Why Some Audiophiles Fear Measurements

[Orb]

You are correct that context is very important, but I maintain that specs are even more important. I'll try to break it out logically:

10 percent IMD might be benign on two frequencies an octave apart, such as a solo flute and it's prominent second harmonic. But on a cymbal crash the low-mid tones added by the IMD will be obvious and irritating to hear. IMD on cymbals and tambourines and spoken voice is especially nasty because it adds low frequencies that are not normally present with those sources. So the obvious conclusion when buying a new amp etc is to look at the specs, and disregard anything with unusually high levels of IMD. Yes, it may not be audible on all sources, but it will certainly be audible on some sources. So it's definitely not a useless spec.

Although as I pointed out the very good products have 0.1% complex IM distortion (this is way beyond just two tones/frequencies and shows how current measurements are rather restrictive due to having a specific task) and no where like 10% as you may suggest (with the good products and not bad design-implemented), please look at the very last quote where Nelson stated it is quite possible for complex IM to be 0.1%IMD for both negative feedback and zero feedback.
Bear in mind distortion tests from reviews are over the complete frequency range including those I showed for the NAD and ARC, so thnis covers voices and cymbals-etc that you mention.

Anyway this ignores the original discussion point where I raised a cheap negative feedback preamp by NAD that is pretty well designed and also a tube preamp with zero feedback.
Now if you ever listen to a reference tube preamp I think anyone will have a hard time to say that it and a cheap negative feedback preamp sound exactly the same and a lot of those can come down to the descriptions such as resolution, transparency, soundstaging, imaging shown in Jeff's article.
Also consider I showed two such products with negligible measurements.
Distortion was lower than 0.001%, which means it falls into Nelson's category for negligible complex IMD.

The same goes for THD and frequency response. As Ponk said to Mike a few posts back, "So these amps will make warm, sweet speakers with a bass-extension emulating low midrange hump and a harshness-reducing upper midrange dip sound wonderful, then they'll turn right around, without any eq, or any other changes in the system and make dry, treble-forward speakers with a lean bass sound wonderful too?" A coloration that sounds good on some sources may sound bad on others, and have little affect on yet others.

Again I understand that but this also ignores my point where I show two totally different products that measure negligible differences for FR and THD (which also reflects negligible IM).

As soon as you show what else there is - being excruciatingly specific! - I'll be glad to update my opinion.

But it is YOU who is stating your 4 parameters as fact for what we hear in audio reproduction
So the onus is also on you, but at least I went as far as finding two products that subjectively are different and also had measurements showing negligible differences, this becomes more interestingly because they are vastly different designs and one is a tube design.
You mentioned a few times in other threads:

There are four parameters that affect audio reproduction: Frequency response, Distortion, Noise, Time-based errors

However you have not gone into excruciatingly specific detail by showing the correlation between these parameters vs specific perception descriptions which are easy to classify as Jeff has done.

It sounds like you're talking about psychoacoustics, which is unrelated to gear parameters. Further, and I'm sure I've said it a dozen times this past week alone, what you hear one moment may not be what you hear the next. You could easily like the sound of some recording on someone's system today, but hate it tomorrow. This is inside your head and has nothing to do with what happens inside the gear. So it's not proper to bring up "how we hear" into this discussion. I'm talking about gear parameters, not the foibles of human hearing.

I have not even gone into psychoacoustics, I am the only one actually presenting hard measurements with their point Ethan that are also backed up by study done by Nelson Pass
If your talking about that you need to go the next step otherwise your only presenting a hypothesis and that step involves blind listening studies or initially correlating your 4 parameters to specific perceptions and also measurements then we are using different words.
Because that is not psychoacoustics its validation process towards your hypothesis.

I never took it as an insult, and I call them my four parameters too. But to all who believe there is more to assessing the fidelity of audio gear than these four parameters, please tell us specifically what more there is using quantifiable objective terms. "Resolution, transparency, soundstaging" are all useless because they mean different things to different people, and they also have no metric.

Glad of that and you are pretty easy to debate with (even if I do disagree at times ) as I never seen you get angry but felt I should clarify the wording as it can come across a bit tough on forum when in reality I am as gentle as a baby lamb awww
And yeah it is a challenge to take descriptive words relating to perception, thats why you need to be careful on choosing both the words and the listener and also use multiple reviews and measurements they have done, but the real study should be a well designed blind study taking all of this into a test protocol (training on the use of words to hearing and structured framework).
As I say until you go into excrutiating detail (sorry for stealing your words ) yourself then all you have is a high level concept but some areas that are known but only work in limited ways.

This is why IMO there will never be a satisfactory resolution to such debates (I mean beyond just you and me), because neither side can or is willing (either due to scope definition or resource or time-effort,etc) to take the necessary steps to move from hypothesis to detailed fact with correlation.
But one thing worked out, I finally broke down to your post into split quotes, so thats something

Cheers
Orb

 

[kareface]

Dear Kareface: Yes you are right. Things are that is not easy for me to explain in precise way what I have on mind because my English vocabulary is limited and not good as my native language that's the Spanish.

Yes, I agree too that part by part could be easy to understand complex " relationships ". I'm under " training " here and ready to learn.

Regards and enjoy the music,
Raul.

No problem, I figured that ESL was playing a factor here. It was just a few little things like the excessive use of quotes that threw me off a little. I'm glad to see there are people who enjoy audio who haven't become dogmatic about their beliefs. I've taken away a few good pieces of information just from the last few days responding to this thread.

 

[Orb]

I think Ethan acknowledged that it was a simplistic method. The point is in the contexts of his comment he wasn't off base. I think the primary point of of debate is that he's excluding many other factors that will have an impact on reproduction, and people are repeatedly trying to point out the fact that he left them out. He knows other factors were left out, and he's arguing that in the context of his post the comments are accurate. So we get this cycle of people pointing out it doesn't include y factor, and him saying that y factor wasn't part of the original equation, repeat for z. In the narrow context of the original comment his numbers are largely valid. Does that necessary reflect what you hear? It's completely situational, if you have a clean enough system the room will be the all encompassing factor. If you have some glaring flaw in your system, it'll be reflected in the reproduction and might be more audible than the linear FR distortion from nodes. I still believe that using real world scenarios over 50% of the influence is acoustic. Tonality varies widely with the environment, many rooms are under treated and produce audible noise and nodes can be quite influential creating huge peaks that mask higher frequencies or drop frequencies out all together. If you think about the impact just poorly placed speakers have on reproduction you'll understand how influential the room is. Even if the speakers are placed so they image well, if they are positioned wrong relative to the environment they can sound terrible.

Maybe we are focusing on different aspects of what Ethan is mentioning - I appreciate he is responding to many topics in this thread.
TBH I feel Ethan suggests nothing is left out or I could be misunderstanding.
This is the thread topic myself and Ethan have been discussing but I appreciate this does not reflect some of the other discussions with him:

I don't know about meaningless, because frequency response is the best measure of tonal color. But I agree it's not the only thing. There are four parameters that affect audio reproduction:

Frequency response
Distortion
Noise
Time-based errors
Of course, there are subsets, such as hum and buzz and LP crackles under noise. I explain these four parameters more fully here:

And looking back you can see how this fits into the context of our debate.
Sorry if your post did not also mean to include our set of discussions.
Cheers
Orb

 

[FrantzM]

raul

Let me get it right. a few questions:

Is there an hierarchy in Audio reproduction ?
If NO... End of the discussion...

If Yes,
what do you think, accounts for most of what we hear from our system?
Whatever it is, what percentage of a finite fund would you allocate for it?

At this point in time to me it is Room-Speakers at 80% ... The rest will come...Three years ago, I would have told you that I would have left my reference system alone and just get better, much better speakers, the former personal reference speakers were very good and giant-killers in their own rights (MG 20.1) and invest a little more in Room Treatment. I had already invested quite a bit (an euphemism) in what I continue to this day to consider as superlative but unfortunately pricey Electronics, serious front end (both analog and Digital) and yes, people in cables of the most exotic and expensive type ... Then I believed that cables made a "huge" difference which I wasn't able to perceive once the knowledge of which cable in use, was removed... I was younger then, I have matured since

 

[The Smokester]

...What I'm not convinced in deep is about those %%% like the one you posted: " well above 80% of the total budget becasue they account for that percentage "...

Most people are considering this to be the relative contribution of the various components to the undesirable deviation from ideal system performance. It is not meant to apportion cost. You spend whatever is necessary to align all the components in quality with respect to this problem. There may be more problems and you would also try to resolve them in order of their contribution. Go after the worst ones first. To do this requires measurement, listening and experience.

 

[terryj]

I had already invested quite a bit (an euphemism) in what I continue to this day to consider as superlative but unfortunately pricey Electronics, serious front end (both analog and Digital) and yes, people in cables of the most exotic and expensive type ... Then I believed that cables made a "huge" difference which I wasn't able to perceive once the knowledge of which cable in use, was removed... I was younger then, I have matured since

Hi frantz, I'm pretty sure this will not be taken the wrong way (well hopeful at least) but this part got me wondering.

I am presuming a bit here, I assume at that time you were as active a participant on forums as now??

If so, this was what I wondered.

'Back then', what or how did YOU perceive the arguments from the objectivists?? (such a divisive word, as is subjectivist)

Did you dismiss them out of hand? What sort of arguments against their case did you either use or felt were applicable? Which of their arguments at the time got you thinking.

Did you take it personally, some sort of affront?

And now, from your 'new' perspective, having been on both sides of the debate, what would be the most effective way for a person to resolve these questions. There have been some who have done a dbt, yet quite quickly dismiss those results as a flaw in the procedure. Do you have any thoughts on how best to resolve those problems? Why is it that you, after having done something in this area, did not revert to the previous way of thinking?? Is that a purely personal thing I wonder, some sort of insight into our differing take on things....

 

[FrantzM]

Hi frantz, I'm pretty sure this will not be taken the wrong way (well hopeful at least) but this part got me wondering.

I am presuming a bit here, I assume at that time you were as active a participant on forums as now??

If so, this was what I wondered.

'Back then', what or how did YOU perceive the arguments from the objectivists?? (such a divisive word, as is subjectivist)

Did you dismiss them out of hand? What sort of arguments against their case did you either use or felt were applicable? Which of their arguments at the time got you thinking.

Did you take it personally, some sort of affront?

And now, from your 'new' perspective, having been on both sides of the debate, what would be the most effective way for a person to resolve these questions. There have been some who have done a dbt, yet quite quickly dismiss those results as a flaw in the procedure. Do you have any thoughts on how best to resolve those problems? Why is it that you, after having done something in this area, did not revert to the previous way of thinking?? Is that a purely personal thing I wonder, some sort of insight into our differing take on things....

Terryj

I have been participating in forums since 2003. I started posting actively in AVS. My views then were Audiophile Othodoxy. Cables would make a huge difference being one that I adhered to. Even then I had doubt about several tweaks finding these a waste of time and money. I was skeptical of several components whose pseudo-science I could easily debunk. To wit , the Active Electrical shield or Harmonix Kombats or Shakti stones or Qunatum Tunneling...,they could not make sense to me as to their rationale for effectiveness nor could I hear ANY differences when I tried some of these... I am by training an engineer and love science. TO me the Scientific Method has proven its worth throughout the years ... So Science should explain s what we hear.
On cables I put aside my engineer hat, since I could hear differences or so I thought. Those who would doubt the value of cables in a system were to me people who had never experienced what a cable would do in a system because in my then view, their system lacked "resolution". They were brushed of. Oh! I read about the Randi challenge and found that a little over the top so much back and forth there were ... So Cable made huge differences.

Then came an interesting in which a fellow WBF forum member participated. His system doesn't lack resolution by any stretch nor his understanding of great components even less his ears. He wasn't able to discern between his cables and some pretty basic cables.. I was a perplexed and conducted my own... Well I wasn't able either. I could not discern between 6 AWG copper cables and a very, very , very, expensive cable... Later the same month I conducted under similar conditions (nothing scientific, no DBT but knowledge of what was playing was removed) I tried the same thing with Digital front end with some modicum of rigo, RAT Shack SPL meter was used, to try the same experience with front ends .. I could really easily discern between a good CD player and Burmester DAC and Transport, almost consistently .. that wasn't anything that could be published even on a blog but it opened my eyes on the basics of sighted bias .. pun intended.
I began paying attention to how our mind cloud or evaluation. Not that I did not know it but I did believe that we, audiophiles, may have special abilities. I also quickly add that I continue to believe in what some call eduction and I do call "Training" . To me a listener can be trained to hear better or to see better. to discern differences that would leave the un-educated flat. I was a photographer back in the days .. I was interested int he Zone System and began to pay attention to lights variation and to translate it in shades .... So there I began to look at things differently, I began to open my mind to the humbling fact that our ears are not very reliable. We can be trained but removing most biases is difficult. It is almost humiliating but in the end liberating. Our senses are easily fooled.. That much I know and we actually all know it but there is a fear to admit it IMHO. It is as I said humbling ubt in some instances humiliating. It brings us to a "normal" level. The only thing we may have as an advantage is the Audiophile education, the training which allows us to pay attention so as to discern more of the differences else, physiologically we are even at a disadvantage as we age ... I remember that in my youth I could hear 20 Khz .. easy and piercingly so. Now despite my very healthy (or so says my audiologist) and above average hearing acuity, I can barely make it to 18 KHz, actually 17.8KHz.
That has made me be more realistic and open my whole mind to the Marketing and at the end profit aspect of High End Audio. The manufacturers are in it to make a buck or two or many. If they can play with our mind .. The more they will sell .. So the emphasis on an above science stance many of the companies take or of special research or of the inability of science to explain music or the Art of Music... While their stated goal goal is not to MAKE music but to REPRODUCE it as it is in the medium ... I began casting a suspicious eye and mind and attitude to the mega-priced components the 30K cables , the 100K amps and preamps and the half million dollars speakers. i also began to look at the price of upgrades .. sometimes a sizable fraction of the original price for few, subtle changes .. Of course Subjectivity weighs in and these changes to the fans are HUGE .. I remember being almost outraged by Wilson Audio charging $35K to upgrade the MAXX which when introduced was around $35K.
I also began quietly to see how the minds of audiophile was getting trained to accept the notion of "Price Class" .. You now the huge pile of Bovine Manure that a 10 K components cannot be better than a 100K one... (For Those in Tubes an honest and long audition of the ASL Hurricanes would dispell that notion in a hurry by experiencing how less than $5000 monoblocks can beat the pants of most tubes amps out there, but I digress..) ..

In the end I am most satisfied. I know now what NOT TO DO. I know now that I will focus on the best room I can build , drop in the best speakers my funds allow.The search is going to be extensive but I think I have my mind on two, very different speakers, both of distinction. Both not very well known... I will use at least 3 DIY subs, one of the area where DIY routinely outperforms commercial. The source shall be Digital PC-based with most likely a Professional-sourced DAC (Did someone say from Switzerland??? ). For fun I may get an analog front-end since I have been seeing R2R at more than decent price on e-bay and the likes . Electronics will likely be between Burmester and Spectral depending on funds availability .. likely none of the top components either produce, Cables shall be heavy gauge Copper (64 or 6 AWG). I will use a Double conversion UPS and this system may not change for a good while .... There is so much music to listen to an so little time

TO BE ON TOPICS ..

I am not entirely what now is termed an obectivist. I do not believe that measurements as they are taken right now tell the whole story. I believe that measurements may eventually tell most if not the whole story but we are far from that. I believe in long term audition and I believe in a mixture of following the measurements and long term audition if possible. I am by no means afraid of measurements.

 

[The Smokester]

The dB terms are derived from the absolute levels in the equations. The derivation is straight-forward but tedious. In the limit, of course there is no IMD if there's no HD, so the absolute value is zero and relative terms are meaningless. That would mean it is a totally linear system. However, if there is any nonlinearity (and there is always some in a real system), then the IMD tracks the HD at a somewhat higher level given by the equations.

Another way to think of it is that as the HD terms go to (-)infinity (in dB) anything added to that is still (-)infinity.

L'Hopital is still with us...

HTH - Don

Thanks for the correction, Don. I neglected to account for the units: The logarithm of the ratio of a difference.

 

[microstrip]

T I am by no means afraid of measurements.

But you should.

Measurements can be seen from two perspectives - something you use to during the development of an audio product, helping you to reach your target; or as an indicator of the quality the finished product. For this last application you must have a set of fixed rules and values validated and followed by the community. Otherwise you risk just considering the measurements and experiments that support your subjective views - then OK, you should not be affraid of them.

 

[Ethan Winer]

"well above 80% of the total budget becasue they account for that percentage".

It was already explained that percentage importance is not related to percentage of budget.

why the source can't be that 50% or even more?

It was already explained that the source music is outside of the reproduction path, and thus has nothing to do with "gear fidelity" which is what this thread is about.

Not to editorialize too much, but it's a waste of time for everyone when the same points have to be made repeatedly.

--Ethan

 

[Randy Bessinger]

Terryj

I have been participating in forums since 2003. I started posting actively in AVS. My views then were Audiophile Othodoxy. Cables would make a huge difference being one that I adhered to. Even then I had doubt about several tweaks finding these a waste of time and money. I was skeptical of several components whose pseudo-science I could easily debunk. To wit , the Active Electrical shield or Harmonix Kombats or Shakti stones or Qunatum Tunneling...,they could not make sense to me as to their rationale for effectiveness nor could I hear ANY differences when I tried some of these... I am by training an engineer and love science. TO me the Scientific Method has proven its worth throughout the years ... So Science should explain s what we hear.
On cables I put aside my engineer hat, since I could hear differences or so I thought. Those who would doubt the value of cables in a system were to me people who had never experienced what a cable would do in a system because in my then view, their system lacked "resolution". They were brushed of. Oh! I read about the Randi challenge and found that a little over the top so much back and forth there were ... So Cable made huge differences.

Then came an interesting in which a fellow WBF forum member participated. His system doesn't lack resolution by any stretch nor his understanding of great components even less his ears. He wasn't able to discern between his cables and some pretty basic cables.. I was a perplexed and conducted my own... Well I wasn't able either. I could not discern between 6 AWG copper cables and a very, very , very, expensive cable... Later the same month I conducted under similar conditions (nothing scientific, no DBT but knowledge of what was playing was removed) I tried the same thing with Digital front end with some modicum of rigo, RAT Shack SPL meter was used, to try the same experience with front ends .. I could really easily discern between a good CD player and Burmester DAC and Transport, almost consistently .. that wasn't anything that could be published even on a blog but it opened my eyes on the basics of sighted bias .. pun intended.
I began paying attention to how our mind cloud or evaluation. Not that I did not know it but I did believe that we, audiophiles, may have special abilities. I also quickly add that I continue to believe in what some call eduction and I do call "Training" . To me a listener can be trained to hear better or to see better. to discern differences that would leave the un-educated flat. I was a photographer back in the days .. I was interested int he Zone System and began to pay attention to lights variation and to translate it in shades .... So there I began to look at things differently, I began to open my mind to the humbling fact that our ears are not very reliable. We can be trained but removing most biases is difficult. It is almost humiliating but in the end liberating. Our senses are easily fooled.. That much I know and we actually all know it but there is a fear to admit it IMHO. It is as I said humbling ubt in some instances humiliating. It brings us to a "normal" level. The only thing we may have as an advantage is the Audiophile education, the training which allows us to pay attention so as to discern more of the differences else, physiologically we are even at a disadvantage as we age ... I remember that in my youth I could hear 20 Khz .. easy and piercingly so. Now despite my very healthy (or so says my audiologist) and above average hearing acuity, I can barely make it to 18 KHz, actually 17.8KHz.
That has made me be more realistic and open my whole mind to the Marketing and at the end profit aspect of High End Audio. The manufacturers are in it to make a buck or two or many. If they can play with our mind .. The more they will sell .. So the emphasis on an above science stance many of the companies take or of special research or of the inability of science to explain music or the Art of Music... While their stated goal goal is not to MAKE music but to REPRODUCE it as it is in the medium ... I began casting a suspicious eye and mind and attitude to the mega-priced components the 30K cables , the 100K amps and preamps and the half million dollars speakers. i also began to look at the price of upgrades .. sometimes a sizable fraction of the original price for few, subtle changes .. Of course Subjectivity weighs in and these changes to the fans are HUGE .. I remember being almost outraged by Wilson Audio charging $35K to upgrade the MAXX which when introduced was around $35K.
I also began quietly to see how the minds of audiophile was getting trained to accept the notion of "Price Class" .. You now the huge pile of Bovine Manure that a 10 K components cannot be better than a 100K one... (For Those in Tubes an honest and long audition of the ASL Hurricanes would dispell that notion in a hurry by experiencing how less than $5000 monoblocks can beat the pants of most tubes amps out there, but I digress..) ..

In the end I am most satisfied. I know now what NOT TO DO. I know now that I will focus on the best room I can build , drop in the best speakers my funds allow.The search is going to be extensive but I think I have my mind on two, very different speakers, both of distinction. Both not very well known... I will use at least 3 DIY subs, one of the area where DIY routinely outperforms commercial. The source shall be Digital PC-based with most likely a Professional-sourced DAC (Did someone say from Switzerland??? ). For fun I may get an analog front-end since I have been seeing R2R at more than decent price on e-bay and the likes . Electronics will likely be between Burmester and Spectral depending on funds availability .. likely none of the top components either produce, Cables shall be heavy gauge Copper (64 or 6 AWG). I will use a Double conversion UPS and this system may not change for a good while .... There is so much music to listen to an so little time

TO BE ON TOPICS ..

I am not entirely what now is termed an obectivist. I do not believe that measurements as they are taken right now tell the whole story. I believe that measurements may eventually tell most if not the whole story but we are far from that. I believe in long term audition and I believe in a mixture of following the measurements and long term audition if possible. I am by no means afraid of measurements.

Interesting post and thank you for that. It parallels somewhat what Tom Nousaine told me. He was a very big subjectivist when he became involved in the hobby and felt everything made a difference. What opened his eyes and made him start questioning himself was he was switching cables to tell the difference in sound back and forth. Everytime he was amazed at how much better the new more expensive cables sounded until he realized on one of the switches he had failed to actually switch them. It was then he started investigating expectations in audio.

 

[Ethan Winer]

consider I showed two such products with negligible measurements.
Distortion was lower than 0.001% ... this also ignores my point where I show two totally different products that measure negligible differences for FR and THD (which also reflects negligible IM)

Okay, so the next step is to do a DBT listening test and see if they really do sound different while having distortion that measures below what should be audible. Look, this is not complicated. If two devices really do sound different, proven with a DBT, then whatever difference there is can be measured and known easily with basic tests of the four parameters.

But it is YOU who is stating your 4 parameters as fact for what we hear in audio reproduction So the onus is also on you

That's a common logical fallacy because you can't prove a negative. You can't prove that Martians don't exist, but you can prove that flowers do exist. I avoid words like "what we hear" because what we hear changes from moment to moment. This is a big problem, and I wish more people understood that their hearing is not reliable.

If you believe there's more than just those four basic parameter categories, the burden is on you to say what else there is. Or at least come up with a plausible theory. As I said earlier, this has come up dozens of times over the years I've been talking about these four categories. You are not the first to say there's more to audio than that. But so far nobody has ever shown another parameter category. At least not one that makes sense logically.

I went as far as finding two products that subjectively are different and also had measurements showing negligible differences

Was the subjective listening done as a controlled blind test? If not, then I discount that as evidence of anything.

Since you brought up the burden of proof, I'll put it back at you: Please explain what accounts for two amplifiers that measure similarly but sound different. Please be very specific as you describe what accounts for the difference in sound quality, and why it doesn't show in measurements of the four standard parameters.

--Ethan

 

[Ethan Winer]

Then came an interesting in which a fellow WBF forum member participated. His system doesn't lack resolution by any stretch nor his understanding of great components even less his ears. He wasn't able to discern between his cables and some pretty basic cables.. I was a perplexed and conducted my own... Well I wasn't able either. I could not discern between 6 AWG copper cables and a very, very , very, expensive cable... Later the same month I conducted under similar conditions ...

No need to quote your entire long post, but that was a great read. I wish everyone who discounts "science" and measurements would take the time to read and understand what you wrote.

--Ethan

 

[Orb]

.....
Was the subjective listening done as a controlled blind test? If not, then I discount that as evidence of anything.

Since you brought up the burden of proof, I'll put it back at you: Please explain what accounts for two amplifiers that measure similarly but sound different. Please be very specific as you describe what accounts for the difference in sound quality, and why it doesn't show in measurements of the four standard parameters.

--Ethan

Mulling over whether to fully respond as I think we probably reached a logical conclusion (meaning probably as far possible to go without going full circle) but just wanted to quickly pick up on the last point.
There are potentially several reasons for two products that measure similarly but sound different, the most obvious is the various chemical and cognition type biases that can skew both perception and our throught processing and yes this can and does happen just like it affects everything we do in our lives day to day both at work and leisure time.
But focusing on the primary topic of this thread and that of measurements.
It is; what is the purpose-scope of the test initiated and what are its limitations, I am not saying the way we measure is the limitation as I feel we can measure everything we need to relating to audio but is the right test and relevant configuration-tools for what we want used.

Most existing tests used in audio must be very specific and restricted so it can be repeatable while potentially triggering a specific behaviour or pattern (in scientific studies could be perception tests as per Toole,Fletcher,etc or stability-performance-trait in an audio product).
That is saying it in a basic way so hopefully no-one is going to get to pernicky about that.

The implication is are the test procedures detailed enough beyond their given scope?
As a classic example was the IM distortion where most reviews and manufacturers may use 2 tones, however as per the link I provided Nelson shows how IM Distortion becomes much worse-complicated when additional tones are added.
So existing tests would suggest two products measure identically, but taking the test further it shows they may not, so two preamps could measure comparably close to each other with existing 2 tones and hence measure the same but when we have many tones (that would also vary due to notes played and instrument) we could have audible distortion.

Another example relating to FR, in the real world of power amps the FR can be flat from 20-20khz and shows two products measure the same, however another factor is output impedance of the power amps and the characteristics of the speaker.
So on a 8ohm to 6ohms load may look truly flat within 0.1db, but 4 and 2ohms could be flat but down by 0.5db, so if lucky choosing two power amps with different output impedance it is possible to see this pretty distinctly.
However, with two well designed power amps with good output impedence they will look very similar and so in theory the two measure very similarly.
However run a practical real load (see speakers impedance-phase) and you potentially see dips-bumps on one or both at different places along the frequency.
But without that simulated load we would had two power amp that sounded different but measure comparably close enough to each other to be audibly transparent.
The Stereophile link below touches on the real load and I feel if you read it (1st paragraph), ties in with what I said above: "Most existing tests used in audio must be very specific and restricted so it can be repeatable while potentially triggering a specific behaviour or pattern (in scientific studies could be perception tests as per Toole,Fletcher,etc or stability-performance-trait in an audio product)"
http://www.stereophile.com/reference/60/


So at what point does one say the test is complete or conclusive?
It depends why your doing the test in the 1st place.

I chose the distortion and FR as it fits well with what your saying on those two parameters but also showing how measurements may look close enough due to the scope-procedure and config-tools of the test done.

You know I do wonder if a simulation of certain notes-chords from an instrument would make sense to see the behaviour and characteristic of IM distortion on a preamp in the same way we have the speaker load simulation for power amp.
The problem is defining a simulation that makes sense from a repeatable and worthwhile correlation/presentation purpose.
Of course this would not cover all factors-parameters-possibly perception related descriptions, but just curious thought.
Its late so going to leave it at that, woot we all say

Cheers
Orb

 

[Phelonious Ponk]

That has made me be more realistic and open my whole mind to the Marketing and at the end profit aspect of High End Audio.

Great post, Frantz, and my path to semi-objectivism is similar. But the excerpt, above, from your excellent post is interesting. I spent my career in marketing and I can tell you without hesitation that most of the high end hardly markets at all, and when it does, it is not particularly good at it. Audiophiles, and their press, sell this stuff - good, bad and completely defying credibility - to themselves.

I would love to see a psychological study of the phenomenon.

p

 

[terryj]

hiya frantz, well thanks for the detailed response, much appreciated.

I'm extrapolating here, but this whole area of perception and expectation must be a weird one! I mean, there WAS something you were hearing when you were a 'cable guy', and I'd imagine consistently and 'repeatably'. So it is not strange that a person would be adamant that 'hay, I DO hear it', because..well.. they do!

I guess what can be hard to believe is how utterly our perceptions can be skewed. One argument thrown back is 'hey, you don't need dbt's to get thru everyday life do you'. Well, I spose the logical fallacy is that our normal perceptions in everyday life are always to be trusted (hence perfectly good for audio too). When you sit down and think about it, everything in everyday life IS completely coloured by everything that has gone on before in our life, our thoughts, previous decisions, previous experiences, conclusions made on a variety of topics.

Good luck teasing that ball of wool out, yet as it is ALL we have we assume it is all normal and logical and that any decision made is based on logic and rational thought, it ain't. Not by a long shot.

One thing I missed in your answer, when you were a 'cable guy', what did you think of those 'opposing' you? Were you as ready, for example, to dismiss them with stuff like 'ha, you just go and enjoy your test tones' yada yada?

Not that it matters, but you are in a unique camp, hence more able to see both sides of the argument a little more clearly. Perhaps.

Randybys, I have met quite a few objectivists who became that way from very similar events as you describe for Tom...the producer's slider if you will.

Hi orb. I don't think any of us have ever said the simplistic, limited measurements we usually see are sufficient for a full understanding of audio. I think what most are saying however, and you seem to agree with, is that we (theoretically at least) are able to measure anything we may be able to hear. Whether we currently do is very much debateable!

Ha, if we define distortion as 'any alteration to the signal' then we could say that all audio flaws come under the category of distortion! Ethan has narrowed down that general thing into four categories, some of which can be further subdivided. You seem to have been arguing of late between IMD and THD, or whatever, can't remember now as I type! But, still distortion no?

If those four are as simplistic as we feel the measurements can be, it does ONE thing at least, it narrows down WHERE to look for any 'new or improved' measurement in audio. I feel at least.

Audiophiles are often looking for that missing measurement somewhere, and will happily take it in 'quantum tunneling' or equally left field ideas. I personally don't think that a fruitful field to plow, but refinements within the four parameters very well could be. As you have been arguing.

One last thing, frantz' last para got me wondering..I may even start a thread on it.

 

[silviajulieta]

It was already explained that percentage importance is not related to percentage of budget.



It was already explained that the source music is outside of the reproduction path, and thus has nothing to do with "gear fidelity" which is what this thread is about.

Not to editorialize too much, but it's a waste of time for everyone when the same points have to be made repeatedly.

--Ethan

Dear Ethan: I'm refering as a source, in the audio system context and in my case through analog alternative, the phono cartridge.

I tryed to understand that the %% are not on budget because means almost nothing. Those %%% IMHO have to be in quality performance and overall contribution about. I don't necessary need like you db's here " o's and 1's " there to rank under quality performance importance the different audio links in the audio chain, I use measurements/specs where I need it but it is not my sole " weapon ".

IMHO the relative importance of each audio link or " group/set of links " reside in how/weight contribute in the overall audio system quality performance and from this point of view each one person audio link ranking is " totally open " .

90% for room/speaker is not in my mind, yet. The best/perfect that any audio system can do is not degrade the audio signal, even no audio system link can improve in anyway the original source ( phono cartridge ) audio signal . As good your source as better will be the overall quality performance if we take care on the audio signal in each link in the audio chain where room and speakers are links on that audio chain. No way for me that can exist an audio link with 90% of importance over the other audio links: 90% of something is only a dimish or don't understand the " weight "/role/importance of all and each audio link in that audio system.

A bad cartridge IMHO is worst that a bad room because ( between other things ) you can't improve the quality performance of that cartridge and you always can improve the room characteristics so that source/cartridge is way way important and weighty. My way of thinking is a little different from yours, thank's God because that fact makes exiting " the audio life " and less " boring ".

Ethan if we want to be a little in the " irrational level mind " we can think that all the audio links in the audio chain are important but the room just because with out any of those audio links we can't hear nothing but even with out " room " we can hear a music performance through the audio system!!!

Regards and enjoy the music,
raul.

 

[Ethan Winer]

There are potentially several reasons for two products that measure similarly but sound different, the most obvious is the various chemical and cognition type biases that can skew both perception and our throught processing

That's been my point all along! Two amps may test the same and seem to sound different, but they don't really sound different - people only think they do. So that doesn't count as sounding different.

So existing tests would suggest two products measure identically, but taking the test further it shows they may not, so two preamps could measure comparably close to each other with existing 2 tones and hence measure the same but when we have many tones (that would also vary due to notes played and instrument) we could have audible distortion.

But that's not measuring the same either. That's simply not having a complete set of measurements.

Another example relating to FR, in the real world of power amps the FR can be flat from 20-20khz and shows two products measure the same, however another factor is output impedance of the power amps and the characteristics of the speaker. So on a 8ohm to 6ohms load may look truly flat within 0.1db, but 4 and 2ohms could be flat but down by 0.5db

That's not measuring the same either. That's simply not measuring at the correct place in the path. If you want to know if the amp is truly flat including the amp's output impedance versus the speaker's input impedance, you solve that by measuring at the speaker terminals. Of course, with a competent amp having a suitably low output impedance, this interaction goes away.

So at what point does one say the test is complete or conclusive? It depends why your doing the test in the 1st place.

Yes, though I address theory mostly, more than practice. In this case the "theory" that two amps can measure the same yet sound different is easy to disprove.

I do wonder if a simulation of certain notes-chords from an instrument would make sense to see the behaviour and characteristic of IM distortion on a preamp in the same way we have the speaker load simulation for power amp.

I don't see why. Musical notes are simply a bunch of sine waves at various frequencies, levels, and time relationships. So anything that can be tested using real music can be tested just as well using appropriate test tones. If two tones aren't enough then use three. Or use 25. Or whatever is needed to totally reveal all of the circuit's flaws.

--Ethan

 

[Ethan Winer]

No way for me that can exist an audio link with 90% of importance over the other audio links

That's why in my percent allocation I showed frequency response deviation of electronics, versus speakers, versus a typical room. By that metric the room certainly does degrade the audio 90 percent more than electronics and wires.

Your point about photo cartridges is a good one - being mechanical transducers they have similar variability and resonance etc as loudspeakers. They also have resonances similar to rooms. Though rooms typically have many resonance, where a cartridge has a single main one.

A bad cartridge IMHO is worst that a bad room because ( between other things ) you can't improve the quality performance of that cartridge and you always can improve the room characteristics so that source/cartridge is way way important and weighty.

Sure you can improve the cartridge! You do this by replacing it with a better model. Just as you do with speakers or even a room. Again, I was being partly tongue-in-cheek with my 90/9/1 proportion, but it's not really that far fetched.

--Ethan

 

[silviajulieta]

That's why in my percent allocation I showed frequency response deviation of electronics, versus speakers, versus a typical room. By that metric the room certainly does degrade the audio 90 percent more than electronics and wires.

Your point about photo cartridges is a good one - being mechanical transducers they have similar variability and resonance etc as loudspeakers. They also have resonances similar to rooms. Though rooms typically have many resonance, where a cartridge has a single main one.



Sure you can improve the cartridge! You do this by replacing it with a better model. Just as you do with speakers or even a room. Again, I was being partly tongue-in-cheek with my 90/9/1 proportion, but it's not really that far fetched.

--Ethan

Dear Ethan: I don't know if you are abble to do it but I hope you could have a specific answer on what Orb ask you several " years " ago: validation on your four parameters hipothesis, I can add scientific/objective validation on that your statement and please don't answer with a question or questions.
IMHO I think that that subject is really important as to " leave " it in the " dark ".

Btw, I see that today your " tone/attitude " is a little different from in the past when you posted something like these: " hey do you have db's on hand? NO, then is useless " or " do you have a DB test? No then is futile to go on " and the like.
When one of the persons in a " debate " close the " door " then debate is ended. The other important thing IMHO in a debate is try to understand the other " side " between other things because normally in a debate both sides have different knowledge level.

Thank you in advance .

Regards and enjoy the music,
Raul.