I suspect that Sig Linkwitz isn't spending too much time painting goop on knobs or freezing his CDs!
In any case, Fred, the factors you name are well-known in sensory research. Yes, people sometimes do design tests badly- that's why it's silly to take the null results of one test and generalize from it. But when test after test after test, done by various people using various control methodologies, keep piling up one null result after another, at a certain point, one has to say that when it comes to boxes of gain, there don't seem to be any factors lying outside of conventional engineering which can be audibly distinguished.
A question for you; you mentioned the possibility of piezoelectric effects from SiO2 passivations in chips. I'm curious if there's any experimental evidence of that; as far as I'm aware, the lack of symmetry in the amorphous form (which is what results from passivation and CVD) would exclude this as a possibility.
Could that SiO2 somehow crystallize in normal processing and use? Quoting from one of your links:
"Unlike e.g. amorphous silicon, amorphous silicon dioxide will not crystallize upon annealing at normal temperatures. ("Devitrification" -- that is, crystallization -- of quartz furnace tubes used for high-temperature oxidation is sometimes observed after thousands of hours of use at temperatures exceeding 1200 C.) "
In any case, Fred, the factors you name are well-known in sensory research. Yes, people sometimes do design tests badly- that's why it's silly to take the null results of one test and generalize from it. But when test after test after test, done by various people using various control methodologies, keep piling up one null result after another, at a certain point, one has to say that when it comes to boxes of gain, there don't seem to be any factors lying outside of conventional engineering which can be audibly distinguished.
A question for you; you mentioned the possibility of piezoelectric effects from SiO2 passivations in chips. I'm curious if there's any experimental evidence of that; as far as I'm aware, the lack of symmetry in the amorphous form (which is what results from passivation and CVD) would exclude this as a possibility.
Could that SiO2 somehow crystallize in normal processing and use? Quoting from one of your links:
"Unlike e.g. amorphous silicon, amorphous silicon dioxide will not crystallize upon annealing at normal temperatures. ("Devitrification" -- that is, crystallization -- of quartz furnace tubes used for high-temperature oxidation is sometimes observed after thousands of hours of use at temperatures exceeding 1200 C.) "
"A question for you; you mentioned the possibility of piezoelectric effects from SiO2 passivations in chips. I'm curious if there's any experimental evidence of that; as far as I'm aware, the lack of symmetry in the amorphous form (which is what results from passivation and CVD) would exclude this as a possibility.
From:
http://www.azom.com/details.asp?ArticleID=1114#_Piezoelectrics
Quartz has this property as it has a complicated crystal structure with a low degree of symmetry.
I don't know. I would think it would certainly be much less piezoelectric than crystalline form which exhibits a high degree of piezoelectric effect evidenced by it's use crystal oscillators.
Fred
Dieckmann /not a semiconductor physicist and doesn't even play one on the web
From:
http://www.azom.com/details.asp?ArticleID=1114#_Piezoelectrics
Quartz has this property as it has a complicated crystal structure with a low degree of symmetry.
I don't know. I would think it would certainly be much less piezoelectric than crystalline form which exhibits a high degree of piezoelectric effect evidenced by it's use crystal oscillators.
Fred
Dieckmann /not a semiconductor physicist and doesn't even play one on the web
You bring up a good point. As I said, I haven't ruled it out and both SY and I suggested Peter test it.Fred Dieckmann said:
And who's to say a pilot of a 747 cannot detect some bird droppings on the wing from the way the plane handles? I'm sorry, someone needs to do the math to demonstrate this is anything but a red herring. It's really hard to imagine that the tempco effects (which are really tiny to begin with) combined with any dynamic heating effects (which are going to be small to non-existant depending on how the resistor is sized and its location in the circuit), combined with the effect a change in that resistor's value actually has on the amplifier after feedback, won't be anything but a percentage so small that gamma rays from another galaxy probably have a greater effect on the amplifier. But, if you can come up with some real-world math to show me otherwise, I'll try to keep an open mind.Fred Dieckmann said:
Re: cosinusoids...
So? All you're saying here is that an impulse can be described mathematically. Which has never been in dispute as far as I'm aware.
The question, again, is how do you evaluate an amplifier's impulse response using a single, steady state sinusoid as the stimulus?
se
mikek said:
So? All you're saying here is that an impulse can be described mathematically. Which has never been in dispute as far as I'm aware.
The question, again, is how do you evaluate an amplifier's impulse response using a single, steady state sinusoid as the stimulus?
se
Can someone tell me if there's a thread on this topic somewhere? It sounds interesting!SY said:
Re: cosinusoids...
....using pspice without understanding its limitations, the underlaying circuit theory, how it arrives at results, and real world ramifications of its short comings amounts to cooking with a blindfold....
Fred Dieckmann said:
....using pspice without understanding its limitations, the underlaying circuit theory, how it arrives at results, and real world ramifications of its short comings amounts to cooking with a blindfold....
Re: Re: cosinusoids...
..... we are yet to have arbitrary waveform generation in pspice......?
Fred Dieckmann said:
..... we are yet to have arbitrary waveform generation in pspice......?
Re: Re: Truly Amazing ........
Fred, thanks for providing some constructive points that can be addressed.
Tom Nousaine has set up a number of self-professed golden-eared audiophiles with an ABX comparator in their own home using their own system and allowed to run tests at their own leisure over periods of months or more.
So far, none have been able to statistically discern any differences once basic issues such as distortion, frequency response and level matching have been addressed.
If you agree psychological factors are an issue, how do you suggest they be removed for accurate comparisons? If you tell me you have superhuman control of your mind and can ignore them, it will be my turn to laugh.
You appear frustrated by what you call "cynical presumptions" by folks who want objective evidence. I'm frustrated by subjective folks, who against all the objective evidence, against even common sense, insist they can hear things that have been shown time and time again, in a variety of ways, don't exist. Or, in a more general sense, they insist they're somehow exempt from well documented psychological behavior. Worse, they often refuse to participate in a blind test--at least one that can be verified by an unbiased third party. I wonder why?
I'm NOT criticizing your listening skills--I have no idea how skilled you are in that area. I've particpated in blind tests where one listener can pick out a piece of gear with 100% accuracy and someone else in the exact same session cannot manage better than random. Interestingly, this seems especially true with perceptual encoding (i.e. MP3, MD, etc.). Some people are sensitive to throwing away part of the audio signal, and some aren't. But none of this invalidates blind testing. It only matters what YOU can hear (assuming you're building/buying for yourself).
If you're designing a piece of gear to be sold or enjoyed by many, then it makes sense to have many listen to it during the development process. This is true for blind or non-blind listening tests. The blind ones are just much more likely to produce accurate results.
Fred, thanks for providing some constructive points that can be addressed.
Well that's good to hear at least.Fred Dieckmann said:
Who's asking you (or anyone else) to do that? If you're saying you don't trust someone else to set up the test properly, that's a pretty weak argument--especially when you're welcome to set up the test yourself in your own system. You only need another person to assist with the blind switching and record keeping. If you don't trust them, have someone supervise them if you'd like? If I misunderstood the question, please let me know.Fred Dieckmann said:
I'm not proposing that. I'm proposing that people design the test to determine if differences exist between two pieces of gear (or capacitors, or whatever). The outcome can go either way. I'm suggesting people use their own systems, their own music, etc. The number of variables changed from how you normally listen now are minimal.Fred Dieckmann said:
Well see above relative to the system, as to anxiety, etc, it needn't be much greater than any other non-blind critical listening test. And again, I have to say if the differences or so subtle that having someone else in the room causes you not to hear them, how significant are they? For more on the above, and the issue of time, I quote from post #15 in this thread by Steve Eddy:Fred Dieckmann said:
Tom Nousaine has set up a number of self-professed golden-eared audiophiles with an ABX comparator in their own home using their own system and allowed to run tests at their own leisure over periods of months or more.
So far, none have been able to statistically discern any differences once basic issues such as distortion, frequency response and level matching have been addressed.
See the answer to point number 2 above. I'm suggesting people do these tests in their own systems. If they can or cannot hear a difference in their own system, with their own ears, with their own music, isn't that what matters most?Fred Dieckmann said:
Well here's where the null test can be really useful. If you can show different null test results at different times of the day, then I'll conceed some of the above MIGHT have an audible effect. But I've run lots of comparison null tests and they never seem to vary by time of day. Our EARS certainly change by time of day and that is a much more likely explanation.Fred Dieckmann said:
I can't speak for everyone, but all I'm suggesting is this: If things people hear cannot continue to be heard when they don't know what they're listening to, they're VERY LIKELY caused by those psychological factors you agreed exist at the top of the post.Fred Dieckmann said:
If you agree psychological factors are an issue, how do you suggest they be removed for accurate comparisons? If you tell me you have superhuman control of your mind and can ignore them, it will be my turn to laugh.
You appear frustrated by what you call "cynical presumptions" by folks who want objective evidence. I'm frustrated by subjective folks, who against all the objective evidence, against even common sense, insist they can hear things that have been shown time and time again, in a variety of ways, don't exist. Or, in a more general sense, they insist they're somehow exempt from well documented psychological behavior. Worse, they often refuse to participate in a blind test--at least one that can be verified by an unbiased third party. I wonder why?
I'm NOT criticizing your listening skills--I have no idea how skilled you are in that area. I've particpated in blind tests where one listener can pick out a piece of gear with 100% accuracy and someone else in the exact same session cannot manage better than random. Interestingly, this seems especially true with perceptual encoding (i.e. MP3, MD, etc.). Some people are sensitive to throwing away part of the audio signal, and some aren't. But none of this invalidates blind testing. It only matters what YOU can hear (assuming you're building/buying for yourself).
If you're designing a piece of gear to be sold or enjoyed by many, then it makes sense to have many listen to it during the development process. This is true for blind or non-blind listening tests. The blind ones are just much more likely to produce accurate results.
Swords, listening and words...
If you want to talk about people running around sharing their knowledge, what about all the people who claim to evaluate an amplifier having only heard it in an unknown system? I run into that all the time. For example:
"Yeah, I stopped into Snake Oil Audio for the first time yesterday and listened to the new XA3000 Pass amp and MAN did it sound good!"
How rational is that? Yeah, the SYSTEM they heard may have sounded really good, but HOW ON EARTH did they attribute the good sound to the amplifier??? What about the speakers, do they know exactly how those sound (and when was the last time they heard them)? What about the room? What about the source material? Even most audiophiles will agree all those things are likely to make a much bigger difference than the amplifier.
The above can seemingly only be explained by audiophiles believing they're listening skills are SO superhuman, they're able to somehow exclude the speakers, room, source material, etc. and magically evaluate the sound of the amplifier in the above situation. I'm not saying they all do this, but it happens so often it amazes me.
Well this isn't any different than all the people running around claiming to hear differences that have no objective basis in fact. And the way blind testing works, if you really can't hear anything, for that person at least in that system, it probably means the things being compared really ARE similar enough to be considered to sound identical (in other words a "false null result" would be rare).Peter Daniel said:
If you want to talk about people running around sharing their knowledge, what about all the people who claim to evaluate an amplifier having only heard it in an unknown system? I run into that all the time. For example:
"Yeah, I stopped into Snake Oil Audio for the first time yesterday and listened to the new XA3000 Pass amp and MAN did it sound good!"
How rational is that? Yeah, the SYSTEM they heard may have sounded really good, but HOW ON EARTH did they attribute the good sound to the amplifier??? What about the speakers, do they know exactly how those sound (and when was the last time they heard them)? What about the room? What about the source material? Even most audiophiles will agree all those things are likely to make a much bigger difference than the amplifier.
The above can seemingly only be explained by audiophiles believing they're listening skills are SO superhuman, they're able to somehow exclude the speakers, room, source material, etc. and magically evaluate the sound of the amplifier in the above situation. I'm not saying they all do this, but it happens so often it amazes me.
OK, I'll put you out of your misery- it's not piezoelectric at all. That's a good thing, too, since my cats are often perched near my window while I'm playing music and I'd hate to see them electrocuted by the rattling.
SY/ Formerly a semiconductor physicist/chemist
That's exactly what motivated me to test my own beliefs. I was quite certain of my own extraordinary skills. So were my audio geek buddies, who stopped talking to me afterwards.
I caveat this with the statement that guys like Fred or Frank or Peter are much too smart (seriously) to say silly things like that.
It sounds like you and I are coming from a very similar place. We used to believe in the subjectivist's mantra, and now we're a bit more objective and rational (and subsequently at odds with much of the golden-ear crowd). It's amazing what participating in a few blind tests will do, isn't it?SY said:
Peter raised the concern that someone could somehow have a "false null" result from a blind test and run around telling everyone that all amplifiers sound the same. I think a much greater sin has been (and still is being) committed by all the people running around claiming differences that are based on pure psychological perceptions. That many subjectivists claim to know how an amplifier sounds, in a system unknown to them, is just one of the most obvious examples.
Peter's take is... novel.
I really hope that he takes the time to run some blind tests on his own.
I really hope that he takes the time to run some blind tests on his own.
Re: Re: cosinusoids...
Duh........ I have expressed this view here on many occasions.
I don't advocate it for distortion analysis. Ask around.
Having used it since 1976. The first serious class project was to analyze the was to design see if a given set of performance goals could be met with a stated
topology and transistor choice. Yes, it could, if the Hfe was within a certain range that did not include the full Hfe variation for that part as show on the data sheet. I would have had to do lot of testing on the bench to find that out and have transistors with a large Hfe spread. I got an A on the project.
I guess might have a little experience with it. It has been incredibly useful on countless occasions for filter design, signal integrity, and stability simulations.
I have also seen how poor most of the op amp models are. If you want to see some limitations, go look at IBIS models for signal integrity analysis. We owned a $100,000 from Mentor graphics. It was still a very powerful tool and analysis of large boards and backplanes would be very time consuming. Time to market is very important constraint in the real world.
Spice is to supplement and not to supplant design testing on the bench. I suggest designing without it might be like cooking without a cookbook. I would still taste what I was cooking before subjecting other to the results. I still don't know why your asking if Spice can use arbitrary waveforms. If you are really trying describe a waveform from a description by the equations and find the task so tedious may I recommend MathCad. Spice does have a piece-wise linear input model, but it may not suit your needs. Surely you were suggesting modeling distortion with a complicated input waveform in Spice?
http://newton.ex.ac.uk/teaching/CDHW/Electronics2/userguide/sec3.html#3.2.1.4
I am curious how long you have been using Spice. I am also a little curious if you were even born yet in 1976.
mikek said:
Duh........ I have expressed this view here on many occasions.
I don't advocate it for distortion analysis. Ask around.
Having used it since 1976. The first serious class project was to analyze the was to design see if a given set of performance goals could be met with a stated
topology and transistor choice. Yes, it could, if the Hfe was within a certain range that did not include the full Hfe variation for that part as show on the data sheet. I would have had to do lot of testing on the bench to find that out and have transistors with a large Hfe spread. I got an A on the project.
I guess might have a little experience with it. It has been incredibly useful on countless occasions for filter design, signal integrity, and stability simulations.
I have also seen how poor most of the op amp models are. If you want to see some limitations, go look at IBIS models for signal integrity analysis. We owned a $100,000 from Mentor graphics. It was still a very powerful tool and analysis of large boards and backplanes would be very time consuming. Time to market is very important constraint in the real world.
Spice is to supplement and not to supplant design testing on the bench. I suggest designing without it might be like cooking without a cookbook. I would still taste what I was cooking before subjecting other to the results. I still don't know why your asking if Spice can use arbitrary waveforms. If you are really trying describe a waveform from a description by the equations and find the task so tedious may I recommend MathCad. Spice does have a piece-wise linear input model, but it may not suit your needs. Surely you were suggesting modeling distortion with a complicated input waveform in Spice?
http://newton.ex.ac.uk/teaching/CDHW/Electronics2/userguide/sec3.html#3.2.1.4
I am curious how long you have been using Spice. I am also a little curious if you were even born yet in 1976.
SY said:
Perhaps you can't postulate a hypothesis then, Since I have heard the effect damping material applied to ICs. Much against my expectations and to my chagrin; and with blind testing no less.
Nobody wants to discuss tempco effects in resistors then?
Re: Re: Re: Re: cosinusoids...
Yeah, and we're wandering off topic again. Fred seems bent on touting his vast experience, and/or discrediting the abilities of others, rather than debating the issues at hand although we're making some progress on the thread topics.SY said:
I'm not sure I understand, Jorge. Is the diff amp not always within the feedback loop whether in inverting or non-inverting config as the diff amp is just that - a difference between one input and the other. No matter which input you use for the source signal, the current fed back will be related to the difference between the inputs.
BLIND TESTING???? I thought you were OPPOSED to blind testing? All you've done is say bad things about it and the people who advocate it. Why were you using it yourself if it's so flawed in your eyes?Fred Dieckmann said:
As to tempco, I already commented, you must have missed it.
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