for?

I have a question - Where can I find a list of those components that
have been shown to be good enough that the human ear cannot detect
improvement? Or if not a list, a chart of the specifications?

You can't. As I think you and I know others have noted, no one has any
financial incentive to test available consumer gear. And, as has also
been made clear here recently, "specifications" often don't mean
squat. You'll just have to rely on general principles, I'm afraid.
That, or do your own DBTs. You've done some, I trust. What have you
found?

bob

"Arny Krueger" wrote in message
news:M4KVa.17391$YN5.18292@sccrnsc01...
"All Ears" wrote in message
news:%jwVa.6624$Oz4.1748@rwcrnsc54
"Stewart Pinkerton" wrote in message
...

Your first statement is correct. Almost all commercially available
'hi-fi' speakers have a very non-flat impedance curve. Such speakers
are however designed to have a flat amplitude response with constant
*voltage* input. This does indeed lead to some pretty wild variations
in current, but these are indications of varying efficiency, not
varying amplitude.

Yes, this is of course one of the challanges in serious speaker
design.

It really isn't that much of a challenge. Modern power amplifiers
generally
don't have serious problems with most loudspeaker loads. Loudspeaker
design
procedures have progressed to the point where there is little or no
justification for making a loudspeaker that is excessively difficult to
drive.

As a note to this, I will say that I had some interesting experiences with a
set of B&W DM 604 S3. These speakers were supposed to be relatively
efficient, however I tried to "max them out" and their performance just kept
increasing with the amplifier power. I ended up with some 800W in 8 ohm
monoblocks. Of course it was a bit of a crazy experiment to have equipment
10 times the value of these speakers behind them, but it did show how hungry
for power these speakers really are. Anyway, I will still say that the value
for money in these speakers are quite good.

KE

"Richard D Pierce" wrote in message
news:xWGVa.15186$Ho3.2577@sccrnsc03...
In article RhwVa.6614$Oz4.1603@rwcrnsc54,
All Ears wrote:

Frankly, feedback operation, as it applies to audio amplifiers,
is MUCH simpler and, indeed, much more powerful than your
description implies. And, it should be noted, feedback is one of
the most poorly understood concepts by the high-end community
almost as an intrinsic property of the industry. More out-and-
out hooey and bunkum has been promulgated about feedback by
high-end manufacturers, magazine writers and other
self-appointed but clueless experts than almost any other topic.

The SS amplifiers I am talking about are equipped with the Anagram Power
Loop module, and does exactely what I described.....

Well, according to Anagram Technology's website, it's IMPOSSIBLE
to say what it does and how it does it. There is no coherent
description, there is no theory of operation, it simply makes
some cryptic and irrelevant claims, such as "tension gain" and
such that are pretty meaningless.

Until a real technical description of what the thing does
technically, I think any such statement is pure speculation.

The description is given to me from a source close to Anagram, so I have no
reason to doubt the function.

However I agree, that the technical description is quite sparse. Anyway,
I'll get the chance to evaluate the end result soon. As usual, I will try to
be as objective as possible


--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

"Richard D Pierce" wrote in message
t...
In article 4owVa.6648$Oz4.2072@rwcrnsc54,
All Ears wrote:
Quite so. What you are hearing *may* be a serendipitous combination of
a fundamentally inferior amp design and a normally non-flat speaker,
but it's much more likely that you just *like* that sound.

I defenitely like the sound, even if we should go as far as to describe
the
amplifier design as inferior. However, Julius Futterman will probably be
spinning in his grave

And the Futterman is one example of an OTL tube amplifier I have
evaluated and, indeed, the output impedance is quite high.

The Futtermam designs suffered from some obvious design compromises, the far
best speaker match was the Quad electrostates.


No one is arguing with your personal preference, but that's not the
point at issue here, and you know it.

I am exactely talking about my personal preferences...

Fine, and no one is arguing with your personal preference, and
is also why my personal preference is irrelevant as well. We are
speaking to the topic of the performance of systems and why one
combination TECHNICALLY works one way and why another works
differently.

So why are you so reluctant to use *only* your ears, without
*knowledge* of which amp is playing?

I don't mind that, but who would consider the results trust worthy
anyway?

Because if it's all about SOUND, then the ONLY way to find
things out is to use your EARS ONLY. Otherwise, it's not about
sound.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

"Stewart Pinkerton" wrote in message
news:O7KVa.16563$Ho3.3573@sccrnsc03...
On Tue, 29 Jul 2003 15:28:00 GMT, "All Ears"
wrote:

----- Original Message -----
From: "Stewart Pinkerton"
Newsgroups: rec.audio.high-end
Sent: Tuesday, July 29, 2003 1:20 AM
Subject: Ears vs. Instruments

On 28 Jul 2003 19:17:34 GMT, "All Ears" wrote:

These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source
applies
very well.

No, it doesn't, in fact you are (badly) describing an overall feedback
system which is trying to do an even better job of producing a
constant voltage source. It's not a new technique. Please avoid
getting into excessively deep technical water.

Not talking about the OTLs here, but SS amps equipped with the Anagram
power
loop module....

Being unfamiliar with this device, I'll simply say that it *cannot*
change a conventional SS amp into a current source - nor should it.

And why is simply eliminating the direct knowledge of what
equipment is playing a hindernace to relaxation? If you HAVE to
know that you are listening to your OTL amplifier in order to
relax, guess, what: YOUR ENJOYMENT ISN'T ABOUT SOUND, IT'S ABOUT
BRAND NAMES!

Absolutely nonsence,

Hardly, if you read your statement.

But your failed to answer the question:

Even if I close my eyes, the OTLs sound great

No one is arguing with your personal preference, but that's not the
point at issue here, and you know it.

I am exactely talking about my personal preferences...

The point at issue is whether you can still hear the 'benefits' of the
OTL amp when you don't *know* that it's connected.

Yes, no doubt about this, there is a significant change in the sound image
with the OTLs compared to any SS design. More bloom in the midrange, and the
bass works extremely well in the bottom octaves.


As a music lover, I am merely reporting observations, not writing
sceintific
reports. I can only encurage people to use their own ears, and judge
for
themselves.

So why are you so reluctant to use *only* your ears, without
*knowledge* of which amp is playing?

I don't mind that, but who would consider the results trust worthy
anyway?

Hopefully, you would. Does anyone else's opinion matter to you?

I always listen to others opinions, but do not necessarily agree. I do my
best to keep an open mind.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Richard D Pierce" wrote in message
...
In article ,
All Ears wrote:
Beyond that, I am not saying that the result is "bad and
unnatural," That's a judgement I will not make because it is a
preferential thing.

I am refuting your claim that such an amplifier could ever
possibly measure even remotely the same. My argument is not
whether the result saound good or bad, that's your decision to
make. My argument is to directly challenge your claim that this
amplifier could measure like any other IN SITU: they can't, it's
as simple as that.

Thus, your premise, or your question, as the case may be, "how
can two amplifier that have similar specs sound so different" is
is meaningless in the face of the fact that two such amps SIMPLY
CAN'T HAVE SIMILAR SPECS.

Do you understand the point?

Yes I think we agree about this point,

It is clear to me we do not, because I feel you are still
laboring under a set of fundamental misunderstandings qbout how
things work.

but I am still wondering how an OTL
can obtain such a good tonal balance and speaker control with such a high
output impedance,

I did NOT say "good" or "bad." I said, in direct refutation of
your point, that they cannot measure the same. Thus your premise
that "they measure the same but sound different" is entirely
refuted on its face.

I am even using 4 ohm speakers, which presents no problem
at all.

BY this statement alone, it is clear to me you do not understand
the technical imlications of the issue of OTL output impedance,
because it is more significant with 4 ohm speaker than with 8
ohm speakers.

The OTLs are designed to work with speakers down to 3 ohm...


I would guess that you have listend to a few OTLs yourself, and
could have had the same thoughts.

Why would you assume so?

Actually, the speakers I use are all designed by tube lovers,

A comment on this: there are really VERY few really competent
speaker designers. Just being a lover of tubes does not qualify
one to design speakers for them.

Of course, but the one does not rule out the other. Would you name a few
speaker designers, that you consider competent?


Sir, I believe yo do NOT understand the difference between the
terms "current source" and "voltage source" and, further, you
have a misunderstanding of the operation of loudspeakers, as I
pointed out and hopefully set you on a more correct path in a
different post.

These amplifiers monitors the impedance at the speaker terminals, and
adjusts the feed back loop accordingly, so the term current source
applies
very well.

No, it os no ABUNDANTLY clear that your do not understand the
meaning of the term "current source" or "voltage source." It has
NOTHING to do with what you are desribing, which, by the way,
you are not describing correctly anyway.

The DEFINITION of a current source is very simple: a current
source is one whose effective Thevenin source impedance is
substantially larger than the load impedance. A voltage source
os one whose effective Thevenin source impedance is
substantially smaller than the load impedance. Period. All the
other hooey and hoopla and handwaving is nonsense.

And the result is real simple: driving a frequency dependent
load impedance from a current source will ALWAYS result in the
imposition of frequency response variations on the output of
that source and thus on the system as a whole in a way that is a
function of the load impedance.

Period. This is not some narrow-minded high-end agenda-driven
pseudo-definition, this is a precise technical description of
the physical behavior of the system.

It should be possible to find a few serious manufactures in the industry,
anyway, a standard would give a goal to persue for the serious ones. It
could be implemented like the ISO or similar standard.

You missed the point, the standard ALREADY exist: it is the
high-end audio industry that is most guilty of egregious
violations of these standards. The high-end industry seems also
to be the least technically competent to follow such standards.

There are almost no specifications available for the OTL's, since they
would
not give an objective idea of the end result.

Oh, precisely the opposite, a complete set of performance data
would give a VERY GOOD iobjective dea of the end result. The
manufacturer might not like the picture painted, but it would be
pretty precise.

I haven't really seen anybody disliking the sound of the few serious OTSs
on
the market, but you may be an exception

Excuse me, sir, that is NOT what I said, and that is NOT the
questyion you posed. You stated:

"There are almost no specifications available for the OTL's,
since they would not give an objective idea of the end
result."

And my refutation is that such specification, properly done,
would precisely lead to and exact idea of their objective
performance. You may like listening to the result. You may not.

But when, sir did I say, at ANY point, whether I did or did not
LIKE the result? (Hint: I never did and I object to you claiming
otherwise.)

Absolutely nonsence,

Hardly, if you read your statement.

But your failed to answer the question:

Even if I close my eyes, the OTLs sound great

You failed to answer the question yet again. Methinks you cannot
answer the question.

Why is eliminatiung the direct knowledge of what equipment
is playing a hinderance to relaxation?

Please answer that question, as it is at the very root of your
complaints about DB testing.
As a music lover, I am merely reporting observations, not writing
sceintific
reports. I can only encurage people to use their own ears, and judge for
themselves.

But, if you KNOW the brand, if you KNOW what wires and what
amplifiers, guess what YOU AREN'T JUST USING YOUR EARS!

You are contradicting yourself: you say for people to trust
their ears and then you tell them not to.

--
| Dick Pierce |
| Professional Audio Development |
| 1-781/826-4953 Voice and FAX |
| |

On Thu, 31 Jul 2003 15:14:43 GMT, "All Ears"
wrote:

"Stewart Pinkerton" wrote in message
news:Y7KVa.16733$o%2.10872@sccrnsc02...
On Tue, 29 Jul 2003 15:22:39 GMT, "All Ears"
wrote:

Again, would you say, from a personal non sceintific point of view, that
OTLs sounds bad and unnatural?

I would say that it sounds inaccurate. Good or bad are matters of
preference.

Are you speaking from personal experiences, or theoretical judgement?

I've heard the Futterman, and I wasn't impressed. Also, they are
theoretically disastrous, which is a bad place to start, IME!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Thu, 31 Jul 2003 15:15:24 GMT, "All Ears"
wrote:

"Stewart Pinkerton" wrote in message
news:O7KVa.16563$Ho3.3573@sccrnsc03...

The point at issue is whether you can still hear the 'benefits' of the
OTL amp when you don't *know* that it's connected.

Yes, no doubt about this, there is a significant change in the sound image
with the OTLs compared to any SS design. More bloom in the midrange, and the
bass works extremely well in the bottom octaves.

Excuse me, that does not answer the question. Have you compared this
amp with something else in a level-matched *blind* test?

I always listen to others opinions, but do not necessarily agree. I do my
best to keep an open mind.

The trick is to do this while avoiding your brain falling out! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
news:PQlWa.36487$uu5.4559@sccrnsc04...
On Thu, 31 Jul 2003 15:14:43 GMT, "All Ears"
wrote:

"Stewart Pinkerton" wrote in message
news:Y7KVa.16733$o%2.10872@sccrnsc02...
On Tue, 29 Jul 2003 15:22:39 GMT, "All Ears"
wrote:

Again, would you say, from a personal non sceintific point of view,
that
OTLs sounds bad and unnatural?

I would say that it sounds inaccurate. Good or bad are matters of
preference.

Are you speaking from personal experiences, or theoretical judgement?

I've heard the Futterman, and I wasn't impressed. Also, they are
theoretically disastrous, which is a bad place to start, IME!

Modern OTLs has fortunately solved some issue present in the Futterman
design. I think you would change your mind if you listened to some Tenor,
Atma-Sphere or Joule Electra OTLs, with the right speakers.

I have had quite a few ears to listen to the OTLs lately and they are all
extremely impressed by how truely natural they sound......

KE

--

Stewart Pinkerton | Music is Art - Audio is Engineering