A small problem, at least to me, is that the same people are unable to tell the difference in DBT tests where real differences between sample files are in 3 - 4 orders higher (re non-linearity). And again the same people can perfectly tell the difference between 2 absolutely same files (with different file names) in a sighted open test. So what is the value of such opinions?
It starts with refraining from using misleading terms. "Ears only" does not exist (most likely) so an alleged "ears only" is only a different kind of "ears with brain" than it is in the case of "sighted" listening tests.
Afair JC argued that differences "disappear" if he uses an ABX test protocol but not when using an A/B method.
As perfect tests don´t exist (most likely) and perfect documentation does not exist either (most probably) we have to conclude that all experiments/tests are "sloppy" up to a certain degree.
Evaluation of this "sloppiness" should not be guided by the degree that you like the results.
If you analysize the results of well documented controlled listening experiments you´ll notice that the chance to get positive results when evalutating "questionable effects" is much higher if propper training (including accomodation time) of participants was incorporated.
Notwithstanding sort of replication crisis exists in the audio field too.
So many are wrong in DBLT? I already said I cant tell much in that test either. But do in other ways.... Basically A-B. Consistently. Unsighted. Not good enough? Sorry that's all i have for you then. Short of showing and teaching you my way together -- one on one. DBT/ABX are great for somethings.
----------------------------------------------
Here is an example of ignoring parasitics in a speaker cross-over design -->
take that nice 90 degree from a film, i showed you. Add 18 inches of wire in series with it. Not much L or R, but here is same cap with 18 inches of wire added:
Double the length and you are at 70 degrees/5KHz. A bi-polar would be a lot worse to begin with.
Anyone here using wire from driver to cross-over that length or longer? And what does it look like with a length of speaker cable added?
Any wonder when in-play the perfect cross-over doesnt always add or subtract like you wanted it to be in CAD or even on the test bench? So you start tweeking and fudging values to get it to sound/measure better? Small details again.
measure your passive cross-over from PA output and at the driver terminal through the cable and wires. And, yes the load Z matter and affects this result or high z or low z but also larger C values etc. cant be exact without specifics.
Similar if you measure at the pcb or at the power supply when the HF bypass is located some distance from the circuit thru power wires/harness. How many times do we see bypass on the big filter caps and then wire off from there to the circuitry. The bypass needs to be at the PCB/circuit if you want low HF Z to common.
THx-RNMarsh
----------------------------------------------
Here is an example of ignoring parasitics in a speaker cross-over design -->
take that nice 90 degree from a film, i showed you. Add 18 inches of wire in series with it. Not much L or R, but here is same cap with 18 inches of wire added:
Double the length and you are at 70 degrees/5KHz. A bi-polar would be a lot worse to begin with.
Anyone here using wire from driver to cross-over that length or longer? And what does it look like with a length of speaker cable added?
Any wonder when in-play the perfect cross-over doesnt always add or subtract like you wanted it to be in CAD or even on the test bench? So you start tweeking and fudging values to get it to sound/measure better? Small details again.
measure your passive cross-over from PA output and at the driver terminal through the cable and wires. And, yes the load Z matter and affects this result or high z or low z but also larger C values etc. cant be exact without specifics.
Similar if you measure at the pcb or at the power supply when the HF bypass is located some distance from the circuit thru power wires/harness. How many times do we see bypass on the big filter caps and then wire off from there to the circuitry. The bypass needs to be at the PCB/circuit if you want low HF Z to common.
THx-RNMarsh
Last edited:
<snip>
If you mean that, by taking a result measured with a significant AC drop across the capacitor which can be seen to be below the noise floor of the room and extrapolating that to say that, with no AC drop across it in a coupling application then the distortion will be , to quote SY '73% of **** all', then yes absolutely guilty as charged
That´s why i wrote using the implied correctness of your model theory as a premise is dangerous because you never know if it´s correct.
You´ve to assume that Cyrill found everything that matters, that it is representative for all usuable capacitors and that his measurement setup reflects correctly every variable introduced by real world applications.
A small problem, at least to me, is that the same people are unable to tell the difference in DBT tests where real differences between sample files are in 3 - 4 orders higher (re non-linearity). And again the same people can perfectly tell the difference between 2 absolutely same files (with different file names) in a sighted open test. So what is the value of such opinions?
But why it is? Doesn´t something like that happen quite often in every day life?
You have to sort out people who you don´t trust (in some ways) and to rely more on the opinion of people who are reasonable.
If somebody recommends a good restaurant to you, you most likely will not ask him if he did some good sensory evaluation test nor you´ll ask him if he did analyse the food in a competent labor, but instead it will be more important if his habits/tast suits yours or not.
But that you´ll never know without trying (and it would be absolutely the same if he did some propper "blind" tasting or chemical analysis)....
Jakob: Sorry I thought it was clear in my first part of that post that I was just looking at HD caused by a cap in in a blocking application. I certainly would not infer that there are not other mechanisms at play (such as leakage) that would need to be considered.
Of course there are effects that are not taken into account, but right now in my system with things I am building I don't have a need to worry about them. Then again I am only pleasing myself (and the good lady) with my system and have no intention of claiming my stuff is better than anything.
Of course there are effects that are not taken into account, but right now in my system with things I am building I don't have a need to worry about them. Then again I am only pleasing myself (and the good lady) with my system and have no intention of claiming my stuff is better than anything.
Even if true this does not mean DA is the cause, but merely that DA is well-correlated with the effect. You would need to find some nonlinearity in DA (which others have failed to find) or some other dielectric problem which just happens to correlate well with DA.RNMarsh said:
Shooting the messenger is a well-established method for dealing with unfortunate facts.
Sorry, you can decide what is audible or not only with your ears. Distortion with continuous signal is not the only think your ears+brain is sensible to.
If the distortion of a cap is higher than what I consider as acceptable, I will not even listen to. What about you ?
It as been the previous object of several vehement discussions here. All along with topologies, LTP vs Current feedback etc.
On my side, "I tend to prefer" FETs for output devices. because they are fast and no secondary breakdown. But I agree it is sad that they become hard to provision
By the way, nobody pretended: "bipolar electrolytic are horrible". The discussion was painful enough to not aggravate it with caricatures.
Somewhat on-topic. Was cleaning out stuff, found my notes from a distant AES convention, a presentation on capacitor non-linearities resulting from - gasp - electro-mechanical forces in a wound film cap. I cannot remember the presenter but it was possibly Clarity cap.
The measurements were done on a 4.7uF wound film xover cap with a laser vibro-meter.
My notes say:
Measured mechanical effects at the top of the audio band (14-20kHz);
Compression from internal electrostatic forces due to voltage on layers: compression 10's of pico-meters; forces of 6.5N inside, 23.3N outside. Internal forces cancel due to each layer seeing two opposed forces.
Electrodynamic force due to current flowing inside the 'sheet' much less, ball-park 1.3 x 10^-5N.
Main mech resonance caused by 'squeeze' from outside layer. As force is always attractive, the vibration is at double signal frequency.
For whatever it is worth, but should be good for another 10k pages here. Am looking forward to the 1st guy who sees money in non-compressive capacitors ;-)
Jan
The measurements were done on a 4.7uF wound film xover cap with a laser vibro-meter.
My notes say:
Measured mechanical effects at the top of the audio band (14-20kHz);
Compression from internal electrostatic forces due to voltage on layers: compression 10's of pico-meters; forces of 6.5N inside, 23.3N outside. Internal forces cancel due to each layer seeing two opposed forces.
Electrodynamic force due to current flowing inside the 'sheet' much less, ball-park 1.3 x 10^-5N.
Main mech resonance caused by 'squeeze' from outside layer. As force is always attractive, the vibration is at double signal frequency.
For whatever it is worth, but should be good for another 10k pages here. Am looking forward to the 1st guy who sees money in non-compressive capacitors ;-)
Jan
Last edited:
But it has a nice high-end ring about it, no?
"Non-compromise design with non-compressive capacitors in all critical positions" .
Jan
I think it might have been SY who pointed out that some 'handmade' 'audiophile' capacitors were somewhat loosely wound (when compared to nasty horrible unmusical factory made caps). This might give rise to problems, which of course if audible will be construed as a 'night and day' improvement in sonics - given the cost of such caps.
It´s just about logic. If you use a premise it has to be correct for a correct conclusion, if you don´t know about the correctness of your premise .....
While I am at it. Anybody here ever listened to his amplifier heatsinks? Seriously.
Run your power amp into a dummy load, sweep the frequency through the audio band. At some frequency, often several, you can clearly here the vibrations of the heatsink fins as they get into resonance.
The excitation comes from the mechanical vibrations from the output power devices as they cycle through the current and dissipation variations.
One more cause for audible differences: heatsink resonances.
Jan
Run your power amp into a dummy load, sweep the frequency through the audio band. At some frequency, often several, you can clearly here the vibrations of the heatsink fins as they get into resonance.
The excitation comes from the mechanical vibrations from the output power devices as they cycle through the current and dissipation variations.
One more cause for audible differences: heatsink resonances.
Jan
It's still curious. Whenever some try to talk about his point of view on the audibility of something on this forum, he immediately receives a drop of insulting answers from the "Objectivists".
He is accused of selling snake oil, being hypnotized or dishonest, of to destroy everything science has brought us.
Yet no one is forced to follow others views and choices.
When we write "a slight colouration", this sect of "pure objectivists" quotes him by distorting his words, as if he had written "total destruction".
Apart from the fact that it is just stupid to apprehend the electro / acoustic and the hifi without listenings, (and they are most of the time "subjective", of course). As stupid that, for an optician, to develop lenses without looking at the results (quality of the bokeh, color rendition, progressivity of the sharpness etc.), I find that the sect of those pseudo objectivists is proving such a bad education, such a lack of respect for others, such aggressive attitude, that for nothing in the world, I would like to be a member of this clan.
When somebody assert he hear something, I just try to figure out if i can feel the same thing, and make my own opinion. I don't ask for juridic "evidence" and i think it is not so easy to fool me with words, a lot of snake oil sellers tried-it with no success.
I am really shocked by the way Mr. Marsh was treated here. He has, probably, made more measurements than most of us, here, and i doubt many are so well equipped with measuring instruments than him: it is obviously his passion. And, as far I can see, he never tried to sell anything.
it would be more simple if the things were black or white, in our universe, but, sadly, it is not the way it is.
He is accused of selling snake oil, being hypnotized or dishonest, of to destroy everything science has brought us.
Yet no one is forced to follow others views and choices.
When we write "a slight colouration", this sect of "pure objectivists" quotes him by distorting his words, as if he had written "total destruction".
Apart from the fact that it is just stupid to apprehend the electro / acoustic and the hifi without listenings, (and they are most of the time "subjective", of course). As stupid that, for an optician, to develop lenses without looking at the results (quality of the bokeh, color rendition, progressivity of the sharpness etc.), I find that the sect of those pseudo objectivists is proving such a bad education, such a lack of respect for others, such aggressive attitude, that for nothing in the world, I would like to be a member of this clan.
When somebody assert he hear something, I just try to figure out if i can feel the same thing, and make my own opinion. I don't ask for juridic "evidence" and i think it is not so easy to fool me with words, a lot of snake oil sellers tried-it with no success.
I am really shocked by the way Mr. Marsh was treated here. He has, probably, made more measurements than most of us, here, and i doubt many are so well equipped with measuring instruments than him: it is obviously his passion. And, as far I can see, he never tried to sell anything.
it would be more simple if the things were black or white, in our universe, but, sadly, it is not the way it is.
Last edited:
- Status
- Not open for further replies.