scott wurcer said:
Normally during the operationalisation the test designer is thinking about the problem/thesis that should be studied and about the appropriate methods to deal with all possible confounders.
In the end the scientifically approved method is to use positive and negative controls to ensure that the results are _really_ based mainly on audible differences.
It is beyond my understanding why in audio tests controls are so often omitted.
Jam,
I maintain that anyone who claims that others have stolen, copied or reverse engineered a circuit or design, that has NEVER been published anywhere, is not only misleading himself, but also others who are made to belief he should be given credit for it.
This is, of course, why my current business partner hates to see me contributing here. Why, indeed, should I answer questions and argue with 'non-believers' only to get copied and rebuked in the end? This is not the first time I have been through this.
Mark Levinson dropped me, ( and the majority of my royalties) once he had the bulk of the intellectual information that I contributed over a period of 3 years.
Over the years, I have constantly complained about people using my design knowledge, and then I realized that I enjoyed showing off with it.
Before the internet, people would just' buy me lunch' and run off with the input. Now I get demands for schematics and answers to even confidential info (to me).
Please remember there are 3 phases to an idea:
It won't work.
It works, but it is not important.
We invented it.
We are now between 2 and 3 with the Blowtorch.
Mark Levinson dropped me, ( and the majority of my royalties) once he had the bulk of the intellectual information that I contributed over a period of 3 years.
Over the years, I have constantly complained about people using my design knowledge, and then I realized that I enjoyed showing off with it.
Before the internet, people would just' buy me lunch' and run off with the input. Now I get demands for schematics and answers to even confidential info (to me).
Please remember there are 3 phases to an idea:
It won't work.
It works, but it is not important.
We invented it.
We are now between 2 and 3 with the Blowtorch.
I apologise up front for stealing the thread, briefly.
I believe the 2-JFET source follower circuits originate from John, and hope to hear some critical remarks from you all.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128571
Thanks in advance.
Patrick
I believe the 2-JFET source follower circuits originate from John, and hope to hear some critical remarks from you all.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128571
Thanks in advance.
Patrick
john curl said:
Sell the schematic and parts list to the highest bidder on E-bay. With a healthy reserve.
Don't include that ballet picture.
Emitter Degeneration?
I seem to recall reading somewhere written by someone that I can not presently recall where he did tests of FETs set up with various amounts of emitter degeneration, and showed the harmonic spectra that were produced as a result.
Could this be a consideration when trying to use degeneration of a given stage as a volume control?
_-_-bear
PS. I once knew something of value, but I forget what it was...
I seem to recall reading somewhere written by someone that I can not presently recall where he did tests of FETs set up with various amounts of emitter degeneration, and showed the harmonic spectra that were produced as a result.
Could this be a consideration when trying to use degeneration of a given stage as a volume control?
_-_-bear
PS. I once knew something of value, but I forget what it was...
quote:
"What we have here is a failure to communicate" Some here actually believe that ABX testing will separate what is truly audible from what only appears to be audible. We have been at this for 30 years. Unfortunately, ABX testing tends to merge subtle differences beyond frequency response and a certain significant distortion threshold (like clipping) into confusion...........
John, if (double) blind testing 'tends to merge subtle differences . . . . into confusion' then it is not the blind test that doing it . . its the human interpretation. You could then rightly argue that if the test was leading to confusion between the units under test, or indeed the interpretation of what was being heard, it might be that the differences were not that great to start off with - i.e. significant enough to be certain.
The reason for doing a double blind test is to remove participant bias.
If I put two amplifiers in front of an individual and one looks a whole lot better than the other and costs 5 times as much, even though the electrical performance might be the same, most people will say the more expensive amp sounds better. This is why $150 bottle of red wine always tastes better than $40 bottle. It may jerk a few people off here, but this is how the human brain works. Its also why $99 sounds like more of a bargain than $101 - even though the delta is only about 2% etc.
On another subject, I agree with your points (and Pavel's) about not disclosing your circuits BTW - there are too many people willing to rip off other people's ideas to make a quick buck.
"What we have here is a failure to communicate" Some here actually believe that ABX testing will separate what is truly audible from what only appears to be audible. We have been at this for 30 years. Unfortunately, ABX testing tends to merge subtle differences beyond frequency response and a certain significant distortion threshold (like clipping) into confusion...........
John, if (double) blind testing 'tends to merge subtle differences . . . . into confusion' then it is not the blind test that doing it . . its the human interpretation. You could then rightly argue that if the test was leading to confusion between the units under test, or indeed the interpretation of what was being heard, it might be that the differences were not that great to start off with - i.e. significant enough to be certain.
The reason for doing a double blind test is to remove participant bias.
If I put two amplifiers in front of an individual and one looks a whole lot better than the other and costs 5 times as much, even though the electrical performance might be the same, most people will say the more expensive amp sounds better. This is why $150 bottle of red wine always tastes better than $40 bottle. It may jerk a few people off here, but this is how the human brain works. Its also why $99 sounds like more of a bargain than $101 - even though the delta is only about 2% etc.
On another subject, I agree with your points (and Pavel's) about not disclosing your circuits BTW - there are too many people willing to rip off other people's ideas to make a quick buck.
Bonsai said:
The reason for blind testing is to remove a certain type of participant bias and double blind testing is done to remove a certain type of influence of the experimentators.
There is whole bunch of possible other confounders (biases) that must be addressed and is quite often not in audio tests.
Just for example, what about the expectation bias of participants knowing that they will/should hear the difference between SACD and 16bit/44.1kHz?
In a scientifically sense it can be much better to let participants not know what topic will be tested.
But of course even then listeners will expect something (humans seem always to await something 🙂 )
There is a whole bunch of literature about proper testing (cognitive psychology) and it should be mandatory for every audio test designer to read a lot of these first. 🙂
There are so many points to consider during the operationalisation phase and a lot of these can have impact on the results.
Thats the reason why you must use positive and negative controls in these tests to confirm that your listeners have reached a sufficient level of sensitivity and on the other hand that the results are _really_ based on _audible_ differences.
Bonsai said:
In order to validate your hypothesis, wouldn't it be a nice experiment when one performs a sighted AB test with identical amps, but housed in different cabinets, one ugly and one beautiful? Perhaps it has already been done. Does anybody know of such experiment?
Re: Emitter Degeneration?
Hi Bear,
That's Cordell's findings for bipolars :
http://www.diyaudio.com/forums/showthread.php?postid=1557595#post1557595
bear said:
Hi Bear,
That's Cordell's findings for bipolars :
http://www.diyaudio.com/forums/showthread.php?postid=1557595#post1557595
There are 2 kinds of bias:
One is hearing something that doesn't exist.
The other is NOT hearing something that does exist.
ABX testing is not balanced between these two kinds of bias. In fact, it is skewed toward NOT hearing differences. That is its problem. We have discussed this for 30 years. I have personally discussed this at length with Lipshitz, Toole, Clark, and many others, at length over the decades.
They have NEVER addressed my objections, even when they were obvious.
This is why I don't bother with ABX testing anymore.
One is hearing something that doesn't exist.
The other is NOT hearing something that does exist.
ABX testing is not balanced between these two kinds of bias. In fact, it is skewed toward NOT hearing differences. That is its problem. We have discussed this for 30 years. I have personally discussed this at length with Lipshitz, Toole, Clark, and many others, at length over the decades.
They have NEVER addressed my objections, even when they were obvious.
This is why I don't bother with ABX testing anymore.
I wrote in another thread, that ABX is to be scientifically and politically correct. It defies the purpose of making equipment for personal use. IMHO of course.
Its just in the nature of aural perception and sonic culture of the individual (and culture level in general) that audio performance experience can not be transmitted with literature or a set of measurements if main things are done right enough, above the threshold of electrical and acoustical gross mistakes.
So either one knows JC and had listens and discussions with him, or had experienced his designs as a customer for long in different combination so to know where he comes from when he says ''resistors have a sound'' for instance.
Science is very right to look for reference and statistics. Needs a set of universal tools. ABX is OK for what it is. To check if something is objectionable or colored. To me, such tools that are excluding the normal personal experience with all its human biases are honest practical ways to be fair as a scientist. They are great to know that public address or mass market equipment will not be objectionable to the average indifferent ear. Nothing will provoke or stick out sonically.
To me ABX is biased towards indifference. It strips all the individual luxury and clues.
Its just there is so much opportunism around, that if JC for instance says that he had to look for the best TKD pot for blowtorch because pots do have a sound, a multitude of non engineers find a way to ''design'' and sell by just cooking components. And they can proudly say ''Even JC confirms, its all in the components, I will upgrade your amp with this and that $$$ cable, cap, resistor''.
So sticking with what science has given us for audio toolbox is very sensible and protects the consumers educationally from snake oil, on the other hand it slanders some honest free spirited breakouts.
I knew that science explains experiment, not predicts experiment. So having a small toolbox, means not dare experiencing outside it?
Its just in the nature of aural perception and sonic culture of the individual (and culture level in general) that audio performance experience can not be transmitted with literature or a set of measurements if main things are done right enough, above the threshold of electrical and acoustical gross mistakes.
So either one knows JC and had listens and discussions with him, or had experienced his designs as a customer for long in different combination so to know where he comes from when he says ''resistors have a sound'' for instance.
Science is very right to look for reference and statistics. Needs a set of universal tools. ABX is OK for what it is. To check if something is objectionable or colored. To me, such tools that are excluding the normal personal experience with all its human biases are honest practical ways to be fair as a scientist. They are great to know that public address or mass market equipment will not be objectionable to the average indifferent ear. Nothing will provoke or stick out sonically.
To me ABX is biased towards indifference. It strips all the individual luxury and clues.
Its just there is so much opportunism around, that if JC for instance says that he had to look for the best TKD pot for blowtorch because pots do have a sound, a multitude of non engineers find a way to ''design'' and sell by just cooking components. And they can proudly say ''Even JC confirms, its all in the components, I will upgrade your amp with this and that $$$ cable, cap, resistor''.
So sticking with what science has given us for audio toolbox is very sensible and protects the consumers educationally from snake oil, on the other hand it slanders some honest free spirited breakouts.
I knew that science explains experiment, not predicts experiment. So having a small toolbox, means not dare experiencing outside it?
salas said:
Hi salas,
I agree that ABX 'strips the individual etc clues'. But it is supposed to do that. ABX is not about which amplifier or speaker gives the most pleasure to the user. If we would want to know that, we would need to take into account all the other things that have been mentioned ad nauseatum, like price, color, size, who build it, etc. Such a test, btw, would be easy. Just compare the number of units sold 😉
But we don't want to know which component gives the most pleasure, in this instance. We want to know if two components *sound* differently. Therefore, we *must* strip the test from every personal luxury. If we don't do that, the test is worthless.
Jan Didden
john curl said:
John,
That is true, but can be circumvented I think. For instance, if you would want to test a Blowtorch against a 100 $ Sony receiver, it's a safe bet that IF you were biased, it would be bias towards hearing a difference. So, if you would do a DBT and not identify statistically significant the equipment, wouldn't that be a valid and important outcome?
Jan Didden
janneman,
Exactly, its in my text too. ABX is ''In Vitro''. Good for what it is. Its a statistical reference tool. In statistics you can have a main idea. There it ends.
To me, tools are picked and used best when knowing what is the goal. I just highlight that life is not isolated, and excellent equipment targeting personal domestic use are beyond being politically correct. Don't you just hate it that a whole snake oil industry is based on that? I do. But that's life. It would not be like that if life isn't like that. We can't protect the gullible and we must search hard for the genuine item. Wasn't always like that in human history?
Exactly, its in my text too. ABX is ''In Vitro''. Good for what it is. Its a statistical reference tool. In statistics you can have a main idea. There it ends.
To me, tools are picked and used best when knowing what is the goal. I just highlight that life is not isolated, and excellent equipment targeting personal domestic use are beyond being politically correct. Don't you just hate it that a whole snake oil industry is based on that? I do. But that's life. It would not be like that if life isn't like that. We can't protect the gullible and we must search hard for the genuine item. Wasn't always like that in human history?
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