tweaks and proof

[Guest]

Archived from groups: rec.audio.high-end (More info?)

Sean Fulop <sfulop@uchicago.edu> wrote:
> And I repeat, we cannot be sure that everything can be measured. No
> researcher in sound or signal processing could be taken seriously if he
> said otherwise, given the advances in measuring properties of the signal
> that are made each week and reported in the journals. Now, on the other
> hand, if two outputs produce exactly the same signal down to the 96 kHz
> sampled bit, then they are indeed "the same". Comparing two digitized
> signals can be done simply, just look at their matrices and see whether
> the cells all have the same numbers.

> But I don't think this is what people mean when they say there is "no
> measurable difference," they are usually talking about staring at some
> graph or chart or something that has been computed as a property of the
> signals. And there is good reason to try this, since the bit-identity of
> two signal waveforms is really not at all correlated with two signals
> seeming to "sound the same." Drastically different signals can be
> easily made which sound the same, because of the variety of effects to
> which the ear is not sensitive.

Seems to me you have it backwards.

Two bit-identical tracks will very likely sound the same.
Tus bit-identity is correlated to aural identity; more
properly, it is *sufficient* for aural identity.

That does not mean that *sounding the same* correlates as well to
bit-identity. The relationship is not reciprocal, for the
reason you state. Aural identity is not sufficient reason
to conclude bit-identity.

--

-S.
Why don't you just admit that you hate music and leave people alone. --
spiffy <thatsright@excite.co>

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

Codifus codifus@optonline.net wrote:

>Nousaine wrote:
>
>> tchelvam@hotmail.com (TChelvam) wrote:
>>
>>
>>>Steven Sullivan <ssully@panix.com> wrote in message
>>>news:<gBMzc.40266$eu.31721@attbi_s02>...
>>>
>>>
>>>>What's to prevent someone from claiming, 'you haven't measured the *right
>>>
>>>thing*'?
>>>
>>>>Along with the ever-popular 'not everything can be measured'?
>>>
>>>Like what they said in 1994 or 1993 issue of The Absolute Sound.
>>>It goes something like this " ...the engineers must be laughing when
>>>one magazine claimed that they managed to do meaningful jitter
>>>measurement.".
>>>
>>>I guess they must be laughing now at their ignorance, then.
>>>
>>>Probably, prior to 1985, we do not know what a jitter was.
>>
>>
>> Actually jitter was a known and solved problem in telecommunications 20
>years
>> prior to that. The American public first used digital audio as early as
>1962
>> when Westren Electric installed the first digital carrier systems in the
>long
>> distance network in Illinois.
>>
>> As a former Bell Labs scientist explained to me about 1986; jitter can be
>a
>> performance issue when you have a call that is placed from New Jersey and
>> finally connected in Los Angeles after several alternate possible
>route-ings
>> and multiple analog to digital and reverse conversions but it isn't an
>issue
>> between your cd player and dac inboard or otherwise.
>>
>But then, that would depend on the quality of the measurment. In phone
>conversation, we aren't looking for audiophile quality, so any jitter
>they find on the phone must be extreme. The jitter in audio is probably
>high enough to be bothersome to those "golden ears" but more than
>acceptable to phone conversations.
>
>CD

Even if that were to be true the original claim was

>>>Probably, prior to 1985, we do not know what a jitter was.

Which is patently untrue. Also note that Mr Pierce made reference to a bbc
paper published in 1974.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

s888wheel@aol.com (S888Wheel) wrote:

From: mikescarpitti@yahoo.com (Michael Scarpitti)
>>Date: 6/16/2004 3:32 PM Pacific Standard Time
>>Message-id: <caqhpg0319v@news2.newsguy.com>
>>
>>s888wheel@aol.com (S888Wheel) wrote in message
>>news:<cao1tr0h93@news4.newsguy.com>...
>>
>>> I think one could start by comparing actual signals. If a given tweak
>makes
>>> absolutely no measurable difference in the signal then it can't possibly
>>make a
>>> difference in the sound.
>>
>>Not supportable. What evidence do you have that 'everything audible'
>>is the same set as 'everything measurable'?
>>
>>
>>
>>
>>
>>
>
>If one is hearing a difference then there is a measurable difference. Your
>ears
>are in effect measuring it. There are microphones and measuring instruments
>that are far more sensitive than our ear/brian. If the ear/brain can pick up
>a
>difference so can the right mic/bench equipment, it is measurable.

I'd generally agree.But, in your opinion, what is the measurable mechanism that
produces audible differences in amp/wire sound?

 

[chung]

Archived from groups: rec.audio.high-end (More info?)

S888Wheel wrote:

>
>>And, too, a measurable difference is not necessarily audible.
>
>
> Never said it was. However if there is no measurable differences between two
> signals then there is nothing to discuss. They will make the same sound with
> the same associated equipment.
>

The problem, of course, is that usually there is a measureable
difference between two components, since our measuring instruments are
so sensitive. Take two cables of the same make, one 3 ft long and one
3.1 ft long. There is a measureable difference. Heck, the lengths are
clearly different. And we can certainly resolve the 0.1 nanosecond or so
in delay. It would take an extreme subjectivist, however, to claim that
there is a sonic difference between those two.

The crux of the problem is in the disagreement on what differences are
detectible via listening only. Past research indicates that level
differences of less than 0.3 dB over the audio band are not detectible
by listeners. Let's be generous and tighten that to 0.2 dB. If we would
agree that this is the threshold of audibility, then we can prove fairly
easily that 99% of the cables and interconnects do sound the same.

 

[lasse]

Archived from groups: rec.audio.high-end (More info?)

"Michael McKelvy" <deskst49@peoplepc.com> wrote in message news:<kn4Ac.45987$eu.38549@attbi_s02>...
>
> We can't? Why not?
> Isn't the job of any audio component supposed to be that it reproduce the
> signal being fed to it without any audible distortion and with flat
> Frequency response? That is the definition of High Fidelity that I use.

Well, knowing what is perfect is way different than ranking two
imperfect measurements. Consider that there is two speakers with
almost linear FR. However, other has slight bump in 3k region and
other has similar bump in 5k region. How can we tell which is
better without listening?

Lasse Ukkonen

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

nousaine@aol.com (Nousaine) wrote in message news:<car1t502peh@news3.newsguy.com>...
> Codifus codifus@optonline.net wrote:

>> >But then, that would depend on the quality of the measurment. In
phone
> >conversation, we aren't looking for audiophile quality, so any jitter
> >they find on the phone must be extreme. The jitter in audio is probably
> >high enough to be bothersome to those "golden ears" but more than
> >acceptable to phone conversations.
> >
> >CD
>
> Even if that were to be true the original claim was
>
> >>>Probably, prior to 1985, we do not know what a jitter was.
>
> Which is patently untrue. Also note that Mr Pierce made reference to a bbc
> paper published in 1974.

Well, when I said "we' I was refering to the digital audio world in
particular to CD sound reproduction. When CD player manufacturer and
the audio engineer paid significant attention to address jitter? 1974,
1985 or early 1990?

 

[ban]

Archived from groups: rec.audio.high-end (More info?)

Buster Mudd wrote:

Before & After "tweaks" would be to
> measure the acoustic output of the complete sound system in the room.
> It does no good (other than to assure some smug self-congratulatory
> backpatting amongst the naysayers) to measure the electrical signal at
> the output of a $200 interconnect cable & show that it is identical to
> the electrical output of a $4 interconnect cable; the tweakophile who
> claims he heard a difference heard it connected to the rest of his
> audio system in his listening room through his ears, *not* through
> some direct electrical connection to the cable. Perhaps that $200
> cable interacts bizarrely with the rest of his components, causing
> them to perform differently? If so, one would be hard pressed to argue
> that difference is not a measurable difference. Time Domain
> Spectrometry and FFT can map some fairly refined acoustic phenomena,
> so why not measure the sum total net difference in acoustic output of
> a sound system, both Before & After the application of a "tweak" &
> compare the results?

Buster, you are wrong here, if there is any measurable difference at the
output of the system, it will already show up at the output of the
interconnect. The whole system works at exactly the same operating point and
the single components will multiply their transmission functions. It is like
6x5= 5x6= identical. So no matter where you tweak, the difference will be
there in the chain after the tweaked component and will go on being there
exactly alike (as long as the system is linear) down the chain until the
output.
If you have applied several different tweaks, the final output will be
exactly the product of each individual one and will be measurable after each
changed component.
Your argumentation is not valid, it is governed by your belief and utterly
unscientific.

--
ciao Ban
Bordighera, Italy

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

"Sean Fulop" <sfulop@uchicago.edu> wrote in message
news:caqhu302fh@news2.newsguy.com...
> Steven Sullivan wrote:
> > S888Wheel <s888wheel@aol.com> wrote:
> >
> >>>From: "Rich.Andrews" bvzxrpl@swissinfo.org
> >>>Date: 6/15/2004 3:52 PM Pacific Standard Time
> >>>Message-id: <canuit01vmq@news2.newsguy.com>
> >>>
> >>>With all of the discussion regarding "tweaks" and "mods" that has been
> >>>prevalent, I was wondering not if any of them had any merit, or hold
even
> >>>then slightest chance of making a difference, but whether or not one
could
> >>>devise a quantifiable test to prove the claims made. I think it is up
to
> >>>the person making the claims to prove them.
> >>>
> >>>In the medical field there is anecdote and there is proof. Without
proof,
> >>>an anecdote is just that, a nice story. An anecdote could also be an
> >>>indicator that some effect is happening, but the anecdote by itself
> >>>substantiates or proves nothing.
> >>>
> >>>For example, how can one devise a test to prove that XYZ product not
just
> >>>sounds but also measures "significantly" different than the $0.49
variety
> >>>available at Walmart? If we are able to view and manipulate single
atoms,
> >>>there must be a way to measure and quantify and therefore qualify an
> >>>effect claimed.
> >>>
> >>>It is as if we are in the early days of Hi-Fi placing speakers in
cabinets
> >>>of various sizes until we find something that sounds good. We are
trying
> >>>all manner of substances without a clue as to what is going on.
> >>>
> >>>As near as I can tell, those making claims of speaker cables,
> >>>interconnects, etc are just guessing at what is going on. They don't
know
> >>>and even if they did, they can't prove it with measurements and tests
> >>>using laboratory equipment. There are some theories floating around,
but
> >>>no one has proposed any experiments to prove these theories. I believe
> >>>that if we fully understand a mechanism, then we are able to produce a
> >>>better product than all of the guesswork done previously.
> >>>
> >>>This begs the question of how would one go about proving these
> >>>unsubstaniated claims.
> >>>
> >>>r
> >>>
> >>>
> >>>--
> >>>Nothing beats the bandwidth of a station wagon filled with DLT tapes.
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >
> >
> >>I think one could start by comparing actual signals. If a given tweak
makes
> >>absolutely no measurable difference in the signal then it can't possibly
make a
> >>difference in the sound.
> >
> >
> > What's to prevent someone from claiming, 'you haven't measured the
*right thing*'?
> > Along with the ever-popular 'not everything can be measured'?
> >
> > And, too, a measurable difference is not necessarily audible.
> >
>
> And I repeat, we cannot be sure that everything can be measured.

Then you can't be sure it can't be either. Everything I've seen on the
subject says that we have the ability to measure everything hearable.
Unless youhave some proof that the right things or everything isn't being
measured, you're just making a blank assertion.

No
> researcher in sound or signal processing could be taken seriously if he
> said otherwise, given the advances in measuring properties of the signal
> that are made each week and reported in the journals.

It's true we can measure things we can't hear, so what?

Now, on the other
> hand, if two outputs produce exactly the same signal down to the 96 kHz
> sampled bit, then they are indeed "the same". Comparing two digitized
> signals can be done simply, just look at their matrices and see whether
> the cells all have the same numbers.
>
> But I don't think this is what people mean when they say there is "no
> measurable difference," they are usually talking about staring at some
> graph or chart or something that has been computed as a property of the
> signals.

If there is no measurable difference there is no audible difference.

And there is good reason to try this, since the bit-identity of
> two signal waveforms is really not at all correlated with two signals
> seeming to "sound the same." Drastically different signals can be
> easily made which sound the same, because of the variety of effects to
> which the ear is not sensitive.
>
Then it doesn't matter, if they sound the same they are the same to the
listener.

> But, alas, once you break away from simply comparing two signals (i.e.
> their matrices) to see whether they are in fact the same (not unlike
> using Unix 'grep' to compare two text files), you can no longer be
> certain of your assertions to the effect that your failure to measure
> any difference represents everyone's inability to hear any difference.
>
Which is why tools like ABX are valuable.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

From: chung chunglau@covad.net
>Date: 6/17/2004 3:29 PM Pacific Standard Time
>Message-id: <cat60g0dm7@news2.newsguy.com>
>
>S888Wheel wrote:
>
>>
>>>And, too, a measurable difference is not necessarily audible.
>>
>>
>> Never said it was. However if there is no measurable differences between
>two
>> signals then there is nothing to discuss. They will make the same sound
>with
>> the same associated equipment.
>>
>
>The problem, of course, is that usually there is a measureable
>difference between two components, since our measuring instruments are
>so sensitive.

It is not a problem for the instances in which there is no measurable
differrence. One saves themselves the rigor of doing any further testing. So it
still makes sense to start there.

Take two cables of the same make, one 3 ft long and one
>3.1 ft long. There is a measureable difference. Heck, the lengths are
>clearly different. And we can certainly resolve the 0.1 nanosecond or so
>in delay.

A delay is not inherently a difference in the signal. Heck you can measure
differnt components days apart and there is a substantial delay but the signal
is what it is each time.

It would take an extreme subjectivist, however, to claim that
>there is a sonic difference between those two.

It would take a mistake in one's impression to say there is an audible
difference if the only measurable difference is a nano second delay. Even if
the comparisons are supposed to be syncronized. If they are not syncronized
there is no measurable difference is there since such delays are irrelevent to
the content of the signal.

>
>The crux of the problem is in the disagreement on what differences are
>detectible via listening only. Past research indicates that level
>differences of less than 0.3 dB over the audio band are not detectible
>by listeners. Let's be generous and tighten that to 0.2 dB. If we would
>agree that this is the threshold of audibility, then we can prove fairly
>easily that 99% of the cables and interconnects do sound the same.
>
>
>
>
>
>
I said never said measurable differences were the end, only the start. If there
is no measurable difference it is the start and end. In some cases some time
and effort can be saved.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

Ban,
You may be overlooking the effect of the acoustic output on the system
mechanically and the effect of room acoustics. There are some tweeks
such as a form of isolation that will have both audible and measurable
results. Obviously not all components would be effected the same way
and thus a given form of isolation may only work well on one portion
of the system, where it would not have an audible effect on another.
You do have to look at the system as a whole to get the acoustic
output, plus the loop feedback and room response. I see where you are
going with this, but it does limit the measurements to specific
components. A good example of a situation where a tweek could not be
measured at a cable termination would be an acoustic wall treatment,
which could be considered a tweek as it would also effect the sound,
but it could not be measured anywhere but in the room of course. It
would just be easier to measure what you hear in the room at that
point to compare it to what you are hearing for a 1:1. I like the 1:1
scenario best as it allows you to hear and read the results
simultaneously and you can be confident that you are actually
measuring what you are hearing (or not hearing)... Using a mic in
the room, you could verify graphically what was being done with a
tweek (a laptop would be easiest to read and have at the listening
position). It would also provide rather convincing evidence of the
effectiveness of a particular tweek as the original poster had
pondered. It would still not provide a "better or worse" evaluation
from a subjective standpoint, just a result. Hey, some people love
their tube amps and peculiar speakers...
-Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250

"Ban" <bansuri@web.de> wrote in message
news:cat6a40duq@news2.newsguy.com...
> Buster Mudd wrote:
>
> Before & After "tweaks" would be to
> > measure the acoustic output of the complete sound system in the
room.
> > It does no good (other than to assure some smug
self-congratulatory
> > backpatting amongst the naysayers) to measure the electrical
signal at
> > the output of a $200 interconnect cable & show that it is
identical to
> > the electrical output of a $4 interconnect cable; the tweakophile
who
> > claims he heard a difference heard it connected to the rest of his
> > audio system in his listening room through his ears, *not* through
> > some direct electrical connection to the cable. Perhaps that $200
> > cable interacts bizarrely with the rest of his components, causing
> > them to perform differently? If so, one would be hard pressed to
argue
> > that difference is not a measurable difference. Time Domain
> > Spectrometry and FFT can map some fairly refined acoustic
phenomena,
> > so why not measure the sum total net difference in acoustic output
of
> > a sound system, both Before & After the application of a "tweak" &
> > compare the results?
>
> Buster, you are wrong here, if there is any measurable difference at
the
> output of the system, it will already show up at the output of the
> interconnect. The whole system works at exactly the same operating
point and
> the single components will multiply their transmission functions. It
is like
> 6x5= 5x6= identical. So no matter where you tweak, the difference
will be
> there in the chain after the tweaked component and will go on being
there
> exactly alike (as long as the system is linear) down the chain until
the
> output.
> If you have applied several different tweaks, the final output will
be
> exactly the product of each individual one and will be measurable
after each
> changed component.
> Your argumentation is not valid, it is governed by your belief and
utterly
> unscientific.
>
> --
> ciao Ban
> Bordighera, Italy

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

Actually, that is exactly what I was saying about the acoustic output
of the system in the room and including the room acoustics, but I
would not go as far as to call cables a tweek - a necessity perhaps.
-Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250

"Buster Mudd" <mr_furious@mail.com> wrote in message
news:caqheg02qp9@news2.newsguy.com...
> Uptown Audio <uptownaudio@rev.net> wrote in message
news:<eEOzc.47487$0y.2739@attbi_s03>...
> > That is not true of acoustics unless the signal being measured is
the
> > acoustic output (room + signal). In other words, anything that is
done
> > to effect the acoustics (or mechanical isolation from acoustic
> > feedback in the case of equipment) could be considered a tweek if
it
> > were not part of the original equipment but could also not be
measured
> > as part of the electrical signal only.
>
> Ironically I was thinking along similar lines, except taking it
> farther to say that the only conceivable way to measure alleged
> audible differences between Before & After "tweaks" would be to
> measure the acoustic output of the complete sound system in the
room.
> It does no good (other than to assure some smug self-congratulatory
> backpatting amongst the naysayers) to measure the electrical signal
at
> the output of a $200 interconnect cable & show that it is identical
to
> the electrical output of a $4 interconnect cable; the tweakophile
who
> claims he heard a difference heard it connected to the rest of his
> audio system in his listening room through his ears, *not* through
> some direct electrical connection to the cable. Perhaps that $200
> cable interacts bizarrely with the rest of his components, causing
> them to perform differently? If so, one would be hard pressed to
argue
> that difference is not a measurable difference. Time Domain
> Spectrometry and FFT can map some fairly refined acoustic phenomena,
> so why not measure the sum total net difference in acoustic output
of
> a sound system, both Before & After the application of a "tweak" &
> compare the results?

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

tchelvam@hotmail.com (TChelvam) wrote:



>nousaine@aol.com (Nousaine) wrote in message
>news:<car1t502peh@news3.newsguy.com>...
>> Codifus codifus@optonline.net wrote:
>
>>> >But then, that would depend on the quality of the measurment. In
>phone
>> >conversation, we aren't looking for audiophile quality, so any jitter
>> >they find on the phone must be extreme. The jitter in audio is probably
>> >high enough to be bothersome to those "golden ears" but more than
>> >acceptable to phone conversations.
>> >
>> >CD
>>
>> Even if that were to be true the original claim was
>>
>> >>>Probably, prior to 1985, we do not know what a jitter was.
>>
>> Which is patently untrue. Also note that Mr Pierce made reference to a bbc
>> paper published in 1974.
>
>Well, when I said "we' I was refering to the digital audio world in
>particular to CD sound reproduction. When CD player manufacturer and
>the audio engineer paid significant attention to address jitter? 1974,
>1985 or early 1990?

Well they didn't have to; because jitter is not now, nor has it ever been, a
"problem" with digital recording and playback.

But back to the original posting----- there was never a "time" when jitter was
not known or hadn't addressed in an engineering sense.

 

[chung]

Archived from groups: rec.audio.high-end (More info?)

S888Wheel wrote:
> From: chung chunglau@covad.net
>>Date: 6/17/2004 3:29 PM Pacific Standard Time
>>Message-id: <cat60g0dm7@news2.newsguy.com>
>>
>>S888Wheel wrote:
>>
>>>
>>>>And, too, a measurable difference is not necessarily audible.
>>>
>>>
>>> Never said it was. However if there is no measurable differences between
>>two
>>> signals then there is nothing to discuss. They will make the same sound
>>with
>>> the same associated equipment.
>>>
>>
>>The problem, of course, is that usually there is a measureable
>>difference between two components, since our measuring instruments are
>>so sensitive.
>
> It is not a problem for the instances in which there is no measurable
> differrence.

My point is that there are very few instances where there is no
measureable difference, because of the sensitivity of our test instruments.

Care to provide examples where differences are not measureable?

> One saves themselves the rigor of doing any further testing. So it
> still makes sense to start there.

Only in principle. Not in practice.

>
> Take two cables of the same make, one 3 ft long and one
>>3.1 ft long. There is a measureable difference. Heck, the lengths are
>>clearly different. And we can certainly resolve the 0.1 nanosecond or so
>>in delay.
>
> A delay is not inherently a difference in the signal.

Why not? What about a difference in phase shift? What about the 0.001dB
in level due to the difference in resistance? How about the differences
in resistance, capacitance and inductance?

> Heck you can measure
> differnt components days apart and there is a substantial delay but the signal
> is what it is each time.

No, the analogy is incorrect. One could measure those two cables at any
time, at any place, with any set of accurate instruments and get the
same difference in measurements. These differences are repeatable, and
objective.

>
> It would take an extreme subjectivist, however, to claim that
>>there is a sonic difference between those two.
>
> It would take a mistake in one's impression to say there is an audible
> difference if the only measurable difference is a nano second delay.

There, you are beginning to make the point for me. You are providing a
juegment call that a nanosec. delay does not cause an *audible*
difference. Just like I may say that a difference in level of 0.1 dB is
not an audible difference, but would everyone agree?

Of course, I agree that that delay is not audible, but nonetheless there
is a *measureable* difference.

The difficulty is in agreeing what is an inaudible but measureable
difference.

Another example. Two preamps of the same make, model and specs. One has
an output impedance of 200 ohms. The other 202 ohms. Clearly there is a
measureable difference. Is it audible?


> Even if
> the comparisons are supposed to be syncronized. If they are not syncronized
> there is no measurable difference is there since such delays are irrelevent to
> the content of the signal.

You are making a judgment call on what constitiutes an audible
difference. By the way, that is the kind of calls that a lot of the more
scientific-minded have tried to make (like one can't tell differences in
level finer than 0.1dB, or one can't hear above 20 KHz), and a lot of
so-called golden-ear audiphiles do not agree with.

>
>>
>>The crux of the problem is in the disagreement on what differences are
>>detectible via listening only. Past research indicates that level
>>differences of less than 0.3 dB over the audio band are not detectible
>>by listeners. Let's be generous and tighten that to 0.2 dB. If we would
>>agree that this is the threshold of audibility, then we can prove fairly
>>easily that 99% of the cables and interconnects do sound the same.
>>
>>
>>
>>
>>
>>
> I said never said measurable differences were the end, only the start. If there
> is no measurable difference it is the start and end. In some cases some time
> and effort can be saved.
>

Very, very few cases. It's better to go straight to controlled listening
tests, IMO.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

Uptown Audio uptownaudio@rev.net wrote:

>Ban,
>You may be overlooking the effect of the acoustic output on the system
>mechanically and the effect of room acoustics. There are some tweeks
>such as a form of isolation that will have both audible and measurable
>results. Obviously not all components would be effected the same way
>and thus a given form of isolation may only work well on one portion
>of the system, where it would not have an audible effect on another.
>You do have to look at the system as a whole to get the acoustic
>output, plus the loop feedback and room response. I see where you are
>going with this, but it does limit the measurements to specific
>components. A good example of a situation where a tweek could not be
>measured at a cable termination would be an acoustic wall treatment,
>which could be considered a tweek as it would also effect the sound,
>but it could not be measured anywhere but in the room of course. It
>would just be easier to measure what you hear in the room at that
>point to compare it to what you are hearing for a 1:1. I like the 1:1
>scenario best as it allows you to hear and read the results
>simultaneously and you can be confident that you are actually
>measuring what you are hearing (or not hearing)... Using a mic in
>the room, you could verify graphically what was being done with a
>tweek (a laptop would be easiest to read and have at the listening
>position). It would also provide rather convincing evidence of the
>effectiveness of a particular tweek as the original poster had
>pondered. It would still not provide a "better or worse" evaluation
>from a subjective standpoint, just a result. Hey, some people love
>their tube amps and peculiar speakers...
>-Bill
>www.uptownaudio.com
>Roanoke VA
>(540) 343-1250

I'm all for acoustic measurements but to measure the effect of a cable, for
example, there is no need to do so. If the signal reaching the speaker
terminals hasn't changed then the output of the speaker cannot have changed.

Occasionally I have also seen some pretty grim errors people have made in
interpreting acoustical measurements in a room. For example it's pretty easy to
break-down the test set-up (or to accidentally move the microphone or to fail
to record levels) and then not duplicate the measurement procedure precisely
and then draw bad conclusions. For example moving the microphone an inch can
"change" a single measurement trace (so can your furnace turning on; traffic,
etc) and make interpretation difficult.

IMO if one can measure the item being tested at its output the data is as good
as it can be. Of course, room acoustics and loudspeakers have to be evaluated
with acoustical measurements but upstream components need not necessarily be
done that way.


>"Ban" <bansuri@web.de> wrote in message
>news:cat6a40duq@news2.newsguy.com...
>> Buster Mudd wrote:
>>
>> Before & After "tweaks" would be to
>> > measure the acoustic output of the complete sound system in the
>room.
>> > It does no good (other than to assure some smug
>self-congratulatory
>> > backpatting amongst the naysayers) to measure the electrical
>signal at
>> > the output of a $200 interconnect cable & show that it is
>identical to
>> > the electrical output of a $4 interconnect cable; the tweakophile
>who
>> > claims he heard a difference heard it connected to the rest of his
>> > audio system in his listening room through his ears, *not* through
>> > some direct electrical connection to the cable. Perhaps that $200
>> > cable interacts bizarrely with the rest of his components, causing
>> > them to perform differently? If so, one would be hard pressed to
>argue
>> > that difference is not a measurable difference. Time Domain
>> > Spectrometry and FFT can map some fairly refined acoustic
>phenomena,
>> > so why not measure the sum total net difference in acoustic output
>of
>> > a sound system, both Before & After the application of a "tweak" &
>> > compare the results?
>>
>> Buster, you are wrong here, if there is any measurable difference at
>the
>> output of the system, it will already show up at the output of the
>> interconnect. The whole system works at exactly the same operating
>point and
>> the single components will multiply their transmission functions. It
>is like
>> 6x5= 5x6= identical. So no matter where you tweak, the difference
>will be
>> there in the chain after the tweaked component and will go on being
>there
>> exactly alike (as long as the system is linear) down the chain until
>the
>> output.
>> If you have applied several different tweaks, the final output will
>be
>> exactly the product of each individual one and will be measurable
>after each
>> changed component.
>> Your argumentation is not valid, it is governed by your belief and
>utterly
>> unscientific.
>>
>> --
>> ciao Ban
>> Bordighera, Italy
>
>
>
>
>
>
>

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

chung <chunglau@covad.net> wrote:
> S888Wheel wrote:
> > From: chung chunglau@covad.net
> >>Date: 6/17/2004 3:29 PM Pacific Standard Time
> >>Message-id: <cat60g0dm7@news2.newsguy.com>
> >>
> >>S888Wheel wrote:
> >>
> >>>
> >>>>And, too, a measurable difference is not necessarily audible.
> >>>
> >>>
> >>> Never said it was. However if there is no measurable differences between
> >>two
> >>> signals then there is nothing to discuss. They will make the same sound
> >>with
> >>> the same associated equipment.
> >>>
> >>
> >>The problem, of course, is that usually there is a measureable
> >>difference between two components, since our measuring instruments are
> >>so sensitive.
> >
> > It is not a problem for the instances in which there is no measurable
> > differrence.

> My point is that there are very few instances where there is no
> measureable difference, because of the sensitivity of our test instruments.

> Care to provide examples where differences are not measureable?

I would offer as an example bit-identity of two .wav files....which
has not prevented listeners from claiming that they still sound different.

In fact, what has happened in that case is lots of time spent trying
to find a *differnt* measurement to validate the supposed difference (with
'jitter' usually named, but AFAIK never proved to be, the culprit).


--

-S.
Why don't you just admit that you hate music and leave people alone. --
spiffy <thatsright@excite.co>

 

[chung]

Archived from groups: rec.audio.high-end (More info?)

Steven Sullivan wrote:
> chung <chunglau@covad.net> wrote:
>> S888Wheel wrote:
>> > From: chung chunglau@covad.net
>> >>Date: 6/17/2004 3:29 PM Pacific Standard Time
>> >>Message-id: <cat60g0dm7@news2.newsguy.com>
>> >>
>> >>S888Wheel wrote:
>> >>
>> >>>
>> >>>>And, too, a measurable difference is not necessarily audible.
>> >>>
>> >>>
>> >>> Never said it was. However if there is no measurable differences between
>> >>two
>> >>> signals then there is nothing to discuss. They will make the same sound
>> >>with
>> >>> the same associated equipment.
>> >>>
>> >>
>> >>The problem, of course, is that usually there is a measureable
>> >>difference between two components, since our measuring instruments are
>> >>so sensitive.
>> >
>> > It is not a problem for the instances in which there is no measurable
>> > differrence.
>
>> My point is that there are very few instances where there is no
>> measureable difference, because of the sensitivity of our test instruments.
>
>> Care to provide examples where differences are not measureable?
>
> I would offer as an example bit-identity of two .wav files....which
> has not prevented listeners from claiming that they still sound different.
>
> In fact, what has happened in that case is lots of time spent trying
> to find a *differnt* measurement to validate the supposed difference (with
> 'jitter' usually named, but AFAIK never proved to be, the culprit).
>
>

Yes, this is one of the few cases where you can measure no difference,
but that's between 2 CD's and probably not what audiophiles were
thinking of measuring. And there is speculation that bit-identical CD's
may still sound different due to jitter.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

On 6/18/04 9:42 PM, in article cb05lj04ne@news3.newsguy.com, "chung"
<chunglau@covad.net> wrote:

>> I would offer as an example bit-identity of two .wav files....which
>> has not prevented listeners from claiming that they still sound different.
>>
>> In fact, what has happened in that case is lots of time spent trying
>> to find a *differnt* measurement to validate the supposed difference (with
>> 'jitter' usually named, but AFAIK never proved to be, the culprit).
>>
>>
>
> Yes, this is one of the few cases where you can measure no difference,
> but that's between 2 CD's and probably not what audiophiles were
> thinking of measuring. And there is speculation that bit-identical CD's
> may still sound different due to jitter.

If there is one transport that produces high jitter and one that produces
low jitter - they will sound different. But it is measurable.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

From: chung chunglau@covad.net
>Date: 6/18/2004 10:48 AM Pacific Standard Time
>Message-id: <cav9t8020or@news3.newsguy.com>
>
>S888Wheel wrote:
>> From: chung chunglau@covad.net
>>>Date: 6/17/2004 3:29 PM Pacific Standard Time
>>>Message-id: <cat60g0dm7@news2.newsguy.com>
>>>
>>>S888Wheel wrote:
>>>
>>>>
>>>>>And, too, a measurable difference is not necessarily audible.
>>>>
>>>>
>>>> Never said it was. However if there is no measurable differences between
>>>two
>>>> signals then there is nothing to discuss. They will make the same sound
>>>with
>>>> the same associated equipment.
>>>>
>>>
>>>The problem, of course, is that usually there is a measureable
>>>difference between two components, since our measuring instruments are
>>>so sensitive.
>>
>> It is not a problem for the instances in which there is no measurable
>> differrence.
>
>My point is that there are very few instances where there is no
>measureable difference, because of the sensitivity of our test instruments.
>
>Care to provide examples where differences are not measureable?

Do you think green pens create a measurable difference in the output of a CD
player? Do you think anything Peter Belt ever invented created a measurable
difference in any audio signal?

>
>> One saves themselves the rigor of doing any further testing. So it
>> still makes sense to start there.
>
>Only in principle. Not in practice.

Fine. If you want to do elaborate DBTs for audible differences with and without
green pen and Peter Belt tweaks knock yourself out. I still think a simpler
solution is to measure the effect those products have on the signal to see if
there is any reason to go forward with any further investigation. Your time
your dime.

>
>>
>> Take two cables of the same make, one 3 ft long and one
>>>3.1 ft long. There is a measureable difference. Heck, the lengths are
>>>clearly different. And we can certainly resolve the 0.1 nanosecond or so
>>>in delay.
>>
>> A delay is not inherently a difference in the signal.
>
>Why not?

Explained further down in my post.

What about a difference in phase shift?

That's different.

What about the 0.001dB
>in level due to the difference in resistance?

That is different as well.

How about the differences
>in resistance, capacitance and inductance?

All different than a simple time delay.

>
>> Heck you can measure
>> differnt components days apart and there is a substantial delay but the
>signal
>> is what it is each time.
>
>No, the analogy is incorrect.

No it's not.

One could measure those two cables at any
>time, at any place, with any set of accurate instruments and get the
>same difference in measurements. These differences are repeatable, and
>objective.

That's fine, but if the only difference is the time delay than it is not a
difference in signal content.

>
>>
>> It would take an extreme subjectivist, however, to claim that
>>>there is a sonic difference between those two.
>>
>> It would take a mistake in one's impression to say there is an audible
>> difference if the only measurable difference is a nano second delay.
>
>There, you are beginning to make the point for me. You are providing a
>juegment call that a nanosec. delay does not cause an *audible*
>difference. Just like I may say that a difference in level of 0.1 dB is
>not an audible difference, but would everyone agree?

No. Everyone rarely agrees on anything in audio.

>
>Of course, I agree that that delay is not audible, but nonetheless there
>is a *measureable* difference.
>
>The difficulty is in agreeing what is an inaudible but measureable
>difference.

As I have said so many times now. I suggested that one *start* with checking
for measurable differences. If none exist then there is no need to go further.
I *never* said that any measurable difference is proof of an audible
difference. It is proof at best of a *possibility* of an audible difference. A
possibility that may need further investigation.

>
>Another example. Two preamps of the same make, model and specs. One has
>an output impedance of 200 ohms. The other 202 ohms. Clearly there is a
>measureable difference. Is it audible?
>
>
>> Even if
>> the comparisons are supposed to be syncronized. If they are not syncronized
>> there is no measurable difference is there since such delays are irrelevent
>to
>> the content of the signal.
>
>You are making a judgment call on what constitiutes an audible
>difference. By the way, that is the kind of calls that a lot of the more
>scientific-minded have tried to make (like one can't tell differences in
>level finer than 0.1dB, or one can't hear above 20 KHz), and a lot of
>so-called golden-ear audiphiles do not agree with.
>
>>
>>>
>>>The crux of the problem is in the disagreement on what differences are
>>>detectible via listening only. Past research indicates that level
>>>differences of less than 0.3 dB over the audio band are not detectible
>>>by listeners. Let's be generous and tighten that to 0.2 dB. If we would
>>>agree that this is the threshold of audibility, then we can prove fairly
>>>easily that 99% of the cables and interconnects do sound the same.
>>>
>>>
>>>
>>>
>>>
>>>
>> I said never said measurable differences were the end, only the start. If
>there
>> is no measurable difference it is the start and end. In some cases some
>time
>> and effort can be saved.
>>
>
>Very, very few cases. It's better to go straight to controlled listening
>tests, IMO.
>
>
>
>
>
>

Fine. Have fun with the Peter Belt tweaks. They'll waste about a week of your
time though.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

chung <chunglau@covad.net> wrote:
> Steven Sullivan wrote:
> > chung <chunglau@covad.net> wrote:
> >> S888Wheel wrote:
> >> > From: chung chunglau@covad.net
> >> >>Date: 6/17/2004 3:29 PM Pacific Standard Time
> >> >>Message-id: <cat60g0dm7@news2.newsguy.com>
> >> >>
> >> >>S888Wheel wrote:
> >> >>
> >> >>>
> >> >>>>And, too, a measurable difference is not necessarily audible.
> >> >>>
> >> >>>
> >> >>> Never said it was. However if there is no measurable differences between
> >> >>two
> >> >>> signals then there is nothing to discuss. They will make the same sound
> >> >>with
> >> >>> the same associated equipment.
> >> >>>
> >> >>
> >> >>The problem, of course, is that usually there is a measureable
> >> >>difference between two components, since our measuring instruments are
> >> >>so sensitive.
> >> >
> >> > It is not a problem for the instances in which there is no measurable
> >> > differrence.
> >
> >> My point is that there are very few instances where there is no
> >> measureable difference, because of the sensitivity of our test instruments.
> >
> >> Care to provide examples where differences are not measureable?
> >
> > I would offer as an example bit-identity of two .wav files....which
> > has not prevented listeners from claiming that they still sound different.
> >
> > In fact, what has happened in that case is lots of time spent trying
> > to find a *differnt* measurement to validate the supposed difference (with
> > 'jitter' usually named, but AFAIK never proved to be, the culprit).
> >
> >

> Yes, this is one of the few cases where you can measure no difference,
> but that's between 2 CD's and probably not what audiophiles were
> thinking of measuring.

Audiophiles have played a significant part in driving the whole 'bit identical
CDs sound different' goose chase.

As a result we have pseudoscientific websites such as:

http/www.altmann.haan.de/jitter/english/engc_navfr.html

where, after pages of technical discussion of jitter, interlaced with
qyestionable claims of audibility, we are presented with evidence....
from sighted comparison.


--

-S.
Why don't you just admit that you hate music and leave people alone. --
spiffy <thatsright@excite.co>

 

[ban]

Archived from groups: rec.audio.high-end (More info?)

Uptown Audio wrote:
> If what you say is true, then who is to say that because you could
> measure a difference that the difference is audible. It is much easier
> to just do both at the same time and at the same place. If it
> registers on the screen and you hear it, then you have your proof. Of
> course you have evidence of an effect with the measurement, but to
> really sell the idea of how effective it is, you need to hear it and
> to measure it in the room.

I agree

I don't think setting-up a system is all
> about collecting data, but in getting it to sound right. That may not
> necessarily make it measure as you would guess or hope. If all we had
> to do was measure at the source, there would be no need to listen to
> music, we could just all take your word that it sounds good? Boom
> boxes all around anyone?

A boom-box can be already identified by the impedance plot because it has a
high Q-factor in the resonance point and/or bad damping, which shows up and
is easily identifyable without even hearing it. But just this is the worst
example you chose to make your point. I would rather mention distortion
measurements, pulse response measurements or bumps in the frequency
response. Here even big differences might not be audible.
At the low end we can reliably differentiate between Q= 0.7 or 0.8, a very
slight change actually. Anyone correct me please if I'm wrong, couldn't find
data about this in the net.

Another problem with measuring in general and
> it really does not matter where, is having the appropriate gear and
> settings as well as knowing what to measure.

I encourage every audio enthusiast to start going this way, it incredibly
enhances the listening experience when you have a scientific understanding
which you gain by measuring. Room acoustics is a complicated but rewarding
subject to study and with todays possibilities of the net you do not need to
go to an expensive university but can do it at home (or work).
Actually I try with my 2cents contributions here to influence my fellow
music-lovers start experimenting themselves instead of believing doubtful
"misinformation" by mags. Better to spend the money you pay for high-end
mags to get a decent measurement system(clio-lite for example) and some good
books.


--
ciao Ban
Bordighera, Italy