Bypassing caps? How about with wire?

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"TonyP" <TonyP@optus.net.com.au> wrote in message
news:4118a8e8$0$6942$afc38c87@news.optusnet.com.au

> "Scott Dorsey" <kludge@panix.com> wrote in message
> news:cf80hm$7r9$1@panix2.panix.com...

>> As I pointed out to Phil, it's entirely possible to get insanely low
>> top octave THD values with standard measurement procedures because
>> all of the harmonics being generated are outside of the passband of
>> the measuring device.

Agreed. The third harmonic of 7.4 KHz and up, as well as the second
harmonic of 11.1 KHz and up get lost in the reconstruction filter, if not
the anti-aliasing filter.

> This is a very common way for manufacturers to cook the numbers.

Agreed, but people who want to accurately characterize nonlinearities can
uncook the books in the same context with multitone measurements.

One of the most flexible tests I know of is what I call an empty well test.
One drives the UUT with a multitone (or music) that has groups of missing
tones or filter notches that create empty wells. The wells will start
filling up in the presence of a wide variety of different kinds of
nonlinearities. Nevertheless, not all kinds of nonlinear distortion will add
significantly to the wells - see below.

> Who, apart from you, mentioned only measuring the 10k-20k band. It is
> very selective to choose ONE octave and ignore the other NINE. Treble
> starts below 10kHz in my book.

Focus on the top octave is, IME not about misapprehensions.

(1) Audio gear tends to be more nonlinear as frequency goes up - in the
analog domain open loop gain goes down, and digital filters are more prone
to clipping near the stop band.

(2) Over the years musical program material seems to have tended towards
stronger content in the top octave(s).

(3) Because of Fletcher-Munson effects and masking, signals in the top
octave are less likely to be heard. This means that they are less likely to
distract listeners from any cross-modulation effects they stimulate when it
intermodulates down into the lower octaves.

When I talk about reliably hearing 0.1 % nonlinear distortion, I'm
specifically thinking of natural sounds with lots of energy in the top
octave, and less, little or no energy in the range where the ear is most
sensitive - 2-6 KHz. If there are common kinds of audible nonlinearity in
the upper octave, it will be heard with this test. This is especially true
of clipping - relatively tiny amounts of clipping can be heard under these
conditions.

Since I'm flogging Doppler distortion in another thread another group, I'm
compelled to point out that all of the *wonderful* tests I've described are
pretty much blind to Doppler distortion. The good news is that while Doppler
distortion is real and present in loudspeakers, it's also almost always
quite a bit less than the AM distortion that generally dumps quite a bit of
energy at exactly the same frequencies. This AM distortion is generally
heard and measured with the listening and technical tests I've been talking
about.

 

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TonyP <TonyP@optus.net.com.au> wrote:
>"Scott Dorsey" <kludge@panix.com> wrote in message
>> As I pointed out to Phil, it's entirely possible to get insanely low
>> top octave THD values with standard measurement procedures because all
>> of the harmonics being generated are outside of the passband of the
>> measuring device. This is a very common way for manufacturers to cook
>> the numbers.
>
>Who, apart from you, mentioned only measuring the 10k-20k band. It is very
>selective to choose ONE octave and ignore the other NINE. Treble starts
>below 10kHz in my book.

Nobody did. One person was talking about getting really good numbers.
I gave an example of how to get really good numbers. If you want nice
numbers and you don't care how they correlate with actual sound quality,
there are all sorts of wonderful things you can do.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

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> One of the most flexible tests I know of is what I call an "empty-well"
> test. One drives the UUT with a multitone (or music) that has groups
> of missing tones or filter notches that create empty wells. The wells
> will start filling up in the presence of a wide variety of different kinds
> of nonlinearities.

I've been arguing in favor of such testing for a long time -- it's a good way to
spot anharmonic distortion IN ACTUAL PROGRAM MATERIAL (as opposed to test
tones). But no one wants to listen.


> Nevertheless, not all kinds of nonlinear distortion
> will add significantly to the wells - see below.

Haven't had my Wheaties yet. I didn't see anything below that described what
sorts of distortions did and did not "fill the wells." Could you expand?

 

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In article <e6edncvtD_ChVIXcRVn-uQ@comcast.com> arnyk@hotpop.com writes:

> > This is a very common way for manufacturers to cook the numbers.
>
> Agreed, but people who want to accurately characterize nonlinearities can
> uncook the books in the same context with multitone measurements.

But this means they have to make their own measurements (or rely on
others such as you). That's always a good thing to do for acacemic
reasons, but as long as they have it long enough to measure it, they
might as well listen to it, too.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

 

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"William Sommerwerck" <williams@nwlink.com> wrote in message
news:10hhisrhbg7a745@corp.supernews.com
>> One of the most flexible tests I know of is what I call an
>> "empty-well" test. One drives the UUT with a multitone (or music)
>> that has groups of missing tones or filter notches that create empty
>> wells. The wells will start filling up in the presence of a wide
>> variety of different kinds of nonlinearities.

> I've been arguing in favor of such testing for a long time -- it's a
> good way to spot anharmonic distortion IN ACTUAL PROGRAM MATERIAL (as
> opposed to test tones). But no one wants to listen.

Not exactly no-one:

http/www.dlcdesignaudio.com/products/files/ms06ptf.doc

This paper about the PTF system is kinda skimpy on the details, but I can
tell you that the maximum SPL test is based on an empty well test. People
have been talking about doing this sort of thing for decades, but its one of
those things that AFAIK never seemed to show up in print or as part of a
standard.

BTW, The PTF system is a big seller, relatively speaking in Detroit. At
least two of the big 3 car makers have figured out that a $40,000 SUV with a
broken or substandard radio and CD player is a broken SUV from the
perspective of many buyers. Due to production changes, model proliferation,
changeover years and etc. some project engineers end up designing upwards of
12 multichannel speaker systems per year. An effective automated tool that
correlates well with the responses of trained listeners and general
consumers has a market in Detroit. Some of the audio systems that rank most
highly in Powers consumer satisfaction surveys uhh, err, emm, ahem, do well
in PTF tests, if you catch my drift.

BTW, empty well test results are IME significant with perceptual coders.

>> Nevertheless, not all kinds of nonlinear distortion
>> will add significantly to the wells - see below.

> Haven't had my Wheaties yet. I didn't see anything below that
> described what sorts of distortions did and did not "fill the wells."
> Could you expand?

Yes - Doppler distortion creates sidebands that are very close to the
components of the program material. They don't spill appreciably into the
empty wells.

 

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> Not exactly no-one:

> http/www.dlcdesignaudio.com/products/files/ms06ptf.doc

Do you have another source for this? It's completely illegible on my screen.


> BTW, empty well test results are IME significant with perceptual coders.

Not at all surprising.


> Yes - Doppler distortion creates sidebands that are very close to the
> components of the program material. They don't spill appreciably into the
> empty wells.

It is also true that you can't generate sidebands for signals that have been
removed.

 

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"William Sommerwerck" <williams@nwlink.com> wrote in message
news:10hhlgskusos323@corp.supernews.com
>> Not exactly no-one:
>
>> http/www.dlcdesignaudio.com/products/files/ms06ptf.doc

> Do you have another source for this? It's completely illegible on my
> screen.

It seems to improve if you cut and paste it into some other text editing
program.

Here's the relevant paragraph:

"The maximum SPL test uses a specific test signal and analysis to determine
the maximum acoustic output of a sound system. Ultimately, a single SPL
number is read from a calibrated microphone.

"The test signal is noise-like with a defined spectrum and a defined crest
factor. Both mimic highly compressed and slightly clipped broad-band music.
The acoustic output is analyzed for compression in any 1/3 octave band and
for distortion products created by non-linearities in the audio system. The
system gain is increased until a defined limit for either is reached. SPL
at that time is taken and reported as maximum SPL.

>> BTW, empty well test results are IME significant with perceptual
>> coders.
>
> Not at all surprising.

>> Yes - Doppler distortion creates sidebands that are very close to the
>> components of the program material. They don't spill appreciably
>> into the empty wells.

> It is also true that you can't generate sidebands for signals that have
been removed.

Generally not a problem if the wells are reasonably narrow. Nonlinearity is
generally not isolated. If something is nonlinear at 20 KHz, its usaully
still somewhat nonlinear at 15 KHz. If something is nonlinear at 20 Hz, its
usually still somewhat nonlinear at 50 Hz.

 

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In article <2ngpeiFnhk0U1@uni-berlin.de>,
"Phil Allison" <philallison@tpg.com.au> wrote:

> "Monte McGuire"
>
> > I usually use a measurement bandwidth for THD+N that allows for
> > harmonics above 20KHz, since nonlinearities up there could also manifest
> > themselves as IMD, not just as harmonics that are inaudible. So, that's
> > why I suggested that your .003% number might be mostly noise.
>
>
> ** Do a test - see that it is not.

OK, so your TL07x produces a lot more distortion when handling very
simple pure tones of low frequency than other more modern amps produce.
Great. We agree now; wasn't that my original contention? I wonder what
all of the huffing and puffing is about. Do you have to disagree at all
costs, even when we actually agree? Why is that?

> > But, if .003% is specified with a tight bandwidth, then maybe it really
> > is all distortion and the TL072 really does make hash out of signals
> > like I originally proposed.
>
>
> ** Where did you get the ridiculous idea that anyone can hear 0.003% THD
> of any signal ????

I don't particularly care about that _specifically_, but I do know that
unless a device makes less distortion than another device, it cannot be
considered cleaner than the other device. In other words, even though
we may not be able to hear the errors that were directly measured, there
may be other errors of a much larger magnitude (and are thus audible)
that are generated with real world signals that arise from the same
mechanisms that created the errors observed when handling the test
signals.

Sure, the .0000whatever percent distortion handling a pure tone may not
be audible. What happens with real music and complex sounds? You
cannot honestly say, and for some reason that I do not understand, you
DBT folks like to assure that your equipment is proven to be as close to
mediocre as possible with all the test signals you care to listen to.

Why not have a little extra performance in your system? What would be
so bad about that? It might actually sound better in some situation
that you didn't have the time or foresight to construct a DBT to
specifically screen against. I'm honestly trying to find out exactly
what the savings are of having optimally bad performing gear, stuff that
has weaknesses, but which are just below our threshold of perception.
Can you assure that all possible combinations of such gear still have
shortcomings that are still inaudible? Again, what's the big savings?
And how do you know that in every situation, your gear isn't causing
audible problems? Do you ever listen in an uncontrolled manner, or is
everything a DBT???


Monte McGuire
monte.mcguire@verizon.net

 

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"Monte McGuire" <monte.mcguire@verizon.net> wrote in message
news:monte.mcguire-6B2C4B.01194511082004@news.verizon.net
> In article <2ngpeiFnhk0U1@uni-berlin.de>,
> "Phil Allison" <philallison@tpg.com.au> wrote:

>> ** Where did you get the ridiculous idea that anyone can hear
>> 0.003% THD of any signal ????

> I don't particularly care about that _specifically_,

Well you shouldn't, since the threshold of audiblity is closer to 0.1%
Note, there's a 33:1 ratio between 0.1 and 0.003 .

> but I do know
> that unless a device makes less distortion than another device, it
> cannot be considered cleaner than the other device.

This leads to an endless search for smaller numbers for the sake of smaller
numbers.

> In other words,
> even though we may not be able to hear the errors that were directly
> measured, there may be other errors of a much larger magnitude (and
> are thus audible) that are generated with real world signals that
> arise from the same mechanisms that created the errors observed when
> handling the test signals.

That's why we don't try to build equipment with as close to 0.1% distortion
as possible.


> Sure, the .0000whatever percent distortion handling a pure tone may
> not be audible. What happens with real music and complex sounds?

That's knowable and known. Depends on which music and which complex sounds.
But, with an approximate 33:1 safety margin...

> You cannot honestly say,

Sure we can. We can do technical tests and listening tests and see what
happens.

>and for some reason that I do not understand, you
> DBT folks like to assure that your equipment is proven to be as close
> to mediocre as possible with all the test signals you care to listen to.

I wouldn't call 33:1 safety margin "as close to mediocre as possible". Why
would you do that?

> Why not have a little extra performance in your system?

Isn't 33:1 enough extra performance?

> What would be so bad about that?

What is so bad about having a 33:1 margin for error?

> It might actually sound better in some situation
> that you didn't have the time or foresight to construct a DBT to
> specifically screen against.

At some point, enough is enough. 0.003% is not the modern limit, the modern
limit is more like 0.00015%. That's another 20x safety margin for a total of
660:1. Apparently, that's still not enough for you, Monte!

> I'm honestly trying to find out exactly
> what the savings are of having optimally bad performing gear, stuff
> that has weaknesses, but which are just below our threshold of
> perception.

Since when is 33:1 or 660:1 reserve performance "just below our threshold of
perception"?

>Can you assure that all possible combinations of such
> gear still have shortcomings that are still inaudible?

If you're talking 33:1 or 660:1 reserve performance, the answer has to be
yes.

> Again, what's the big savings?

What's wrong with recognizing that we play that DAC with 0.00015% THD
through speakers with 0.1 to 1.0 to 10% THD, depending on what frequency in
the audio range you are talking about, and instead throwing our efforts into
fixing that speaker with 10% THD?

>And how do you know that in every situation, your
> gear isn't causing audible problems?

Which gear? In this corner I have a DAC with 0.00015% THD, and in this
corner I have a speaker with 10% THD, both within the 20-20 KHz range. Monte
seems to be saying "forget the speaker and continue to spend time and money
improving that DAC".

>Do you ever listen in an uncontrolled manner, or is everything a DBT???

What's so sacred about listening in an uncontrolled manner? Isn't it true
that uncontrolled listening got us into this sitatuion where Monte McGuire
is ranting and raving about 0.003% distortion being "just below our
threshold of perception", while his speakers still have 10% THD?

If 0.003% distortion is "just below our threshold of perception", what is
10% distortion? Your monitoring system has both. Which should be fixed
first?

 

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On Wed, 11 Aug 2004 05:19:45 GMT, Monte McGuire
<monte.mcguire@verizon.net> wrote:

> Do you ever listen in an uncontrolled manner, or is
>everything a DBT?

And "manner of listening" is the grizzly bear sitting over
in the corner. Speak softly...

Chris Hornbeck

 

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"Scott Dorsey"
> TonyP
> >"Scott Dorsey"

> >> As I pointed out to Phil, it's entirely possible to get insanely low
> >> top octave THD values with standard measurement procedures because all
> >> of the harmonics being generated are outside of the passband of the
> >> measuring device. This is a very common way for manufacturers to cook
> >> the numbers.
> >
> >Who, apart from you, mentioned only measuring the 10k-20k band. It is
very
> >selective to choose ONE octave and ignore the other NINE. Treble starts
> >below 10kHz in my book.
>
> Nobody did.


** Yes YOU did by claiming your own speakers had less high frequency
"hash" than a TL071.


> One person was talking about getting really good numbers.


** Blatant lie.



> I gave an example of how to get really good numbers.


** But falsely claimed it was standard technique.


> If you want nice numbers and you don't care how they correlate with actual
sound quality,
> there are all sorts of wonderful things you can do.


** Yep - tell blatant lies like that failed tape recorder mechanic Scott
Dorsey.




................... Phil

 

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Phil Allison <philallison@tpg.com.au> wrote:
>
>** Yes YOU did by claiming your own speakers had less high frequency
>"hash" than a TL071.

I was pointing out that the measurement being cited was meaningless. Do
you agree with me that it is meaningless or not? Or are you going to change
the subject again?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

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On Wed, 11 Aug 2004 03:24:36 -0400, "Arny Krueger" <arnyk@hotpop.com>
wrote:

>What's so sacred about listening in an uncontrolled manner? Isn't it true
>that uncontrolled listening got us into this sitatuion where Monte McGuire
>is ranting and raving about 0.003% distortion being "just below our
>threshold of perception", while his speakers still have 10% THD?

An "uncontrolled manner" is how we listen to music.

In order to so casually dismiss someone else's observations, you
should first show the relevance of your tests to those observations.
This has not been done.

Ranting and raving?

The map is not the world. To dismiss observations that conflict
with one's model is a Procrustean bed, and historically short
sighted.

Chris Hornbeck

 

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"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in message
news:k2bkh05qn10cts95iakj3s7gda8i721mhg@4ax.com
> On Wed, 11 Aug 2004 03:24:36 -0400, "Arny Krueger" <arnyk@hotpop.com>
> wrote:
>
>> What's so sacred about listening in an uncontrolled manner? Isn't it
>> true that uncontrolled listening got us into this sitatuion where
>> Monte McGuire is ranting and raving about 0.003% distortion being
>> "just below our threshold of perception", while his speakers still
>> have 10% THD?

> An "uncontrolled manner" is how we listen to music.

But this isn't about just listening to music for enjoyment. And, its not
about audio production. It's about evaluating critical tools. It's about
resolving a controversy in a reliable and fair way.

> In order to so casually dismiss someone else's observations, you
> should first show the relevance of your tests to those observations.

Been there done that.

> This has not been done.

Really? What are you looking for? I think that history shows that I've made
many contributions to the reliable audio testing *blood bank*. A few people
have even found them helpful. ;-)

> Ranting and raving?

Not at all. Calling 'em like they are.

> The map is not the world. To dismiss observations that conflict
> with one's model is a Procrustean bed, and historically short
> sighted.

What, another spirited defense of ureliable, poorly-structured listening
tests?

 

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In article <tKmdnZ5FkrWHV4TcRVn-rg@comcast.com>,
"Arny Krueger" <arnyk@hotpop.com> wrote:

> "Monte McGuire" <monte.mcguire@verizon.net> wrote in message
> news:monte.mcguire-6B2C4B.01194511082004@news.verizon.net
>
> > Again, what's the big savings?
>
> What's wrong with recognizing that we play that DAC with 0.00015% THD
> through speakers with 0.1 to 1.0 to 10% THD, depending on what frequency in
> the audio range you are talking about, and instead throwing our efforts into
> fixing that speaker with 10% THD?

For starters, I don't sell the output of my speakers. I use the output
of my speakers to influence the content of the audio signals that people
pay me to produce.

Secondly, why do you think my speakers are low resolution junk? They're
Quad ESL 63. They have pretty low distortion actually. No crossover
either. Have you ever heard or used them? The resolution is actually a
problem for a lot of people, as it influences how they hear the effects
used in a mix. I keep some computer speakers around to provide a
contrast, since most people tend to underuse effects when they're
presented at high resolution.

> What's so sacred about listening in an uncontrolled manner? Isn't it true
> that uncontrolled listening got us into this sitatuion where Monte McGuire
> is ranting and raving about 0.003% distortion being "just below our
> threshold of perception", while his speakers still have 10% THD?

I never claimed any of this, nor do my speakers have 10% distortion when
used in my studio. Why do you make these statements? What help is it
to you to distort my position? Does it make you feel good to cuddle up
to a bully troll while I'm trying to honestly talk about audio?


Monte McGuire
monte.mcguire@verizon.net

 

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On Wed, 11 Aug 2004 11:09:00 -0400, "Arny Krueger" <arnyk@hotpop.com>
wrote:

>> An "uncontrolled manner" is how we listen to music.
>
>But this isn't about just listening to music for enjoyment. And, its not
>about audio production. It's about evaluating critical tools. It's about
>resolving a controversy in a reliable and fair way.

Certainly. I would only modify that to "reliable, fair and relevant".

>> This has not been done.
>
>Really? What are you looking for?

The unstated and unproved assumption of DBT is that our listening
mechanisms work the same way when in an "uncontrolled manner" as
when engaged in "testing".

Given the vast gulf of our ignorance about listening and about
our wetware in general, I think the assumption at least premature
and very likely wrong.

>What, another spirited defense of ureliable, poorly-structured listening
>tests?

An adult lifetime's experience may seem poorly structured and may
indeed prove unreliable, but these are not automatically true.

And a test regimen whose results conflict with a careful observer's
experience raises issues of relevance.

The map is not the world.

Chris Hornbeck

 

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"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in message
news:1tekh0htedp62tabkqk7dmdcbtni2rqs8q@4ax.com
> On Wed, 11 Aug 2004 11:09:00 -0400, "Arny Krueger" <arnyk@hotpop.com>
> wrote:

>>> An "uncontrolled manner" is how we listen to music.

>> But this isn't about just listening to music for enjoyment. And, its
>> not about audio production. It's about evaluating critical tools.
>> It's about resolving a controversy in a reliable and fair way.

> Certainly. I would only modify that to "reliable, fair and relevant".

The idea that a listening test becomes irrelevant simply because modest
attempts are made to resolve a few very obvious problems seems pretty darn
strange.

Some people say, "See I hear a difference, and that proves that the
guildersleeve affects the geframus"

I say: "But the levels are significantly mismatched, the timing is
significantly mismatched, the identity of the UUTs is clearly visible, and a
smart deaf 8-year old could duplicate or surpass your accuracy as a
listener."

>>> This has not been done.

>> Really? What are you looking for?

> The unstated and unproved assumption of DBT is that our listening
> mechanisms work the same way when in an "uncontrolled manner" as
> when engaged in "testing".

I'm willing to stipulate that critical listening and listening for pleasure
are very different things. But, I'll resist any attempt to find some kind of
special boogey man that is relevant only to DBTs.

> Given the vast gulf of our ignorance about listening and about
> our wetware in general, I think the assumption at least premature
> and very likely wrong.

As long as people quit trying to load DBTs up with a lot of baggage that
affects any attempt at critical listening, there's no problem.

>> What, another spirited defense of unreliable, poorly-structured
>> listening tests?

> An adult lifetime's experience may seem poorly structured and may
> indeed prove unreliable, but these are not automatically true.

Basic common-sense requirements aren't falsified by dismissal or vague
claims about some unique, mysterious, asymmetry.

> And a test regimen whose results conflict with a careful observer's
> experience raises issues of relevance.

There seems to be two kinds of people in the world. Some see their illusions
crushed in a DBT and say, "Oh my gosh that was an illusion", and then they
move on. Other people seem to want to fight their problem to the death,
inventing and/or invoking all kinds of weird science along the way.

> The map is not the world.

That's obvious. So obvious that it raises issues that really don't need to
be raised at this time.

 

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"Monte McGuire" <monte.mcguire@verizon.net> wrote in message
news:monte.mcguire-6B2C4B.01194511082004@news.verizon.net...
> Why not have a little extra performance in your system? What would be
> so bad about that? It might actually sound better in some situation
> that you didn't have the time or foresight to construct a DBT to
> specifically screen against. I'm honestly trying to find out exactly
> what the savings are of having optimally bad performing gear, stuff that
> has weaknesses, but which are just below our threshold of perception.
> Can you assure that all possible combinations of such gear still have
> shortcomings that are still inaudible? Again, what's the big savings?

That one is easy, MONEY!

Some people like to spend as much money as they possibly can in an attempt
to convince themselves that is the only road to satisfaction.
Others try to evaluate performance Vs cost, and come to a suitable
compromise within their aims and budget.

Since you can afford the former, good luck to you. Many others can't.

TonyP.

 

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"Monte McGuire".
> "Phil Allison"
> >
> > > I usually use a measurement bandwidth for THD+N that allows for
> > > harmonics above 20KHz, since nonlinearities up there could also
manifest
> > > themselves as IMD, not just as harmonics that are inaudible. So,
that's
> > > why I suggested that your .003% number might be mostly noise.
> >
> > ** Do a test - see that it is not.
>
> OK, so your TL07x produces a lot more distortion when handling very
> simple pure tones of low frequency than other more modern amps produce.
> Great. We agree now; wasn't that my original contention?


** It was one of them - but not the one I disputed.

Better go back and re- read the thread.


>
> > > But, if .003% is specified with a tight bandwidth, then maybe it
really
> > > is all distortion and the TL072 really does make hash out of signals
> > > like I originally proposed.
> >
> >
> > ** Where did you get the ridiculous idea that anyone can hear 0.003%
THD
> > of any signal ????
>
>
> I don't particularly care about that _specifically_, but I do know that
> unless a device makes less distortion than another device, it cannot be
> considered cleaner than the other device. In other words, even though
> we may not be able to hear the errors that were directly measured, there
> may be other errors of a much larger magnitude (and are thus audible)
> that are generated with real world signals that arise from the same
> mechanisms that created the errors observed when handling the test
> signals.


** More audiophool mantras .........

" I think it might exist - ergo it does.... "


>
> Sure, the .0000whatever percent distortion handling a pure tone may not
> be audible. What happens with real music and complex sounds?


** Nothing unexpected.


> You cannot honestly say,


** No point in answering your questions if you intend to answer them all for
me.


>
> Why not have a little extra performance in your system?


** Fine with me.

But it is not correct to say to others that it will sound better.



> It might actually sound better in some situation
> that you didn't have the time or foresight to construct a DBT to
> specifically screen against.


** Another audiophool mantra - the paranoid mantra.


> honestly trying to find out exactly
> what the savings are of having optimally bad performing gear, stuff that
> has weaknesses, but which are just below our threshold of perception.


** Since when is 0.003% THD @ 10 kHz and 5 volts rms into 3 kohms load just
below perception ?




............. Phil

 

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Archived from groups: rec.audio.pro (More info?)

In article <2ntrmdF4fcvkU1@uni-berlin.de>,
"Phil Allison" <philallison@tpg.com.au> wrote:

> "Monte McGuire".
>
> > honestly trying to find out exactly
> > what the savings are of having optimally bad performing gear, stuff that
> > has weaknesses, but which are just below our threshold of perception.
>
>
> ** Since when is 0.003% THD @ 10 kHz and 5 volts rms into 3 kohms load just
> below perception ?

I didn't claim that. You claim that it's below the threshold of
perception. I claim that a device exhibiting such performance in a
THD+N test might not sound completely transparent given all possible
musical signals.

The reason I introduced the concept of "optimally bad performing gear"
is that if you use something like DBT to qualify each and every piece of
gear, you don't know whether the performance is just barely
satisfactory, or if it's good enough to remain inaudible with several
such devices chained together. You can't know unless you test each and
every combination explicitly.

For the work I do, I prefer to have a signal chain that is as good as
possible. I make recordings through this chain, and the end of my
signal path is the beginning of the listener's path. I'm not concerned
with the cost so much. It's cheaper for me to use a $3 op amp rather
than a $.50 op amp if it'll possibly give me better results. Not that
it's only about money either; oddly enough, certain kinds of $.50 op
amps work better than much more expensive op amps, and I choose those in
those situations.

What I can't do is run every recording session twice (or five times or
whatever) in order to construct rigorous listening tests. I only have
one shot at it, so I try to find out what gear has the best chance of
working well and then use that. I suspect that people who do a lot of
testing really can't get much real work done. If so, then I'd love to
know how, but the only other option is to test things that are theorized
to be relevant and make extrapolations from there to the actual work.
How is that any more rigorous than using test equipment? It's still a
leap, since it never refers to a completely realistic situation.


Monte McGuire
monte.mcguire@verizon.net