Hi Jan Didden
Idling car engine...?
Have you ever been onboard VLCC (Very Large Crude Oil Carrier), which has a big engine of about 30,000BHP? Sometimes, such a ship is poorly designed and resulted in terrible vibration on the bridge, where important electrical navigation equipment like radar, radio, sonar and many more are located. Even after a repairing, the vibration problem still remains to certain degrees.
For this reason and in case, we should require by rules that all navigation equipments are to be certified after having environment tests for the regulated vibrations (and temperature, humidity) before being installed onboard. Yes, the vibration tests with respect to the given criterion of frequency-range, displacement and acceleration amplitudes. Very essential!
By the way, all these test requirements are put on considering potential failures of mechanism of the equipment, not considering potential interruption of traffic of the current flow inside conductors (semiconductors). All my colleges, Scandinavian electrician, in our office look at me, huh?, whenever I ask them about the relation of the machanical vibration and the current flow interruption¡¦
Just a chap based on my profession, as you talked about the idling car... and as this thread moved to here, Everything Else...
JH
PS, I also respect Peter Daniel's works and I hope he will cool down a little bit on his good humor...
Idling car engine...?
Have you ever been onboard VLCC (Very Large Crude Oil Carrier), which has a big engine of about 30,000BHP? Sometimes, such a ship is poorly designed and resulted in terrible vibration on the bridge, where important electrical navigation equipment like radar, radio, sonar and many more are located. Even after a repairing, the vibration problem still remains to certain degrees.
For this reason and in case, we should require by rules that all navigation equipments are to be certified after having environment tests for the regulated vibrations (and temperature, humidity) before being installed onboard. Yes, the vibration tests with respect to the given criterion of frequency-range, displacement and acceleration amplitudes. Very essential!
By the way, all these test requirements are put on considering potential failures of mechanism of the equipment, not considering potential interruption of traffic of the current flow inside conductors (semiconductors). All my colleges, Scandinavian electrician, in our office look at me, huh?, whenever I ask them about the relation of the machanical vibration and the current flow interruption¡¦
Just a chap based on my profession, as you talked about the idling car... and as this thread moved to here, Everything Else...
JH
PS, I also respect Peter Daniel's works and I hope he will cool down a little bit on his good humor...
But of course it is. Has anyone ever heard a 'scientifically' designed amp which sounds not merely acceptable, but brilliant? The current 'science' guidelines produce pretty mundane sound and anything which sounds better is based on empirical principles rather than orthodox science. Examples in the world of amps are numerous. As audio fanatics, we have only one sensible guideline: to get closer to what our ears say is right. A bit of engineering know-how is absolutely essential to get a project to a working point, bit above that point lies a void of unexplored and unexplained in the textbooks, where only experience, far fetched theories and a good ear will help.
Of course, at this stage, the ones who can hear will never be able to reconcile their differences with the ones who can't. If i have to be honest, if i was half deaf, i'd be a bigger sceptic than... better not to mention names 🙂 The sceptic's position is so much easier after all. And so much more sensible. Plus a ton of 'evidence' to support it. However, i somehow don't feel jealous.
peter
Has anyone discussed the differences in parasitics introduced by the various insulator pads? I would think that this has the potential to alter sonics slightly.
Unscientific testing
How about all of you sceptical types trying the following experiment.
1. Take one of your analogue components (say a line stage or power amp) and stick a cushion under it.
2. Listen for 2 - 3 days to a range of music.
3. Remove cushion
4. Repeat (2).
5. Tell us if you hear a difference, if you do, try and measure it.
6. Report back
I get really fed up with these discussions, they never go anywhere and the resolving capability of most DIY'ers test gear is insufficient to resolve effects I know are there. If you can't hear it, don't worry, if you can, just deal with it (which is where the engineering comes in).
Minds and ears work best when open, but I will add that as an aerospace engineer the sensitivity of electronics to relatively small amounts of vibration is something that I've had to deal with regularly - RF PLL's are one of the worst in this regard, often being acutely sensitive to low levels of vibration, in a very obvious and measurable way.
Andy.
How about all of you sceptical types trying the following experiment.
1. Take one of your analogue components (say a line stage or power amp) and stick a cushion under it.
2. Listen for 2 - 3 days to a range of music.
3. Remove cushion
4. Repeat (2).
5. Tell us if you hear a difference, if you do, try and measure it.
6. Report back
I get really fed up with these discussions, they never go anywhere and the resolving capability of most DIY'ers test gear is insufficient to resolve effects I know are there. If you can't hear it, don't worry, if you can, just deal with it (which is where the engineering comes in).
Minds and ears work best when open, but I will add that as an aerospace engineer the sensitivity of electronics to relatively small amounts of vibration is something that I've had to deal with regularly - RF PLL's are one of the worst in this regard, often being acutely sensitive to low levels of vibration, in a very obvious and measurable way.
Andy.
analog_sa said:
Analog,
I was very unclear, I apologize. What I meant to say that the METHOD to get an answer is un-scientifically. I strongly believe that the ONLY way to make meaningfull progress about anything is the scientific method, ie to methodologically analyse the situation, try to find out what the problem is and solve it. In this case (and I by no means want to single out Peter) the step from realising that different pads transmit mechanical vibrations differently, to the conclusion that that gives either airy or dull sound is totally unscientific. First, prove that the vibrations DO change the sound, which I am not sure off. THEN see if you can find out HOW it changes the sound (more harmonics? only change in freq response?). And your examples are very interesting, and surely we don't want the ship's arials to fall off because of vibration, but I don't think it is relevant to the problem at hand.
Jan Didden
Jan
Whilst I agree partly with the above, it comes first from the assumption that the proof comes from measurement.
Does the fact that one can hear it not count?
Surely that HAS to be a starting point, the analysis / engineering follows from that. The problem is what happens if you cannot resolve the measurement, with the apparatus at hand?
This is a DIY Audio forum and not everyone is blessed with owning an AP, or a sufficiently good FFT spectrum analyser. What are these people to do, ignore the evidence of their ears, convince themselves that what they hear is an illusion, or make their music less enjoyable simply because they can't prove to others what they hear?
If I find something sounds better, I'm hardly going to ignore that evidence when designing something new, simply because I cannot prove the existence of an effect.
None of the above BTW is an attempt to argue AGAINST measurement, but simply that in my experience the ability to resolve the effects is a huge challenge to a DIY'er and that if we take this view we will drive away a healthy active community with vested interests.
We should rememeber that the goal is the enjoyment of music, not measurement; how it sounds is ALL that ultimately matters.
For those that like to prove / understand things better let them, but do not put down the views of others because they do not, or cannot provide 'proof'.
There is plenty of evidence in the real world of manufacturers going to great lengths to deal with vibration in audio electronics, and I doubt they do this just for the fun of it.
Andy.
Whilst I agree partly with the above, it comes first from the assumption that the proof comes from measurement.
Does the fact that one can hear it not count?
Surely that HAS to be a starting point, the analysis / engineering follows from that. The problem is what happens if you cannot resolve the measurement, with the apparatus at hand?
This is a DIY Audio forum and not everyone is blessed with owning an AP, or a sufficiently good FFT spectrum analyser. What are these people to do, ignore the evidence of their ears, convince themselves that what they hear is an illusion, or make their music less enjoyable simply because they can't prove to others what they hear?
If I find something sounds better, I'm hardly going to ignore that evidence when designing something new, simply because I cannot prove the existence of an effect.
None of the above BTW is an attempt to argue AGAINST measurement, but simply that in my experience the ability to resolve the effects is a huge challenge to a DIY'er and that if we take this view we will drive away a healthy active community with vested interests.
We should rememeber that the goal is the enjoyment of music, not measurement; how it sounds is ALL that ultimately matters.
For those that like to prove / understand things better let them, but do not put down the views of others because they do not, or cannot provide 'proof'.
There is plenty of evidence in the real world of manufacturers going to great lengths to deal with vibration in audio electronics, and I doubt they do this just for the fun of it.
Andy.
Re: Jan
OK Andy, I fully understand your point. But what is the alternative? Everybody rushes out to replace the silicone pads under their TO220's because that gets rid of the dull sound? I don't expect everybody to start frantically measuring this. But I would hope that we use more the intellectual capabilities we have been given freely. Or maybe I should take the stand, hey, they're just having fun, what the heck? Maybe that's my problem, I'm treating this all too serious.
Jan Didden
ALW said:
OK Andy, I fully understand your point. But what is the alternative? Everybody rushes out to replace the silicone pads under their TO220's because that gets rid of the dull sound? I don't expect everybody to start frantically measuring this. But I would hope that we use more the intellectual capabilities we have been given freely. Or maybe I should take the stand, hey, they're just having fun, what the heck? Maybe that's my problem, I'm treating this all too serious.
Jan Didden
It think that others should try them and report back, those of us with the right kit, may even like to take some measurements.
The bit I do have a problem with is the pseudo-science that Peter offers as explanation, he should simply state that he preferred the sound of the pads in his amp, and tell us what he heard.
FWIW, there's vibration and of course simple electrical issues like capacitance to factor in - these pads are much thicker than standard mica or SIL-pads, if I'm not mistaken - this is just as likely to affect the sound and be measurable.
The thermal performance will be different too, with different mechanical characteristics at different temps, vis-a-vis SIL-pads.
Andy.
Andy:
>there's vibration and simple electrical issues like capacitance - these pads are much thicker than standard mica or SIL-pads - this is just as likely to affect the sound and be measurable.<
That was my reaction, too. I would immediately suspect varying degrees of capacitive coupling to ground (or whatever voltage potential the chassis is at), and whatever effect that coupling may have on the stability and high-frequency behaviour of the circuit in question.
Incidentally, the initial production versions of the GainCard had a rather longer signal path that what it is now. One day, Kimura and Teramura mentioned that they had shortened the physical length of the feedback loop (I believe that they soldered the feedback resistor directly to the IC legs, as close up to the IC body as possible). They reported significantly better sound as a result. Now a physically short feedback loop is something that we (Petr Mares and myself) had already been doing for years, and drawing on my own experience, I asked Kimura if the IC's operating temperature decreased when the feedback loop was shortened. He replied in the affirmative.
My conclusion was and is that the original version of the Gaincard circuit had been suffering from low-level oscillation at high frequencies. Physically shortening the feedback loop and reducing the associated parasitics stabilized the amplifier, and the sound improved as a result.
hth, jonathan carr
PS. Andy, did you receive my reply with the additional distortion data?
>there's vibration and simple electrical issues like capacitance - these pads are much thicker than standard mica or SIL-pads - this is just as likely to affect the sound and be measurable.<
That was my reaction, too. I would immediately suspect varying degrees of capacitive coupling to ground (or whatever voltage potential the chassis is at), and whatever effect that coupling may have on the stability and high-frequency behaviour of the circuit in question.
Incidentally, the initial production versions of the GainCard had a rather longer signal path that what it is now. One day, Kimura and Teramura mentioned that they had shortened the physical length of the feedback loop (I believe that they soldered the feedback resistor directly to the IC legs, as close up to the IC body as possible). They reported significantly better sound as a result. Now a physically short feedback loop is something that we (Petr Mares and myself) had already been doing for years, and drawing on my own experience, I asked Kimura if the IC's operating temperature decreased when the feedback loop was shortened. He replied in the affirmative.
My conclusion was and is that the original version of the Gaincard circuit had been suffering from low-level oscillation at high frequencies. Physically shortening the feedback loop and reducing the associated parasitics stabilized the amplifier, and the sound improved as a result.
hth, jonathan carr
PS. Andy, did you receive my reply with the additional distortion data?
Jan
All the years i've spent messing with audio i've heard little evidence that my ears are very sensitive to either frequency response anomalies or excessive thd. Yes, some people obsess about riaa accuracy, but i am more likely to hear a different type of cap in riaa than a db or two out of perfect. Same with thd; in many respects SET amps are far from perfect sonically, but perceived distortion is not one of their problems. Measurements may be invaluable in designing better PS regulators and you may even see some correlation between perceived and measured performance, but to expect that vibration control of a semiconductor device would result any measurable difference in thd and freq linearity is very naive. Surely all these effects are way below the threshold of what is commonly measurable, as to why we hear them, i am as stumped as everyone else, but we do.
In my mind, the highly non-linear way we hear and the very sophisticated (and mysterious) signal processing which follows the ears are responsible for a perceived sound very different from what one's common sense leads to expect. To my ears, the effects which cannot commonly be measured, such as these caused by wire, mechanical construction, dielectrics, vibration control, power supply etc have more influence on the final perception of musicality and naturalness than any combination of 'objective' parameters. Or in short: circuit topology may be responsible for 35-40% of the final sound, the rest is the result of empirical observations and of course science, but applied in a very unscientific way.
peter
All the years i've spent messing with audio i've heard little evidence that my ears are very sensitive to either frequency response anomalies or excessive thd. Yes, some people obsess about riaa accuracy, but i am more likely to hear a different type of cap in riaa than a db or two out of perfect. Same with thd; in many respects SET amps are far from perfect sonically, but perceived distortion is not one of their problems. Measurements may be invaluable in designing better PS regulators and you may even see some correlation between perceived and measured performance, but to expect that vibration control of a semiconductor device would result any measurable difference in thd and freq linearity is very naive. Surely all these effects are way below the threshold of what is commonly measurable, as to why we hear them, i am as stumped as everyone else, but we do.
In my mind, the highly non-linear way we hear and the very sophisticated (and mysterious) signal processing which follows the ears are responsible for a perceived sound very different from what one's common sense leads to expect. To my ears, the effects which cannot commonly be measured, such as these caused by wire, mechanical construction, dielectrics, vibration control, power supply etc have more influence on the final perception of musicality and naturalness than any combination of 'objective' parameters. Or in short: circuit topology may be responsible for 35-40% of the final sound, the rest is the result of empirical observations and of course science, but applied in a very unscientific way.
peter
That is though the basic premise that I have a problem with.
1. That we NEED to prove it
2. That you CAN prove it.
As I've said many times before, it's not possible to conduct a listening test (no matter how scientific one tries to be) that can PROVE anything - proof requires hard factual results, determined by measurable objective criteria.
Listening though is a subjective assessment with no known measurable correlation and can therefore never provide proof. Since the basic premise being discussed stems from subjective assessment, we have a problem.
One can find correlation between sound and measurement, but you can never absolutely determine the one from the other.
Peter has dug himself a hole, but is wise not to engage in a proof, simply because it cannot be done.
No-one has ever written down a scientific procedure that can provide such proof, despite my asking several forum contributors on many occasions. I'm happy for someone to do so, if they think proof, as opposed to evidence, can be the result.
Andy
Hi,
From my POV, in this case it should be possible to measure the difference given the right equipment.
The reason is that not only the mechanical damping is altered but also the amount of stray capacitance and quite likely the operating temperature of the chip(s).
Maybe a null test can bring it up also...assuming one accepts that as sufficient proof...for it seems that those wanting proof always find themselves ways to disprove.
Cheers,😉
From my POV, in this case it should be possible to measure the difference given the right equipment.
The reason is that not only the mechanical damping is altered but also the amount of stray capacitance and quite likely the operating temperature of the chip(s).
Maybe a null test can bring it up also...assuming one accepts that as sufficient proof...for it seems that those wanting proof always find themselves ways to disprove.
Cheers,😉
ALW said:
Let's me dress your first assertion first since your reply is for the most part focusing on the 2nd half.
We are here for the pursuit of better sound (Peter's venture not withstanding). And if "better sound" doesn't need proving, how confusing do you think it is?
One could come here and assert all sorts of crazy things and what would a newbie like myself who has no qualification in audio / electric engineering and who doesn't understand squat about electric engineering, as some of the forum members had asserted before do?
What would be there to prevent or at least keep in check people from making questionable / false claims for purposes other than DIY audio (Peter, in case you jump on this, I am not implying that you are one of them)?
As to the science to prove it. I am not sure 1) any proof is absolute. and 2) you need objective measurements to prove it.
In this world, no thing is absolute (other than the statement itself, 🙂). what we believe to be true is likely to turn out to be false in the future. and there are enough examples of that so let's move onto the 2nd point.
I don't think our understanding of human hearing and present state of engineering will allow us to measure everything there is in human hearing. and I am not sure if we will ever get there.
so it is paramount that one accepts the limitation of our measurement systems and prepares oneself for the ultimate measurement system: our ears.
The use of humans as measurement itself introduces another set of challenges. The least of which is our subjectivity. Through careful design and experiment, however, one can hope, but not be guarantteed, to arrive at an objective (in the sense of it coming from a large sample and reflecting the view of the population it represents) view on a rather subjective matter.
One such test is the Tube vs. Transistor test article published or linked at Dr. Leach's site.
and it is my view that doing a similar test (maybe not to that kind of extent) will be extremely helpful to solidify Peter's claims on a series of matters and restore his credibility in the community.
But I personally find puzzling the inconsistency or sharp contrast between Peter's insistence on the pad-sound and his going to length trying to avoid a test, between his elaborate and creative experiments on various components in his gainclone amp and his seemingly challenged state of affairs on methdologies one may employ to affirm the pad-sound.
But, what does a fool like me know about the mystic land called high-end audio? 🙂
ALW said:
Andy, I am happy to provide one, if you are OK with it. I am not sure how scientific it is, tho.
How about getting a few test subjects. Divide them into three groups. Those who believe in pad sound, whose who don't, and those who don't know about it.
Provide two identical gaincard amps, one with a silpad (amp S) and one with an AO pad (amp AO). do the usually trick of volume adjusting them, etc.
Conduct a series of double blind A vs. B listening tests, and ask the subjects two questions:
1) if A is different from B;
2) if A is preferred over B.
A / B can be either amp S, amp AO, or both. So the possible combinations are
amp S, amp S
amp S, amp AO
amp AO, amp S
amp AO, amp AO.
at alpha of 95%, run a hypothesise that amp S sounds the same as amp AO. (t-test I believe).
at the same confidence level, run another hypothesis that amp S is preferred over amp AO.
it would be interesting to know how well doug blackburn will do in such a test, 🙂
Millwood
What time interval do you propose for your tests and evaluations?
The ear can only detect certain fundamantal changes during a relatively short assessment time (read: minutes, hours).
During this time one can make simple assesments related to amplitude and frequency balance. This is the problem with DBT - short time spans, matched amplitudes etc. reduce the ability to determine any difference at all. It's a null result, not a proof.
The assessment of the underlying improvement in the music (totally unrelated to both the above criteria) often only comes after several days listening, or at least a good few hours. This is a critical point - frequency response errors, changes in amplitude have NO EFFECT whatsoever on the fundamentals of the music, providing the devices are operating within their envelopes, and the changes are not so extreme as to cause other ill-effects.
This is what makes many people think that speakers are the worst part in the chain, as they have the grossest reponse / amplitude errors. They are most important to the sound least important to the music.
Quick A/B's do not work, they fail to take into account the way we hear, the processing of which occurs in the brain.
I think Jonathan Carr's method, proposed previously, of making externally identical amplifiers labelled A / B or C, with the salient details identified internally is a better method.
One has to ensure that the insides cannot be seen / viewed without obvious evidence you then simply pass these amps onto a number of individuals who report their experience / preference over a long time period. The data / listening notes are then analysed subsequently.
How many times have you changed something with the immediate result that you think it's better, only to find, several days later that it isn't? This is a common theme amongst those of us actually doing this stuff.
I've done a lot of design work with remote partners, where improvements have been made and both of us have reported identical results, sonically, and this has often been with people I would view as having daimetrically opposed views to my own, with different systems, musical tastes etc.
I strongly believe that better is better for most people and this has been a most surprising finding for me, the difference in opinions solely comes down to the actual location you are along the audio path to nirvana - I may not like your system, you may hate mine, but an improvement to a common area is likely to be the same to both of us.
Andy.
What time interval do you propose for your tests and evaluations?
The ear can only detect certain fundamantal changes during a relatively short assessment time (read: minutes, hours).
During this time one can make simple assesments related to amplitude and frequency balance. This is the problem with DBT - short time spans, matched amplitudes etc. reduce the ability to determine any difference at all. It's a null result, not a proof.
The assessment of the underlying improvement in the music (totally unrelated to both the above criteria) often only comes after several days listening, or at least a good few hours. This is a critical point - frequency response errors, changes in amplitude have NO EFFECT whatsoever on the fundamentals of the music, providing the devices are operating within their envelopes, and the changes are not so extreme as to cause other ill-effects.
This is what makes many people think that speakers are the worst part in the chain, as they have the grossest reponse / amplitude errors. They are most important to the sound least important to the music.
Quick A/B's do not work, they fail to take into account the way we hear, the processing of which occurs in the brain.
I think Jonathan Carr's method, proposed previously, of making externally identical amplifiers labelled A / B or C, with the salient details identified internally is a better method.
One has to ensure that the insides cannot be seen / viewed without obvious evidence you then simply pass these amps onto a number of individuals who report their experience / preference over a long time period. The data / listening notes are then analysed subsequently.
How many times have you changed something with the immediate result that you think it's better, only to find, several days later that it isn't? This is a common theme amongst those of us actually doing this stuff.
I've done a lot of design work with remote partners, where improvements have been made and both of us have reported identical results, sonically, and this has often been with people I would view as having daimetrically opposed views to my own, with different systems, musical tastes etc.
I strongly believe that better is better for most people and this has been a most surprising finding for me, the difference in opinions solely comes down to the actual location you are along the audio path to nirvana - I may not like your system, you may hate mine, but an improvement to a common area is likely to be the same to both of us.
Andy.
Quite the opposite. Peter is claiming to have possibly found an interesting phenomenon. Putting aside the notions of analogy, there's not much in the way of a clear mechanism in the electronics to explain this- unless Audio Freak's hypothesis is correct. Either way, there's potentially something important here, and those of us who would love to see the state of the art advanced, rather than just speculated about, are trying to figure out a way to pin this down.
Now, measurement is a fine thing IF you know what you're looking for. And IF you know you're not chasing a chimera. So the first thing that has to be done is to take the instrument that is giving the "funny" result (in this case, Peter's perceptual system) and run the experiment. It's possible that there's a real phenomenon here. It's also possible that Peter is falling into the normal human trap of bias and expectation. It's improper to assume one or the other in the absence of evidence. So the way to cut this problem in half is by LISTENING, not measuring.
And fortunately, through more than a century of sensory research, the methods exist to use the human faculty of listening to determine what's going on. Since Peter, like most of us, doesn't have much experience with sensory testing, my suggestion has mutated to something about which he (and apparently others) feel just as confident, but less emotional.
So, let's give the rhetoric a rest and start with some baby steps.
Sy,
I have no problem with much of what you say and believe that Peters analysis of the cause / effect may be wrong, in this case. Not that there isn't a difference, but simply that his theory may not be the reason for it.
The above though, I do have a problem with, for the reasons stated above, most A/B or DBT's are fundamentally flawed, but I've not personally seen any evidence that these issues have been dealt with.
I'm happy to be shown evidence to the contrary though.
The tests proposed thus far are flawed, can you point me towards yours?
Andy.
Edit: just found relevant thread - will read first!
Re: Re: Jan
This shouldn't be the case, as one other member mentioned that he preffered the sound of silicone pads and not AO.
I never stated that one is better than the other, or tried to seriously explain the process behind it. Whatever I did was only my guess, I stressed it few times and I always claimed that this is only my prefference in a given setup. Check the posts.
janneman said:
This shouldn't be the case, as one other member mentioned that he preffered the sound of silicone pads and not AO.
ALW said:
I never stated that one is better than the other, or tried to seriously explain the process behind it. Whatever I did was only my guess, I stressed it few times and I always claimed that this is only my prefference in a given setup. Check the posts.
Re: Re: Jan
Millwood,
You don't give up, do you? If you built the test circuit for the pads, I will gladly perform tests. I can also provide any assistance you might need. I'm sure SY will too. I believe it was you complaining about nobody's testing it, so don't blame it on me. So this is my position on that and stop your constant rant about me not being eager to do it. I simply have other priorities and not enough time.
Now tell me something, why do you need that proof? Will it improve your hearing?
millwood said:
Millwood,
You don't give up, do you? If you built the test circuit for the pads, I will gladly perform tests. I can also provide any assistance you might need. I'm sure SY will too. I believe it was you complaining about nobody's testing it, so don't blame it on me. So this is my position on that and stop your constant rant about me not being eager to do it. I simply have other priorities and not enough time.
Now tell me something, why do you need that proof? Will it improve your hearing?
A superb philosophical question. It won't improve anyone's hearing, but it lets the engineering-minded among us know what's worth chasing.
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