[Dan Banquer]

Mr. Banquer, what equipment would I require to measure changes in noise, frequency response and distortion, and where would these measurements be taken?

Since no one in this discussion has done measurements, we can not conclude anything at this time.

There is no shortage of information on capacitor life time under varying conditions. There is also no shortage of info on tube lifetime under varying conditions. Please take the time to at least google some of these subjects.
One would need a RMS voltmeter, source generator, scope, and FFT/ Spectrum analyzer for the test equipment required.
             d.b.

[rajacat]

Why bother to audition any piece of audio equipment when you could just check out the published specs. and base your decision on them? What if two amps from different manufacturers have identical specs. but do not have identical perceived sound quality?

Raja

[Dan Banquer]

Please note that no major wire company (Belden, Carol, General Wire & Cable) or anyone in electrical engineering that I am aware of has found any changes in wire after 500 hours or whatever amount of time from "burn in".
Quite frankly, if there were changes, there would assorted graphs and charts from the companies mentioned above for engineers to account for in their designs.
                d.b.

[rajacat]

I don't think Mr. Banquer has conducted these tests. Perhaps nobody has.

[toobluvr]

Please note that no major wire company (Belden, Carol, General Wire & Cable) or anyone in electrical engineering that I am aware of has found any changes in wire after 500 hours or whatever amount of time from "burn in".
Quite frankly, if there were changes, there would assorted graphs and charts from the companies mentioned above for engineers to account for in their designs.
                d.b.

This proves nothing.
Maybe a physical change does indeed exist, but the device and methodology for proper measurement has not yet been developed.  Science is not perfect, and it is not complete.

I've spoken to many engineers and they pretty much all say the same thing.
It's all in the specs.  If the numbers are identical, two pieces will sound identical.

Let me ask you measurement types something.....
We have two caps by different manufacturers.
They test identical and have the same exact specs.
That is, they measure exactly the same in all regards.
Do you propose that they sound exactly the same?

If measurements tell the whole story, why upgrade and mod your gear?
Why replace one part for a "better" part with the same specs?
There is no sonic difference....right?
What's that you say..they do sound different?
Oh...but how is that possible...don't they measure the same?!   

Help me out here!  I'm just a simple non-scientist who neither distrusts nor disputes science, but realizes it is not always complete.             

[MaxCast]

Buy used, no worries   

[toobluvr]

We have two caps by different manufacturers.
They test identical and have the same exact specs.
That is, they measure exactly the same in all regards.
Do you propose that they sound exactly the same?

An excellent point. Why does a designer of audio electronics choose one capacitor over another if they both measure exactly the same? Why wouldn't the designer simply choose the least expensive cap? Why is it that most of the best sounding gear also has the most expensive parts? And, if an expensive component does not use the most expensive parts, then why is it so expensive?

One could extrapolate from the measure-the same position that one would expect two audio components that utilize the same parts (capacitors, resistors, diodes, wire, etc) to have identical specs, and to therefore possess the same sound, yet we would all agree that this is not so.

Exactly....right on target!
I know I sound like a broken record, but this is why I keep going on about the incompleteness of science as a possible explanation for why measurements (as they exist today) are inadequate in describing what we hear. 

Hey,  I'm a simple man, but I am able to use logic and reason.   I'm not saying that I know for sure this is the case, but noone has yet shown me why it is not a reasonable explanation.  And I have yet to see anyone in the measurement camp take this proposition head on.  I see the tap dance and the skirting of the issue.  I hear the argument "measurements don't change, therefore there is no sonic change".  But this is fallacy, and somewhat illogical.  It says we have a set of parameters that we look at and measure.  But it assumes complete accuracy and completess of the science.  How do you know with certainly that the parameter list is 100% complete and fully captures and accurately explains human hearing and perception?

I do believe a physical change occurs with burn-in, and accounts for what we hear.  I also believe science has not yet been able to capture and measure that change properly.  I say measure the "right" thing, focus on some yet unknown and unquantified parameter, and maybe you will see a change.

[Kevin Haskins]

We have two caps by different manufacturers.
They test identical and have the same exact specs.
That is, they measure exactly the same in all regards.
Do you propose that they sound exactly the same?

An excellent point. Why does a designer of audio electronics choose one capacitor over another if they both measure exactly the same? Why wouldn't the designer simply choose the least expensive cap? Why is it that most of the best sounding gear also has the most expensive parts? Why are there so many capacitors that measure the same offered by different manufacturers at different price points? Is there one right product at the proper price-to-performance ratio, and the others are simply differentiated by marketing?

One could extrapolate from the measure-the same position that one would expect two audio components that utilize the same parts (capacitors, resistors, diodes, wire, etc) to have identical specs, and to therefore possess the same sound, yet we would all agree that this is not so.

A lot is marketing.  There are also a lot of reasons besides price upon which to choose a product.   Availability, consistency, reputation of  the manufacture, lifetime expectancy, cosmetics and potential vendor relationships all play into the decision.

Also... I would argue that if you took all the relevant measurements for a given component and they where the same the products WOULD sound the same.   After all the ear is just a inconsistent measuring device.

[AB]

We would all agree that "warm up" exists, no?

So, are there any data that supports the changes we hear before and after "warm up"?

I don't know, that's why I ask.

[Dan Banquer]

We have two caps by different manufacturers.
They test identical and have the same exact specs.
That is, they measure exactly the same in all regards.
Do you propose that they sound exactly the same?

An excellent point. Why does a designer of audio electronics choose one capacitor over another if they both measure exactly the same? Why wouldn't the designer simply choose the least expensive cap? Why is it that most of the best sounding gear also has the most expensive parts? Why are there so many capacitors that measure the same offered by different manufacturers at different price points? Is there one right product at the proper price-to-performance ratio, and the others are simply differentiated by marketing?

One could extrapolate from the measure-the same position that one would expect two audio components that utilize the same parts (capacitors, resistors, diodes, wire, etc) to have identical specs, and to therefore possess the same sound, yet we would all agree that this is not so.

A lot is marketing.  There are also a lot of reasons besides price upon which to choose a product.   Availability, consistency, reputation of  the manufacture, lifetime expectancy, cosmetics and potential vendor relationships all play into the decision.

Also... I would argue that if you took all the relevant measurements for a given component and they where the same the products WOULD sound the same.   After all the ear is just a inconsistent measuring device.

There a few measurements on capacitors that some folks my not be aware of besides capacitance. Measurements such as ESR which is the equivalent series resistance for a given frequency, this will include not only just resistance, but capacitive reactance as well as series inductance. There is also leakage current, (parallel resistance) and if the cap is polarized there are biasing issues. And last but not least dissipation factor.
                       d.b.

[Kevin Haskins]

We would all agree that "warm up" exists, no?

So, are there any data that supports the changes we hear before and after "warm up"?

I don't know, that's why I ask.

Yes.... devices warm up and their properties change during that process.   Whether or not it makes an audible difference would depend upon the device.

I think what is at doubt by those who trust "common audio knowledge" and those who "embrace objective measurements" is that a lot of common knowledge is not necessarily correct.    The level of support needed for something to become "common audio knowledge" is only that it needs to be reported by audio magazines and individuals that hold no standard of proof for their belief.    The objectivist crowd hold that there has to be a standard before we accept something as fact.    That standard tends to include the ability to quantify something, it includes the repeatability of a claim and it includes peer review by others to confirm or deny a claim.    The common knowledge proof has none of those features and the believability of human perception as the sole claim to credibility is a weak one for anyone who has studied human perception.

[ctviggen]

As a major believer in objectivenism, I do wonder if it's possible that we don't have enough data.  For instance, why is it that amplifiers with seemingly the same objective performance characteristics (distortion, power output, sensitivity) can sound different?  Perhaps we don't have all the information we need to determine objectively differences between amplifiers (and other equipment, including burn in)?

[Daygloworange]

I think what is at doubt by those who trust "common audio knowledge" and those who "embrace objective measurements" is that a lot of common knowledge is not necessarily correct.    The level of support needed for something to become "common audio knowledge" is only that it needs to be reported by audio magazines and individuals that hold no standard of proof for their belief.    The objectivist crowd hold that there has to be a standard before we accept something as fact.    That standard tends to include the ability to quantify something, it includes the repeatability of a claim and it includes peer review by others to confirm or deny a claim.    The common knowledge proof has none of those features and the believability of human perception as the sole claim to credibility is a weak one for anyone who has studied human perception.

Very well put. I think that, that is where it becomes a hot topic. Ears are not a measuring device. And not even a repeatable source or barometer. For those that are more akin to hard numbers, then they are more prone to eschew anything that is strictly perceived by humans using their 5 senses. It can't be put on a scale in absolute terms.

But it is human perception that is what guide us to investigate certain matters.

Perhaps the reason no one studied it in depth in the first place, is because scientific types just assumed that if it measures the same on the given state of the art equipment at the time, then it was taken for granted that it is a non issue. What measures the same, sounds the same. And then became the status quo till some people who didn't know any better found differences that( by the numbers) shouldn't have been there.

There were theories on Black Holes and the pyramids, and the Big Bang theory that I was taught in school more or less as gospel that have been challenged numerous times. Science has not stopped evolving, so hypothetically there might still be a lot to learn about the little questions that nag us as pertaining to audio.

It's also possible that we find out the differences are so minuscule that they don't account for the "break in phenomenon" or that the are large enough to actually hear, but to no appreciable level, or that yes, in fact they are there, and are clearly perceived by some and not others.

The quest for answers fascinates me as much as the results do.

Cheers

[Kevin Haskins]

As a major believer in objectivenism, I do wonder if it's possible that we don't have enough data.  For instance, why is it that amplifiers with seemingly the same objective performance characteristics (distortion, power output, sensitivity) can sound different?  Perhaps we don't have all the information we need to determine objectively differences between amplifiers (and other equipment, including burn in)?

I'm sure we could measure it.   What we don't know with 100% certainty is which parameters to give weight to.    A simple THD measurement is a combination of different types of distortion under a fixed operting condition.    Music is a more complex load that is playing into a dynamic impedance (the loudspeaker) so you would need a much more complex set of measurements to fully capture a picture of what is going on.    Then you would need to have a very good understanding of which types of distortion are most audible and a complete understanding of human hearing and perception.    It is a lot of data to analyze and the amount of research necessary to make sense of all of it would be VERY expensive and not necessarily profitable.   High-end audio is a minute portion of the industry and the small companies who participate just don't have the resources to completely study it in detail.    That doesn't mean its not quantifiable, just not cost effective to do all the reasearch if it doesn't pay off in terms of greater sales.   

[Dan Banquer]

As a major believer in objectivenism, I do wonder if it's possible that we don't have enough data.  For instance, why is it that amplifiers with seemingly the same objective performance characteristics (distortion, power output, sensitivity) can sound different?  Perhaps we don't have all the information we need to determine objectively differences between amplifiers (and other equipment, including burn in)?

I'm sure we could measure it.   What we don't know with 100% certainty is which parameters to give weight to.    A simple THD measurement is a combination of different types of distortion under a fixed operting condition.    Music is a more complex load that is playing into a dynamic impedance (the loudspeaker) so you would need a much more complex set of measurements to fully capture a picture of what is going on.    Then you would need to have a very good understanding of which types of distortion are most audible and a complete understanding of human hearing and perception.    It is a lot of data to analyze and the amount of research necessary to make sense of all of it would be VERY expensive and not necessarily profitable.   High-end audio is a minute portion of the industry and the small companies who participate just don't have the resources to completely study it in detail.    That doesn't mean its not quantifiable, just not cost effective to do all the reasearch if it doesn't pay off in terms of greater sales.   

I am going to be addressing this and a few other issues in an upcoming article on Negative Feedback for Audioholics.
             d.b.

[Daygloworange]

Kevin,

Thank you for that. Again well said. I've always maintained that music is not static,it is rising and falling, and rolling and tumbling. Firing pink or white noise, or sine waves and measuring it is not going to give you everything that you can possibly measure, and therefore not give you all the data. Therefore using the same logic as a diehard number cruncher, one cannot concluded that it is conclusive.

But you may have shed the most important clue. It is not a profitable enough venture to go seeking the answers. It may be that for the vast majority of uses for these electronic items, that the differences would not matter for the majority of people, so there is no market it for it.

In that case, there is no need or demand for it, then it's a non issue. But, that doesn't mean it doesn't exist.

If there was a magic wire or capacitor that nobody would buy. It wouldn't be around. But it would still exist.

Cheers

[Daygloworange]

I am going to be addressing this and a few other issues in an upcoming article on Negative Feedback for Audioholics.

Cool. Could you post the link here when you do?

Cheers

[fredgarvin]

There is no magic. Just what is imposed by expectation and an always changing subjective perception. there are plenty of folks that believe in magic, however.

[Kevin Haskins]

Kevin,

Thank you for that. Again well said. I've always maintained that music is not static,it is rising and falling, and rolling and tumbling. Firing pink or white noise, or sine waves and measuring it is not going to give you everything that you can possibly measure, and therefore not give you all the data. Therefore using the same logic as a diehard number cruncher, one cannot concluded that it is conclusive.

But you may have shed the most important clue. It is not a profitable enough venture to go seeking the answers. It may be that for the vast majority of uses for these electronic items, that the differences would not matter for the majority of people, so there is no market it for it.

In that case, there is no need or demand for it, then it's a non issue. But, that doesn't mean it doesn't exist.

If there was a magic wire or capacitor that nobody would buy. It wouldn't be around. But it would still exist.

Cheers

The main problem is that in the absence of an objective standard snake oil and scams tend to thrive.   Whenever something cannot be quantified it opens up the field for snake-oil and those less savory individuals and companies willing to exploit people.   It opens up wild claims with little to support them.    That is pretty much the atmosphere we have in high-end audio these days.    That type of atmosphere doesn't lend itself to improving products.   It doesn't lend itself to the advancement of the art.

[PhilNYC]

Wow...posted this topic yesterday, and there's already 12 pages of responses!  Interesting discussion...but quite honestly, only 2-3 responses have actually answered my question...

Am still curious as to whether those who assert that burn in is usually a case of someone "getting used to the sound" rather than any real change in the sound actually hear those changes themselves.  In other words, are non-believers hearing changes that they attribute to their hearing adjusting?  Or do they simply not hear any changes over time?