| Prune |
When I read D Self's writings, such as this one:
http://www.dself.dsl.pipex.com/ampi...do/subjectv.htm
I feel very confused. As someone who has the pretense of being a rational scientist, swearing by my copy of the Skeptic's Dictionary, I feel I should agree with that article in whole, yet here I am reading this forum (and worse, Audioasylum), using silver/teflon wiring, Auricaps, and seven dollar resistors -- all the while knowing that a blind or null test will show me my folly, and thus avoiding it...
Sorry, destroyer X, for this threadjacking. |
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| traderbam |
| quote: | | I feel very confused. |
I'm not surprised if you have just read Self's diatribe. Unfortunately, it appears to me that he cannot really explain why people can hear certain differences and therefore attempts to both deny those differences by suggesting analogs with several other areas of science and then heads down the route of greater and greater refinement of a set of measurements which only lead him to be more skeptical about whether people can really hear what they claim to. Then this always leads to the implication that humans are basically nuts and terribly unreliable. He uses the term "subjectivist" in a derrogatory way.
| quote: | | D.Self writes: I believe this to be a representative sample, and we appear to be in the paradoxical situation that the most expensive equipment provides the worst objective performance. Whatever the rights and wrongs of subjective assessment, I think that most people would agree that this is a strange state of affairs. |
I find this interesting. Self acknowledges here that objective listening (let's not unfairly discredit the witness by using the word "subjective") has an poor or even negative correlation with objective performance measurement that Self uses. But rather than drawing the conclusion that his measures are inadequate, he prefers to question the witness.
Of course, if you want to make a living out of being an audio guru you cannot go around saying "I don't know, I just haven't figured it out yet". Or "I have all these theories but my amps still don't sound that good yet". No, you have to go around saying "Very few people have my insights or rigorous approach, why not buy my book and learn from my research or sign up for one of my courses?"
IMO people, using their ears, are a much more reliable and objective source of audio performance assessment than ANY scientist or other using measurement equipment or simulators. We can all tell a live saxophone or voice from a recording - easily. Hifi simply isn't very realistic yet and the defects are quite audible.
The greatest folly of scientists and engineers is to IGNORE THE EVIDENCE and create a comfort zone within a re-assuring process or theory. Unfortunately, I see no evidence whatsoever on Self's site of objective performance measurement or comparison using PEOPLE. So, although I have never heard the Self amp myself, it wouldn't surpise me at all if its greatest followers are famillies of oscilloscopes sitting in their lounge of an evening listening to their favourite sinewaves. |
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| AKSA |
Traderbam,
I find your notion of families of oscilloscopes sitting happily in their lounge rooms listening attentively to their favourite sine waves absolutely comical, and entirely apt.
Ne'er was there a better description of D. Self's often dissonant view of the world...... Absolutely my feeling, too.
Rarely do I find humour amongst the prostatic gumshots of this forum, but this one was genuinely funny, and I loved it.....
Thank you!
Cheers,
Hugh |
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| traderbam |
My pleasure, Hugh. Glad to be of service.
Brian :cheeky: |
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| destroyer X |
Congratulations!
Very good analogies and psicoacoustical behaviour, hehe, unfortunattelly i could not understand some words...not problem
Me good
You great
Carlos |
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| destroyer X |
Walking together the street, and entering a shop to buy audio amplifiers!
This way, let me made the obvious conclusion, my pleasure, equipments must be made for ears, for human ears, and adapted to some small cultural differences too.
I am shocked till today.... looking myself into a mirror and asking myself....am i bassy guy.... the Englishman, once, told me boomy....i am walking the street with a persecution delirium.... when someone looks at me.... i always thinking :
- "he nows!, i am a bassy, boomy guy"
What a shame to me..but now serious, if the man was rigth, and the one i trust, my country needs 6 db plus low end.
Carlos |
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| janneman |
| quote: | Originally posted by traderbam
[snip]IMO people, using their ears, are a much more reliable and objective source of audio performance assessment than ANY scientist or other using measurement equipment or simulators. We can all tell a live saxophone or voice from a recording - easily. Hifi simply isn't very realistic yet and the defects are quite audible.
[snip] |
Traderbam,
This may be your opinion, but that's all what it is. It flies in the face of a long history of human unreliability when it comes to perception, be it sound, vision, or just repeating a story.
You don't hear with your ears, you hear with your mind. A person can listen to the same music, on the same system, same time of day, on two days and report different perceptions. Witnesses present at an accident often report different course of events. After reading a newspaper report of the event they were present at, they report a different course of events, because they can't keep their own experiences and the newspaper report apart.
An example: People witnessing an accident are asked about how much time there was between the accident and the arrival of the ambulance. They give wildly differring times. Sure, because their WAS NO AMBULANCE. When confronted with that, they get angly and aggressive. This was an accident, for Pete's sake. OF COURSE there was an ambulance! See what I mean?
Let me give you another example of people rationalising their perceptions with their believes. This involves a famous neuroscience case, where a patient has a rare defect in his brain that prevents him to be aware of his right body side. He cannot feel, hear, see anything at the right side, he is also not aware of his right arm and leg.
The doctors are fascinated and try to force him to acknowledge he has a right side. One doctor sits in front of him and takes the patients right hand in his hands so the patient clearly sees it. He then asks him: how many hands do you see? Answer: three. Question: don't you think that is strange? Answer: No, why? You have three arms, so naturally there are three hands.
Now this is no joke, it is a classic case that has been studied over and over again. This patient was an intelligent, fully functioning (except for this defect) human being. Neurophsychology is replete with less extreme examples of cases documenting the extremely cheating nature of human perception. I admit this one is a bit extreme, but it also clearly indicates that people will do WHATEVER is necessary to hang on to their believes. And you call them reliable, objective? You've got a lot of humour, my friend!
Jan Didden |
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| PMA |
Jan,
Why are some people able to describe sonic difference of the two amps (black boxes), not being informed about their technical differences, both amps should be "same sounding" according to traditional a la Self explanation? Why do the different people come with similar sound descriptions independently, not knowing assessment of the others?
Some time ago I also had agreed with D. Self's scepticism, especially when I had not performed my own listenning tests. |
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| janneman |
I am not rooting for Self here. I have other gripes with him, and I think his pathetic hanging on to classical topologies stifles innovation big time. He is a smart and intelligent man, if he only had a more open mind he could do great things.
I also accept that people can hear differences between amps, although I could (if I took the time, which I am not prepared to do) come up with a long list of cases where people couldn't here a difference between different amp (that measure differently) under blind conditions.
What I strongly protest is the idea that somehow people, with their track record of unreliability, bending facts to fit their beliefs and full of prejudice, are seen as objective and reliable. Evidence to the contrary abounds on this forum.
Traderbam himself is a prime example. To support his case, he states flatly "Everybody can hear the difference between a life voice and recording" or something to that effect. Really? Has he or "everybody" tried it in a controlled and blind environment? Well, I have. I have been present at an event where recordings of a chamber quartet were compared with the quartet life. I tell you, it was damn difficult, and I (and others present) frequently got it wrong. And we cheated a few times, because we saw that on some takes the quartet was just going through the motions and not really playing. That saved some reputations, but it was nothing to be proud of. Shocking, to say the least.
Jan Didden |
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| traderbam |
| You bought his book, didn't you Jan? :clown: |
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| janneman |
| quote: | Originally posted by traderbam
You bought his book, didn't you Jan? :clown: |
Yes of course, both. Plus a couple on perception, human behaviour, the relation between mind and matter, critical listening etc. No use discussing things you have no clue about.
I would also buy your book, if you would only write one.:D
I could recommend Edelman's "Bright Air, Brilliant Fire".
Jan Didden |
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| traderbam |
Ok Jan,
I'll let you know when my book is published!
Responding to your earlier points, I simply don't see the relevance of them.
Audio is intended for human consumption. So to deny or avoid judging audio on human response seems downright unscientific and "on another planet" to me.
It is just a non-starter to discredit the intended consumer. Where's that going to get you?
It would be like Ford Motor Co being told by Jan that one in a million humans think they have 3 arms so you must not test your new designs for customer acceptance by using customers. No, you'd better sit a PC in the driver's seat and ask it how much it liked the handling at the end of the test.
Keep it real, folks. |
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| sam9 |
This is degenerating un to the old rationalist / subjectivist (measurment vs listening) argument. Yawn.
No doubt there are amps with ultra low noise and distortion that sound bad for one reason or another. But here is the problem with evaluation by listening: http://www.pcavtech.com/soundcards/...sound/index.htm
Play the first two examples. Some of you will say example one sounds better, some example two . (any one who likes thre or four -- well I just don't know what to say about that!). Me I like example one better until after dinner, then as the sun sets and I relax with a little single-malt Scoth two sounds better. Worse still if I walked in to a room listened blindly to just one or two and was asked to identify it, my sucess rate would be better than random but not a lot unless I really focused.
Measurements have the potebtial of being reproducable and communicatable over space and time. But if ten people try to me(independently) to describe the difference between example one or two (expecially without knowing the physical difference) the cances of consistancy are small, there would be little chance I could reproduce the differences and I doubt I could make much sense out of the various adjectives used or relate them to my experiences. |
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| JensRasmussen |
About the different books available, I enjoyed both D. Self’s and Sloane’s but would like to get my hands on other books that cover the same range/type of amps that these books do.
If anybody could point me to any titles it would be greatly appreciated.
\Jens |
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| janneman |
I'm sorry, I can't follow you.
Yes, audio is for human consumption, what are you driving at? My point was that it is a long standing, proven fact that humans are notoriously unreliable as far as their opinions and perceptions go. Therefore, I strongly protest your view that humans are the most reliable and objective "entities" to judge the relative merits of amplifiers (and maybe other audio equipment).
Now, I fully accept that, as with cars, there's something for everyone on audio. Some like tubes, some like ss, some like pwm. For whatever reasons. But your term "objective" is at odds with the terms "like" or "opinion". I don't see how one can develop amplifiers and make progress towards "hi-fi" without measurements. At the end, you may want to listen to them to convince yourself they sound good, or to try to find a correlation between measurement differences and possible audible differences, but then you must also accept that your listening can throw you completely off course as to the general acceptance of your amp by the public at large.
Why is it that for the last 20 years or so there was (in my opinion) no real progress in amp development? We gyrated from low THD, to low feedback, to nested feedback, to tubes to hybrids, and around again. And they all had something going for them, and they all had their enemies. I think this is precisely because humans are decidedly un-objective. Something that is new, elitist or whatever is perceived as better. Why do car models change every year or so, without the actual roadhandling or performance changing? Isn't that a similar reason? Why would people pay a hefty premium to get an Audi, while being aware (or maybe not) that it is just a Volkswagen in a more expensive suit? Because the more expensive suite is perceived as covering a "better" contents.
Why do some manufacturers of hybrid amps put tubes behind a transparent window so you can see that glow? Because it does influence the perception and buying decision, NOT because it influences the sound. Man, we are sooo gullible!
Because humans have feelings, pet peeves, emotions, prejudice etc, and, again, are decidedly un-objective. In other words, the most unsuitable "tools" to base any engineering decision making on, except maybe marketing engineering.
Jan Didden |
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| traderbam |
| quote: | | Measurements have the potential of being reproducable and communicatable over space and time. |
Of course they do. But so what? Herein lies the crux:
Unless you measure with a human your measurement is INDIRECT and unreliable by definition. It is only relevant if you can evaluate the correlation between the measure and human judgement of the sound. And you cannot do that without humans! It's as simple and as thorny as that.
Self does not appear to do this.
You can have the most detailed and creative bunch of measurements in the world but if they don't correlate with performance they are of only intellectual value at best.
Once you start saying you don't want humans in the design process because they aren't as consistent as your oscilloscope then you have lost the plot. Many have lost the plot. |
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| traderbam |
| quote: | | I don't see how one can develop amplifiers and make progress towards "hi-fi" without measurements. |
I certainly never said that.
| quote: | | At the end, you may want to listen to them to convince yourself they sound good, or to try to find a correlation between measurement differences and possible audible differences, but then you must also accept that your listening can throw you completely off course as to the general acceptance of your amp by the public at large. |
Designing a product for a particular target market is an entirely different subject. I am happy to discuss this later. It's off the discussion about Self's methodology and the design process for achieving better reproduction. |
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| Graham Maynard |
Hi Jan,
Is that the 'Real-life' V 'Recorded' session that was recently reported in the Hi-Fi press, possibly Hi-Fi News.
I can't find the magazine at the moment, but it was very interesting.
____________________________________________________
Hi Mikeks,
I am NOT writing about phase distortion.
What Destroyer is hearing arises when you loudspeaker load a Miller VAS C.dom stabilised bipolar class-B amplifier circuit, like the D Self Blameless. The change in reproduction is caused by load angle PLUS C.dom shift.
The output stage reverse commutates through a fraction of its crossover bias potential in order to create the differential stage error necessary for the input stage to lead-charge the C.dom.
It does not matter what you write in reply to me, I have heard the distortions, then I ran the Sims to investigate.
I have here been trying to pass on a method for circuit observation that matches what we hear, but this seems inordinately difficult !!!!!
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Hi Destroyer.
Your thread has aired ideas and opinions which are as different as the sounds amplifiers make.
At least Traderbam gave us a laugh.
Have you tried the 'Blameless' with different loudspeakers ?
It can sound so much better with simple loudspeaker systems and old fashioned full range drivers which do not use crossover networks. Simple loudspeakers generate much less back EMF and thus the choke and C.dom induced amplifier distortion effects are much less likely to be triggered at normal listening levels.
Cheers .............. Graham. |
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| mikeks |
| quote: | Originally posted by traderbam
Unless you measure with a human your measurement is INDIRECT and unreliable by definition.
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This is incorrect.....this was shown to be false years ago.....In fact the converse is true... |
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| mikeks |
| quote: | Originally posted by traderbam
The greatest folly of scientists and engineers is to IGNORE THE EVIDENCE and create a comfort zone within a re-assuring process or theory. Unfortunately, I see no evidence whatsoever on Self's site of objective performance measurement or comparison using PEOPLE. So, although I have never heard the Self amp myself, it wouldn't surpise me at all if its greatest followers are famillies of oscilloscopes sitting in their lounge of an evening listening to their favourite sinewaves. |
On the contrary....subjectivists have consistently ignored scientific evidence that their most sacred beliefs are in fact complete rubbish... |
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| traderbam |
| quote: | | This is incorrect.....this was shown to be false years ago.....In fact the converse is true... |
Good grief. :rolleyes: |
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| mikeks |
| quote: | Originally posted by traderbam
Good grief. :rolleyes: |
Indeed?!!
:rolleyes: |
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| janneman |
To Traderbam:
This statement was posted by sam9, you reacted somewhat vaguely (my pereption, pun intended) to it:
/Quote/
Measurements have the potebtial of being reproducable and communicatable over space and time. But if ten people try to me(independently) to describe the difference between example one or two (expecially without knowing the physical difference) the cances of consistancy are small, there would be little chance I could reproduce the differences and I doubt I could make much sense out of the various adjectives used or relate them to my experiences.
/Quote end/
This is exactly why you cannot just use human perceptions and opinions to communicate or discern qualitatively reliable about equipment. And, if we are taking ourselfs serious in our endeavour to make progress, it is required. Because we stubbornly refuse to acknowledge it, and stubbornly continue to try to communicate in this totally insufficient way, that audio is going around in circles for the last 20 years without going anywhere. Unless you call the rise of snake oil, magic cables and/or colored CD pens "going anywhere".
Jan Didden |
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| janneman |
[QUOTE]Originally posted by traderbam
quote:
I don't see how one can develop amplifiers and make progress towards "hi-fi" without measurements.
I certainly never said that.
quote:
At the end, you may want to listen to them to convince yourself they sound good, or to try to find a correlation between measurement differences and possible audible differences, but then you must also accept that your listening can throw you completely off course as to the general acceptance of your amp by the public at large.
Designing a product for a particular target market is an entirely different subject. I am happy to discuss this later. It's off the discussion about Self's methodology and the design process for achieving better reproduction.
Traderbam,
On #1: Agreed. You never did, and I was not implying it.
On #2: It's off the discussion on Self's methodolgy, but so was my reaction to your earlier post. We are not discussing Self's methodology here, we are discussion the difference in views between Traderbam & Janneman.
Jan Didden |
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| SY |
| quote: | | We are not discussing Self's methodology here, we are discussion the difference in views between Traderbam & Janneman. |
And to that extent, please open a new thread if you want to hash it out. I have a couple things to say myself, but this isn't the thread to go in that direction, OK? |
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| janneman |
Ok Stuart,
Got your point, it's no longer on Blameless (I think), but on the "useability" of human perception and reporting. You could split this thread off with your Mod hat on, but I don't intend to continue this for days on end. I think I explained my views, and tried to argue why I think the way I think. Anyone can agree or disagree.
Jan Didden |
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| ALW |
I'm with Traderbam here, whilst he's not saying measurements do not have value, they are as he states, by definition indirect.
Anyone who designs audio gear without recourse to listening is totally missing the point, completely.
It's whole raison d'etre is to be listened to. It's purpose in life is to create emotional responses in human beings. It's about dancing, laughing, crying and all the gamut of human emotional response. Music has this effect on us, it's what makes us listen and what keeps my overweight **** glued to a listening chair for more hours than is healthy ;)
We don't go to live gigs and rate the performance on the distortion levels of the PA, we talk about the MUSIC, we dance, sing and feel an insatiable urge to join in (assuming the band are any good!). By most normal measures live amplified gigs are awful, yet those of us who go to them get something that most HiFi in my experience misses, that important 'X' factor. It's all about content over presentation.
Not one single piece of my test gear has a measurement button for the above categories, so we're stuck with the effect that it has on me when listening and trying to correlate that with any measurements I can find that seem to correspond with what I hear.
Sometimes one finds them in the most unusual places, but often 'internally' rather than the usual simplisitc 'external' measurements one sees performed.
One fact remains though, you cannot predict with any accuracy the emotional effect a piece of HiFi will have on a human from any of the measurements you can do. You can make some judgements about it's 'sound' but none about the *music*.
And yes these response vary, as the human brain and psyche is affected by the day to day changes around it, but over time, it all averages out, in my experience.
The ONLY measure that is ultimately of any significance to me is whether I get that 'one more CD' feeling, or whether I'd rather watch telly. Nothing else matters.
This is where Self et al get it totally wrong, he just misses the whole point of music reproduction.
...and look what happened to TAG Mclaren whilst he's been head designer there :)
Andy. |
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| moamps |
| quote: | Originally posted by JensRasmussen
[B]About the different books available, I enjoyed both D. Self’s and Sloane’s but would like to get my hands on other books that cover the same range/type of amps that these books do.
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Hi,
Good book about speakers and amps is
W. Marshall Leach
"Introduction to electroacoustics and audio amplifier design" ISBN 0-7872 7861-0.
Regards
Milan |
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| carlosfm |
| quote: | Originally posted by janneman
I also accept that people can hear differences between amps, although I could (if I took the time, which I am not prepared to do) come up with a long list of cases where people couldn't here a difference between different amp (that measure differently) under blind conditions.
Jan Didden |
I don't trust every people to give a reliable oppinion about the sound of an amp.
You learn how to listen, it takes time, it takes plenty of experience, it takes listening to many things, comparing, testing.
Suppose you're not experienced in listening (I'm talking hi-fi, music, don't take me wrong) and you have an experienced guy with you.
You are testing two amps.
You listen, and then you change the amp.
At first it's ok for you, you can't notice any change.
Then the guy says something like this: "look, I hear a sound that was maskerated with the other amp, it was unrecognizable. just listen, there's a piano on the background. Always. During all the music".
The guy continues: "follow the tune, listen to the music, follow it, you must understand it without any stress, or the system is not good".
You change the amp again and you can't listen to that piano.
Suddenly the difference becomes so obvious to you that you can't realize how you missed it.
And you'll miss things like this plenty of times until you're good at listening and detect subtle changes in the musical content.
After all you're listening to an amp (a system, in fact) but you don't concentrate on it, you just listen to the music.
It's the music that matters.
Enjoy the music!:cool:
:angel: |
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| rfbrw |
| quote: | Originally posted by janneman
<snip>
This is exactly why you cannot just use human perceptions and opinions to communicate or discern qualitatively reliable about equipment. And, if we are taking ourselfs serious in our endeavour to make progress, it is required. Because we stubbornly refuse to acknowledge it, and stubbornly continue to try to communicate in this totally insufficient way, that audio is going around in circles for the last 20 years without going anywhere. Unless you call the rise of snake oil, magic cables and/or colored CD pens "going anywhere".
Jan Didden |
If I may be so bold, can I ask what you consider to be progress in the context of audio? |
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| JensRasmussen |
Thanks Milan,
I read that too some years ago, but mostly the speaker modelling section.
\Jens |
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| janneman |
| quote: | Originally posted by rfbrw
If I may be so bold, can I ask what you consider to be progress in the context of audio? |
Not an easy one, true. But I would look for things like a clear direction that the majority of listeners/users would consider "better" than the previous one. Some kind of general consensus that says, yes, using this type of topology or component types gives us a generally recognised step by step better audio performance, meaning that users/listeners clearly tend to prefer certain types of equipment over others. I know I am vague, I sorry, maybe I can better say what is NOT progress: Every year new "concepts", technoglogies, "breakthroughs" but in fact turning around in circles as I said before. Today it is low feedback, yesterday is was low THD, tomorrow it is hybrids, but without going anywhere.
Look at the hype on types of capacitors, with or without plastic jackets, and then with a jacket with a specific chemical composition, that divided again in different COLORS of jackets of specific chemical composition. That is what I call going around in circles, having a good time, but NOT about progress in audio.
Jan Didden |
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| janneman |
| quote: | Originally posted by ALW
[snip]It's whole raison d'etre is to be listened to. It's purpose in life is to create emotional responses in human beings. It's about dancing, laughing, crying and all the gamut of human emotional response. Music has this effect on us, it's what makes us listen and what keeps my overweight **** glued to a listening chair for more hours than is healthy ;)
We don't go to live gigs and rate the performance on the distortion levels of the PA, we talk about the MUSIC, we dance, sing and feel an insatiable urge to join in (assuming the band are any good!). By most normal measures live amplified gigs are awful, yet those of us who go to them get something that most HiFi in my experience misses, that important 'X' factor. It's all about content over presentation.
[snip]One fact remains though, you cannot predict with any accuracy the emotional effect a piece of HiFi will have on a human from any of the measurements you can do. You can make some judgements about it's 'sound' but none about the *music*.
And yes these response vary, as the human brain and psyche is affected by the day to day changes around it, but over time, it all averages out, in my experience.
The ONLY measure that is ultimately of any significance to me is whether I get that 'one more CD' feeling, or whether I'd rather watch telly. Nothing else matters.
[snip]Andy. |
Andy,
What have you been smoking? Amp design has nothing to do with "to create emotional responses in human beings. It's about dancing, laughing, crying and all the gamut of human emotional response"
What you describe is MUSIC. The amp has to faithfully reproduce the music, that's all. If you want an amp that messes up the music and creates an emotion of itself, sorry, that's not my idea of hi-fi. that electronic entertainment.
Those emotional responses that force you to put up yet another CD, and keep your **** glued to your listening seat is the MUSIC. ANY amp, even the lowly kitchen transistor radio, can rouse that in you, if you are in the right mood and if the music touches you.
Do you think that people in the 40-ies or 50-ies, when audio reproduction was mediocre at best to today's standards, people enjoyed MUSIC from their shellacs less because of a restricted freq response? Of course not, they had emotional responses and were moved to tears as well as any one of us.
You make a classical error by confusing music and it's effects with straight-forward audio engineering to provide the means to reproduce that music.
You said: "The ONLY measure that is ultimately of any significance to me is whether I get that 'one more CD' feeling, or whether I'd rather watch telly. Nothing else matters."
I 100% agree with that. What I don't agree with, is that that is depending on the value of the C.dom, or the color of the jacket of a certain plastic with a specific chemical composition that covers your supply capacitor.
Jan Didden |
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| ALW |
| quote: | | What you describe is MUSIC. The amp has to faithfully reproduce the music, that's all. If you want an amp that messes up the music and creates an emotion of itself, sorry, that's not my idea of hi-fi. that electronic entertainment. |
Yes Jan, that's entirely my point. How do you 'faithfully reproduce music'?
Music is not there to be measured, it's there to be heard.
An amp without music is a potentially expensive and useless piece of junk.
There are some amps out there though that totally fail to create those emotional responses in me. You feed good music in and you get soporiphic noises out. These amps, by all the normal measures, work fine.
My fundamental point is you, or anyone else, cannot measure the amp and predict the effect on the listener. The listener is the whole reason for the amps existence in the first place. There's little, if any, correlation between distortion and other 'standard' technical measures and the effect it has on the listener. To eliminate the listener makes the whole purpose of HiFi redundant.
If you cannot hear the difference and you are happy with the music you get, then stop and be happy!
| quote: | | Do you think that people in the 40-ies or 50-ies, when audio reproduction was mediocre at best to today's standards, people enjoyed MUSIC from their shellacs less because of a restricted freq response? Of course not, they had emotional responses and were moved to tears as well as any one of us. |
Exactly, demonstrating clearly that the 'mediocre' perfomance as you put it was clearly capable of doing the intended job. Some supposedly superior equipment is incapable of doing this, in my view.
To paraphrase an old quote, would you rather talk to Einstein on the telephone, or the doorman of the Ritz face to face? One is real and live and accurate, but I suspect the content of the telephone conversation will be far more engaging, despite it's bandwidth and dynamic limitations.
Andy. |
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| SY |
| quote: | | My fundamental point is you, or anyone else, cannot measure the amp and predict the effect on the listener. |
There's some interesting semantics wrapped up in this- if you are "listening" to an amplifier, your brain is going through a very different dance than if you're "listening" to music. In the former case, you're trying to find patterns whether they're there or not. And, whether they're there or not, you're likely to find them. |
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| ALW |
| quote: | | There's some interesting semantics wrapped up in this- if you are "listening" to an amplifier, your brain is going through a very different dance than if you're "listening" to music. |
In my case this is not true.
All listening tests are conducted over long timescales, days to weeks.
Over this timespan one can assess the change by examining my own behaviour - the music vs. tv test if you want.
I agree, short term listening doesn't work and is very easily confused. I would not be able to give a reliable, repeatable result on a quick A-B test, even over several hours. When I've tried to do this I have got it wrong in the past, what one thought was an improvement wasn't.
It's this fundamental issue that's being missed, in my view, it's all about music; all one picks up in a-b dems in my experience is tonal and amplitude differences, none of which have anything at all to do with the underlying musical messages.
There, that's enough of my feminine side displayed for one day :)
Andy. |
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| AKSA |
Would not the simple answer be to measure the amp during the prototyping phase for FR, Zout, stability, and distortion, then begin the listening tests?
Further, that these listening tests be performed in random over largish samples so that trends can emerge, be analysed and passed to the designer, with a view to tweaking?
No one doubts there is both a subjective and an objective aspect to amp/preamp/speaker design and appraisal. The first is consumer driven; the second technology driven. The product can only achieve commercial success by being sold, and people won't buy it unless the subjectives are right. There is no reason the two methodologies cannot exist side by side; it's been this way in the automotive world for a hundred years! Are we audiophiles that special?
In closing, I once designed an amplifier whoa to go without measuring its distortion, though I did measure FR, impedances, and operating points carefully. All componentry was chosen by ear, though I used a few sets of ears to assist. When finally a friend put the amp on an analyser (HP 339) I was quite surprised. It was very good, less than 0.045% THD at 20KHz at full load. This showed me (at least!) that subjective and objective measurement need not be constantly at war.......
Cheers,
Hugh |
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| SY |
| quote: | | Would not the simple answer be to measure the amp during the prototyping phase for FR, Zout, stability, and distortion, then begin the listening tests? |
Don't forget my particular idee fixee, overload performance. At least over in the tube world where I live, that accounts for the vast majority of perceived differences once the basics (level, freq response, distortion) are taken care of. No amplifier measurement suite is complete without understanding overload recovery into the range of loads and signals that the amp is expected to encounter. |
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| sek |
Hugh has an interesting point here, one that might lead us back to Self (pun not intended ;)).
I understand Self in that he always wants to keep subjectivist and objectivist views clearly distinct. But not in terms of the two fighting against each other. Rather he always wants to be shure what part of the discussion is objective and what part is subjective. Please note that Self did only state the opinion that an amplifier has to be good from an objectivist perspective in order to be good from a subjectivist perspective. He didn't claim it the other way round.
In his writings, I've never read (or can't remeber) that an amplifier that is good in a subjectivist way can't be good in an objective way, too.
BTW, I don't fully agree with Self on that the measurements he usually makes (and bases his opinion on) cover the full potential of influences that can determine the sound of an amplifier. I strongly don't believe in the existence of "unmeasurable" properties of amplifier sound (that is: I believe every difference in perceived sound that causally relates to the amplifier could be measured!). But I can imagine that Self is stuck too much on his particular measurement experience, equipment and point of view.
As for myself, I can clearly hear differences between differently sounding amplifiers. :D
But so far I could always relate them to objectivist properties of the amplifier in question (e.g. THD+N, FR), whilst finding this relation again is a subjectivist process!
I can imagine that the difference between what's explained by measurement theory and what's perceived by (subjective) listening can be approached by thinking about the way the measurements are taken.
There's a clear objective difference between an amp's measured frequency response with fully charged reservoir caps in response to a sweep and the slight dynamic changes of frequency response depending on multidimensional (non-orthogonal) properties like signal (change), load (change), supply (change), etc. :confused:
Sebastian.
edit: Yes, and SY's post fits in there too. Overload recovery doesn't seem to be part of most people's (and particularly Self's) measurement or listening practice... :D |
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| diy_audio_fo |
| quote: | Originally posted by SY
Don't forget my particular idee fixee, overload performance. . |
I want to state the obvious: if you want to lift 1 ton you need something rated for 1 ton or more.
If you want X watt on Y load you need an amplifier rated accordingly so you never overload it.
But SY, you are right, there will be somebody who turns the knob up until you get overload.
IMHO measuring many amplifier parameters in real time and on the field is impractical while amplifier overload can be easily monitored with cheap built-in circuit.
In a high feedback amplifier you can feed input-output signals to a difference amplifier with the output tied to a comparator that lights a led on the front panel whenever you have overload regardless voltage, current or load impedance
I have no experience with tube or low feedback amps but I suspect that can be used something like that too
When you see the led on you have the chance to turn the knob a little bit down ;-) |
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| janneman |
| quote: | Originally posted by SY
There's some interesting semantics wrapped up in this- if you are "listening" to an amplifier, your brain is going through a very different dance than if you're "listening" to music. In the former case, you're trying to find patterns whether they're there or not. And, whether they're there or not, you're likely to find them. |
This is very perceptive, and a view I haven't seen before. It also helps me better to understand some of the things going on in your mind when you are trying to compare something in the past (an experience) with something in the present (the current perception).
The way you "remember" the past experience is very much influenced by what you are currently experiencing or what you are searching for. Memory isn't absolute; it brings up whatever is important in the current context.
So, if you have say a memory of a birthday party, and someone asks you if Mr X was present, your memory brings up the parts that will allow you to answer the question, like faces you remember or a seating arrangement. It will not bring up the music played at the party, although it may hover at the edges depending how strong the memory and how complete you try to remember the scene. If you have a hard time to remember Mr X's presence or not, you are likely to bring up more and more details looking for clues. This will also take more time, as the brain tries to reconstitute internal sensory mappings and connections corresponding to the remembered scene (because that's basically how memory recall works, you try to reconstitute the brain's state at that time so you can 're-live' the situation).
What all this means is that what you remember is not an absolute truth but biased by what you are looking for and your own current values. If you stated beforerhand that Mr X was present, and someone disagrees with you, you have a big chance that you actually "remember" seeing him, even if he wasn't there. (Like in the ambulance story I told before). I think the implications for subjective audio testing are clear to see.
This is all fairly well established if you study the field, and generally it is assumed that it is evolution's answer on dealing effectively and efficiently with the immense amount of info we are constantly bombarded with.
So, SY, yes, I 100% agree with your observation.
Jan Didden |
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| janneman |
| quote: | Originally posted by ALW
Yes Jan, that's entirely my point. How do you 'faithfully reproduce music'?
janneman: In my book, you do that by trying to neither add nor subtract from the musical signal while it travels trough the sytem. I guess we agree on that, the controversy is about how we check that we accomplish this.
My point is that, as originally stated by Traderbam, if you use listeners to check it, you get nowhere, because each listener has his biases and preferences. And generally blind tests are rejected because they show no differences between amps, althoug WE the listener can clearly hear them in sighted tests. Can you deluge yourself any further??
In fact, these blind test show that we are there already, for practical purposes we have transparent systems. That's also why as I said before, we turn around in circles. We go from low feedback to tubes to class A to hybrids and back, but we are not going anywhere. Because we're there already, except for some obviously grossly inadequate designs. There are no bad amps. Look at the hype on gainclones. When you would have proposed that a few years ago, an IC, for Pete's sake, with not even a complementary output stage, and an open loop bandwith that's to tiny to see, you would be shot. BUT, it's simple, anyone can built them, they are a novelty, and see what happens, people report the most wonderfull and emotionally rewarding events just listening to a gain clone. Aren't people wonderfull?? We MUST (as an industry) come up with 'breakthroughs' or the buyer will strike.
[snip]
There are some amps out there though that totally fail to create those emotional responses in me. You feed good music in and you get soporiphic noises out. These amps, by all the normal measures, work fine.
janneman: Sorry, I have a hard time to relate to that. You listen to music you like, you're in the listening mood, and you don't enjoy it because of some infinitesimal THD factor that ruins your pleasure? Call me a sceptic.
My fundamental point is you, or anyone else, cannot measure the amp and predict the effect on the listener.
janneman: Indeed. NOBODY can predict the effect of whatever on the listener, although the marketing people go a long way. The effect on the listener is determined by a myriad issues in addition to the technical amp quality. Which strongly supports my view that using the listener as a "measuring tool" is utter foolishness.
[snip]
If you cannot hear the difference and you are happy with the music you get, then stop and be happy!
janneman: Hey, wait a minute! I am enjoying building and designing amps for their own sake. I also enjoy listening to music, and I very much enjoyed my iPOD while on vacation, emotions and all. I can, can't I?
Exactly, demonstrating clearly that the 'mediocre' perfomance as you put it was clearly capable of doing the intended job. Some supposedly superior equipment is incapable of doing this, in my view.
janneman: Same scepticism as above.
[snip]Andy. |
Jan Didden |
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| jh6you |
:scratch:
I have two audio systems having technical values, 20 and 50. At the same time, I also have my mood indication factors: 0.1, 0.2, ..., 1.0. My mood however actually works in this way: (0.1)^2, (0.2)^2, ..., (1.0)^2.
One evening, I was driving my car having car audio of value, 20, and was listening to CD music. That time my mood indication was 0.9. So, total effect of the music was 20 x (0.9)^2 = 16.2. Hmmm...... it was very sweet!!!
Another night, I was at home having audio system of value, 50, and was listening to the same CD. But, that night my mood indication was 0.5. So, total effect of the music was 50 x (0.5)^2 = 12.5. :scratch: I could not get the same emotion as I had in the car.
Of course, I personally desire both nice audio system and good mood, working together!!! |
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| Sheldon |
janneman: In my book, you do that by trying to neither add nor subtract from the musical signal while it travels trough the sytem. I guess we agree on that, the controversy is about how we check that we accomplish this.
Accurate reproduction? Do we agree on that? "What we have here is a failure to communicate", said in my best fake southern (US) accent, while wearing reflective aviator style sunglasses and holding my state issued prison guard rifle. And just what is it we are trying to communicate? Is it faithfull reproduction of a live performance? That might be feasible (almost) now. Here's my suggestion:
Model a human head and ears (mine, of course, since it's entirely representative of all mankind), and place accurate (absolutely accurate, of course) transducers where the tympanic membrane would be (well, you gotta pick somewhere) and place it in the venue (don't ask me annoying questions like; "which section, which row, what am I wearing?".) Now record a series of test sounds to cover the entire audible range (I'll let someone else determine what that is), set up the playback chain (electronics, speakers, room, furniture, drapes, temperature, humidity, etc.), put my modeled head in your favourite seating position and play the recording. Then go back and process the recording so that everything matches, including amplitude, phase, reverberation amplitude and delay (for all frequencies), decay, etc. (insert your favorite esoteric parameter here),. This would, of course, require some sort of surround stuff and could violate the prescription of "nothing added or nothing taken away". But as you see, the question is; "added or taken from what, exactly"?.
For studio recordings, I guess "accurate" would be to follow the same procedure but set up my proxy head in the mixing room in front of the monitors.
That's a definition of an accurate reproduction chain (well, my definition, anyway). Would you like it? It would sure be different from what you're listening to now. You wouldn't have the "detail" you get from most current live recordings.
If we don't like this, or it's impractical, we'll have to settle for the specific innaccuracies that we (I anyway) prefer most.
For the record, I agree with Janneman that we're probably there now with amplifiers (assuming, given Sy's caveat, that we are operating them always within their limits of accuracy). And assuming, of course that "there" has the narrow meaning of output exactly mimics input. And, assuming that we're driving ideal impedences (and whatever assumptions, as required). It strikes me as a perfectly reasonable design goal for the amp to be neutral and add our filigrees elswhere. That said, my favorite amps, in my system, are tubed (they have such a nice glow). As always, I reserve the right to practice hypocrisy, whenever it suits me.
Sheldon |
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| SY |
| quote: | | This is all fairly well established if you study the field, and generally it is assumed that it is evolution's answer on dealing effectively and efficiently with the immense amount of info we are constantly bombarded with. |
This is exactly correct. And in the light of evolution, it makes sense- if you don't respond to a pattern, you can be eaten. There's a large evolutionary consequence in this. If you are fooled into reacting to a pattern that's not there, at worst you wasted a little bit of energy responding to a false alarm. So our brains are wonderful in pattern recognition but prone to a certain type of error. |
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| janneman |
As one of my professors once remarked: " Gettin' eaten is generally considered as a bad career move".
Jan Didden |
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| janneman |
| quote: | Originally posted by Sheldon
janneman: In my book, you do that by trying to neither add nor subtract from the musical signal while it travels trough the sytem. I guess we agree on that, the controversy is about how we check that we accomplish this.
Accurate reproduction? Do we agree on that? "What we have here is a failure to communicate", said in my best fake southern (US) accent, while wearing reflective aviator style sunglasses and holding my state issued prison guard rifle. And just what is it we are trying to communicate? Is it faithfull reproduction of a live performance? That might be feasible (almost) now. Here's my suggestion:
Model a human head and ears (mine, of course, since it's entirely representative of all mankind), and place accurate (absolutely accurate, of course) transducers where the tympanic membrane would be (well, you gotta pick somewhere) and place it in the venue (don't ask me annoying questions like; "which section, which row, what am I wearing?".) Now record a series of test sounds to cover the entire audible range (I'll let someone else determine what that is), set up the playback chain (electronics, speakers, room, furniture, drapes, temperature, humidity, etc.), put my modeled head in your favourite seating position and play the recording. Then go back and process the recording so that everything matches, including amplitude, phase, reverberation amplitude and delay (for all frequencies), decay, etc. (insert your favorite esoteric parameter here),. This would, of course, require some sort of surround stuff and could violate the prescription of "nothing added or nothing taken away". But as you see, the question is; "added or taken from what, exactly"?.
For studio recordings, I guess "accurate" would be to follow the same procedure but set up my proxy head in the mixing room in front of the monitors.
That's a definition of an accurate reproduction chain (well, my definition, anyway). Would you like it? It would sure be different from what you're listening to now. You wouldn't have the "detail" you get from most current live recordings.
If we don't like this, or it's impractical, we'll have to settle for the specific innaccuracies that we (I anyway) prefer most.
For the record, I agree with Janneman that we're probably there now with amplifiers (assuming, given Sy's caveat, that we are operating them always within their limits of accuracy). And assuming, of course that "there" has the narrow meaning of output exactly mimics input. And, assuming that we're driving ideal impedences (and whatever assumptions, as required). It strikes me as a perfectly reasonable design goal for the amp to be neutral and add our filigrees elswhere. That said, my favorite amps, in my system, are tubed (they have such a nice glow). As always, I reserve the right to practice hypocrisy, whenever it suits me.
Sheldon |
Sheldon,
Yes, this is all very sensible and I agree to most of it. But the subject of the current debate was whether you can use listeners to measure amp performance. In that context, I defined "faithfull reproduction" as neutral amplification of an input signal. I think that for the present discussion that would be acceptable.
Jan Didden |
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| Sheldon |
| quote: | Originally posted by janneman
Sheldon,
Yes, this is all very sensible and I agree to most of it. But the subject of the current debate was whether you can use listeners to measure amp performance. In that context, I defined "faithfull reproduction" as neutral amplification of an input signal. I think that for the present discussion that would be acceptable.
Jan Didden |
Agreed. The amp is one place in audio where we can (well, most of us anyway) probably agree on the definition and physically measure accuracy (whether or not our current measurements are up to the task, i.e., measuring the right things, I'll leave for others). The post was just a long sinded way of saying it gets messier from there in and from there out and in these debates we don't even have commonly accepted definitions.
Sheldon |
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| sam9 |
"But the subject of the current debate was whether you can use listeners to measure amp performance. "
I recall a comment in an audio mag in the late 70's to early 80's regarding this with respect to speakers. The comment (as best I recall) was adressing the observation that while the big Japanese manufacturer's built pretty good active electronics, they were a bust when it came to loudspeakers. I was pretty much in agreement at the time since when shopping for new speakers, AR, KLH, KEF, Advent, etc (I would include Klipsch and Allison except they were beyond my budget) seemed to occupy a level of performance that Sony, Panasonic, Technics etc were not even close to.
Anyway, the comment in the magazine observed that a key difference in approach was that the Japanese companies used a consumer listening pannel. They paid consumers to sit in a room and comment on which speakers they liked, the the engineers would fiddle with something and have the pannel rate the sound again. In contrast, the US and British companies had Mr. Vilchur, Mr. Klipsch, Mr. Koss and so on who could care less what a consumer pannel thought because they themselves damn well **knew** what was right.
I'm not sure if this relates to amps, but if subjective listening can work for amp design, it may be critical to consider who is listening. In any case, I just can't envision a Pass, Curl, Carver or even a Self, Slone or Elliot letting a consumer pannel advise them on their amp design. |
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| janneman |
Sam9,
I just read exactly that in an issue of Multi Media Manufacturer (may/june 2004), from Larry Klein recounting his 45-year experience of audio and electronics. He felt that at the time Japanese manufacturers thought speakers needed to be designed to taste. They did large-scale scored listening tests using assembly line people, maintenance men, clerks, a "carefully selected listener cross section". Their resulting speakers sounded awfull.
Jan Didden |
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| 405man |
There seems little surprise that these are audible differences between loudspeakers. The measured performance of different loudspeakers vary greatly with harmonic distortion in the range of < 0.1% – >5 % and wide variations in frequency response. With in this context the differences between amplifiers is minute.
Stuart |
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| johnnyx |
One thing puzzles me; If you can hear differences between amplifiers, and judge which sounds better, why is it so difficult to set up a loudspeaker crossover by ear alone?:xeye:
You know what sounds "right", right?, so why do we need to measure for something that has a far greater influence on the sound than , say, the type of cap used in the feedback loop? |
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| janneman |
| quote: | Originally posted by johnnyx
One thing puzzles me; If you can hear differences between amplifiers, and judge which sounds better, [snip] |
...but can you? Why are you so sure about that? Do they actually sound different, or do you perceive one as being different. If you do, where is that perception based on? Sound, knowing the brand, seeing the amp, the story from your buddy about this great amp, the effort you had to make to get one of your own, all of the above? Why is it that blind tests mostly fail to substantiate these differences? I know, mostly questions, but they are necessary before getting to the answers.
Jan Didden |
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| carlosfm |
| quote: | Originally posted by johnnyx
One thing puzzles me; If you can hear differences between amplifiers, and judge which sounds better, why is it so difficult to set up a loudspeaker crossover by ear alone?:xeye: |
Because the amps are finished products.
The speaker, it seams that you are finishing, or "setting up".:D
Speakers are different.
5 cm out of the right place and they can sound bad.
Differences in the sound produced by different amps can be huge, even a serious blind test should reveal that.
With experienced listeners, otherwise the difference is there and people can't identify it.
BUT different sound just means better for one listener and not necessarilly so for the other one.
That's why audio is subjective. |
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| Mr Evil |
A few years ago I bought a new graphics card for my PC. In the various hardware forums I frequented at the time there were plenty of people offering opinions on this card. One of the most notable ones was that 2D image quality was superior. On installing the card the image was indeed superior; it was brighter, more vibrant.
Some time later I was faced with the opportunity of comparing it with my old card side-by-side on identical monitors. What did I see? There was absolutely no perceivable difference between them! I would consider myself to be as objective as the next person, but still I fell foul of purely psychological effects of perception.
This effect makes it very hard for any normal subjective measurement to be taken at face value. It's not possible to compare two sound sources by listening to them both simultaneously of course, so the only way to eliminate it is with double-blind testing, which seems unfortunately rare.
Of course if something subjectively sounds bad despite good objective measurements then it is reasonable to consider the subjective measurements as very important, but if they aren't double-blind then I would consider them suspect. |
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| johnnyx |
| quote: | Originally posted by janneman
...but can you? Why are you so sure about that? Do they actually sound different, or do you perceive one as being different.
Jan Didden |
I was asking the question to other forum posters. I haven't compared the sound of different amplifiers, but I have compared CD players when I was buying a replacement. One sounded worse than my present one and one sounded better. I could only tell when there was only a few seconds between hearing each one, because differences get lost in the mists of time.
| quote: | Originally posted by carlosfm
Because the amps are finished products.
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None of my amps are finished products:D
It's difficult because I have been building active systems, I asked the question because of the difficulty of setting up the crossover slopes, frequencies, etc by ear, so I have to use a CAD measuring system to help.
Yet this thread is about (as I understand it) differences in amplifiers which cannot be measured. I just find it strange.:xeye: |
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| janneman |
| quote: | Originally posted by johnnyx
I was asking the question to other forum posters. [snip] |
Huh? Maybe next time you say: "Question for the other posters except janneman":o
Saves us all some time...
Jan Didden |
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| SY |
| quote: | | I was asking the question to other forum posters. I haven't compared the sound of different amplifiers, but I have compared CD players when I was buying a replacement. One sounded worse than my present one and one sounded better. I could only tell when there was only a few seconds between hearing each one, because differences get lost in the mists of time. |
Two interesting points here- first, this sounds like a classic case of a demo being set up without proper level-matching. That may or may not be true, I'm making an assumption, but so many audio legends sart out with just that sort of uncontrolled variable.
Second, your point about delay is startlingly pertinent. Claims about long-term sensory tests have not stood up to the data- we seem, in all of our sensory inputs, not just music-listening, to be most sensitive to differences when we can make comparisons with a minimum of delay. This is just as true for wine-tasting, haptics, and color-matching as it is for music-listening. I mean, if you were asked to compare the weights of two objects that differed by a few percent, what's more accurate, holding one in your hand, then switching to the other, or holding one in you hand all day one day, then holding the other in your hand all day the next day? |
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| johnnyx |
| quote: | Originally posted by janneman
Huh? Maybe next time you say: "Question for the other posters except janneman":o
Saves us all some time...
Jan Didden |
:Ohno: I didn't mean to exclude you, Jan, I meant all others, you included, and not me. If that makes sense.
I was careful that the CD player differences weren't due to a level difference. They were cheap players, using different DACs, and differed in distortion. This was audible when played side by side.
Try looking at one side of a "spot the difference " cartoon, the following day look at the other side. How many differences can you spot now?:D |
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| SY |
| quote: | | I was careful that the CD player differences weren't due to a level difference. |
How did you do this? Level matching to the degree necessary to prevent contamination of the test is VERY tricky. And what makes it insidious is that a tiny level difference (like 0.1 dB) will not be audible to a good ear as a level difference, but rather as a quality difference. A test disc, a multimeter, and the CD player volume control are NOT sufficient to do proper level-matching.
Your cartoon analogy is great. May I steal it? |
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| carlosfm |
Level matching is critical for inexperienced listeners.
It's not so critical if you have experience in making comparisons and evaluating systems, cdps, amps, whatever.
You need to listen to the tune and not the gear.
You need to understand the music, follow every instrument and the whole.
The device where you find more difficult to understand the music and what every musician is playing is inferior.
Basically, what I'm saying is expressed very well here:
http://www.linn.co.uk/buy_linn/how_...ge_a_system.cfm
I find this simple method quite efficient for evaluating and detecting differences.
With this method, sometimes you detect an instrument that was maskerated and unrecognizable on the other gear (amp or whatever).
One of the secrets is to pick just 30~40 seconds of a music and no more. Concentrate on that part.
Change the gear and listen again.
But concentrate on the music.
You will memorize more easily.
I can tell you a little secret: an excellent track to test a system is on Jeff Buckley's 'Grace' cd, track 6 - 'Hallelujah'.
Listen to that track with two different cdps, follow the music.
Stop a while after the guy begins to sing.
Repeat the test.
Concentrate.
How many instruments are there on that music?
Only a good cdp will make it clear!:o
And I'm talking of a not so good recording.
But listen to the music!:cool: |
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| johnnyx |
| quote: | Originally posted by SY
How did you do this?
Not scientific, I know, but I changed the levels so that first one was louder, then the other. The difference that didn't change with level was the difference I described. I looked inside at the DAC and associated components, and looked at the output with a scope, playing a test disc. The worst had a 2x oversampling filter, and sounded bright to me, irrespective of level. The best used a Philips bitstream DAC, and sounded clearer than my Sony one, which had a Sanyo multibit DAC. My wife agreed with the results of the listening test, and I (we) listened before I looked inside. We don't always agree.
Your cartoon analogy is great. May I steal it? |
Feel free!:D |
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| diy_audio_fo |
| quote: | Originally posted by SY
A test disc, a multimeter, and the CD player volume control are NOT sufficient to do proper level-matching.
|
Can you elaborate a little bit your statement, please?
Do you refer to the lack of resolution of the CD player volume control or precision/reading resolution of a commonly available multimeter?
Thanx |
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| SY |
Resolution of the volume control is a big part of it. So is backlash and drift. Normally, to get a level match better than 0.1dB between sources, you have to either use a precision attenuator or an accurately trimmed voltage divider. Either way, it's tedious and a real hassle. But if you don't do that, you're not making any kind of valid comparison, you're just fooling around; tiny level differences are NOT perceived as such by our ear-brain system.
Now, I understand that there's a lot of fun-value and enjoyment in just fooling around, but it doesn't get you to any kind of real understanding. |
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| jcx |
I believe I’ve seen the claim that double blind testing can resolve 0.1 dB level differences that exceed an octave in frequency range – so a full frequency response comparison is the only “sound” approach
Today a full frequency response comparison isn’t as daunting as it might seem, almost any PC soundcard will have the resolution (and probably the stability/repeatability) to make the comparison with freeware spectrum analysis sw such as RMA |
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| analog_sa |
| quote: | | Level matching is critical for inexperienced listeners. |
We have never been in more agreement :).
I also don't understand the obsession with level matching. If it's anywhere within 5db it's fine with me. And no, louder is really not necessarily better. |
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| Peter Daniel |
I understand level matching is critical when one does A/B switching playing music continuously. I also agree that's the way for inexperience listeners.
However, I never do evaluation in that way. I rely on my memory of the presentation and I can easily decide which one is better and why (for me of course). In that case I have never found level matching critical. |
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| SY |
| quote: | | I also don't understand the obsession with level matching. |
This is explained quite clearly in the literature, especilly in the work of Lipshitz and Vanderkooy; it is well-established that minor relative level differences are not perceived by humans as level differences. That's true whether the humans are experienced or inexperienced, members of the "engineering community" or some other occupation.
Now, this is very different that talking about absolute levels; listeners should be able to vary them at will. But the relative levels of the two DUTs must be tightly matched. And again, we're not talking about preference, we're talking about ability to distinguish one DUT from another. |
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| Peter Daniel |
| quote: | Originally posted by SY
we're talking about ability to distinguish one DUT from another. |
I usually distinguish them by size, shape and color;) |
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| SY |
| quote: | Originally posted by Peter Daniel
I usually distinguish them by size, shape and color;) |
Well, that IS the most common approach! |
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| janneman |
| quote: | Originally posted by Peter Daniel
I understand level matching is critical when one does A/B switching playing music continuously. I also agree that's the way for inexperience listeners.
However, I never do evaluation in that way. I rely on my memory of the presentation and I can easily decide which one is better and why (for me of course). In that case I have never found level matching critical. |
Peter,
Please don't take this personally, but as SY stated, it is quite established that even minor level differences are not perceived as such. They are instead perceived as qualitative differences. That means, if you don't match levels, you may quite perceive qualitative differences which lead to preferences which are based in fact on just plain level differences.
Now, I understand that that is very difficult to accept. After all, you CLEARLY hear a difference in quality, or let's say preference. But you must grow to the next higher level of understanding perception and understanding your own mental and sensory makeup and how this puts up a perceptive landscape in your mind.
Until that time, your preferences may be based on something that disappears when the situation is slightly modified. If, as can be the case, you preference is based on slight level differences in a comparison with another amp, than what is it worth really?
Jan Didden |
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| Sheldon |
| quote: | Originally posted by SY
There's some interesting semantics wrapped up in this- if you are "listening" to an amplifier, your brain is going through a very different dance than if you're "listening" to music. In the former case, you're trying to find patterns whether they're there or not. And, whether they're there or not, you're likely to find them. |
This, like the level issues relates to modes of human perception that can lead us astray, unless we are fully aware of them and compensate properly. It's a very interesting subject and it's nice to see such discussions. I have a more mundane question regarding tje test subject hearing (perceiving?) differences in amplifiers that do not correlate with the usual instrument tests; could some of that be due to the fact that the instrument tests are done with simple resistive loads (I don't know how they are actually done), while listening tests are necessarily done with reactive loads?
Sheldon |
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| SY |
| It's certainly possible to do incomplete or otherwise flawed measurements and then not see a correlation with controlled listening tests. At minimum, a measurement suite has to test the amplifier under loads for which it is intended to be used. |
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| johnnyx |
| quote: | Originally posted by Sheldon
I have a more mundane question regarding tje test subject hearing (perceiving?) differences in amplifiers that do not correlate with the usual instrument tests; could some of that be due to the fact that the instrument tests are done with simple resistive loads (I don't know how they are actually done), while listening tests are necessarily done with reactive loads?
Sheldon |
Doug Self measured the distortion of his amplifier with a loudspeaker load. The high - frequency distortion reduced compared to a resistive load, because the impedence increased due to coil inductance, and distortion reduces as load impedence increases. I intend to try this myself.
I take your points regarding level differences. So those CD players could actually sound the same, and two tuners which I thought sounded the same except that one was louder than the other, were actually different.:bigeyes: |
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| FrankWW |
| quote: | | He felt that at the time Japanese manufacturers thought speakers needed to be designed to taste. They did large-scale scored listening tests using assembly line people, maintenance men, clerks, a "carefully selected listener cross section". Their resulting speakers sounded awfull. |
I think asking consumers what they think about the product is a good idea but how the questions get asked, and what they are, is awfully important. Otherwise, we get results like those Japanese had.
Before we do so,we have to examine our assumptions and what we already know.
The division between "objectivists" and "subjectivists" is illegiitimate, in my view, because people can hear reproduced sound they don't like or get tired of very quickly. They can't describe, usually, what's wrong about the sound but they dislike it.
Some research suggests that whats's wrong with reproduced sound folk generally don't like involves parameters the audio industry and audio researchers haven't generally examined in a rigorous fashion, and those are the correlations between distortion products and human perception.
Read, for instance, the work done by Earl Geddes and Lydia Lee:
http://www.gedlee.com/distortion_perception.htm
Look particularly at the AES and SAE presentation and the results.
A small experiment we could undertake for ourselves to subjectively examine the masking effect is to take a reasonably flat audio system and and play around with equalization between 2 and 5 kHz while playing big orchestral music at realistic levels. A bit of a dip in the reponse, particularly @ 4000 Hz, makes for for a for more musical experience because our sensitivity to these frequencies is greater - the BBC fell on this years ago.
The Fletcher Munsen curves tell us either our total system response should follow, or that the recording systems should follow, the general shape of the F-M curves.
http://www2.sfu.ca/sonic-studio/han...s_Contours.html |
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| Peter Daniel |
| quote: | Originally posted by janneman
Until that time, your preferences may be based on something that disappears when the situation is slightly modified. If, as can be the case, you preference is based on slight level differences in a comparison with another amp, than what is it worth really?
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It would be very nice if you could adjust your preferences by changing volume level. Let's say a piece of equipment sucks at 1/4 turn of the knob, but incresing volume 2 notches up cures the problem. Unfortunately, if something sucks, it sucks no matter what the level is.
I am not talking about immediate comparisons, as I don't even bother. I prefer to move to the next level of using my perception: listening to the sound and comparing it with the reference in my head: my image and the memory of the live acoustic sound. When I say original acoustic sound, I'm talking about my perception or image of that sound. In this context, it greatly depends on my taste and senses, which are the result of my musical experience. |
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| janneman |
Peter,
There is NO memory in your head. What happens is that your brain tries to re-create the neuronal connectivity between your various "maps" in the brain to get as close as possible to the connectivity that existed when you did the original listening. At a certain point, the brain signals: yes, this is it, this is how it was at that time, so this is how it sounded. Needless to say, it is inaccurate in the extreme. Relying on this kind of 'memory' to judge differences between equipment is a quite futile untertaking.
Let me try to give an exampole from visual perception. If I look out of my window, I see a few nice trees in the sun. Now suppose tomorrow, when I come back again, someone asks me: are those trees still there, and are they the same ones you saw yesterday? I would look and probably say yes, they are still there, they look like they are the same trees. But suppose someone had come by this night and clipped a few branches here and there, ripped off a bunch of leaves, etc. Do you think I would notice? Surely not, unless it was a significant change, because that was not in the detail that was stored in my memory system.
It is similar with sound perception. Subtle differences between say amplifiers are at the level of 'leaves' and for the life of you there's no way you can remember that even after a relative short time. And the visual system is vastly better in this respect than the auditory system.
Jan Didden |
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| janneman |
| quote: | Originally posted by FrankWW
I think asking consumers what they think about the product is a good idea but how the questions get asked, and what they are, is awfully important. Otherwise, we get results like those Japanese had.[snip] |
As I recall the article, what the Japanese manufacturer did was asking people to indicate their preference order for several speakers. These preferences were tabulated by a computer to get at an overall ranking.
Remember these are Joe and Jane Listener. If you go to more structured tests, asking specific questions aimed at getting to the differences between speakers, you are already gyrating towards a 'scientific' or 'objective' test.
Some people tell me I shouldn't use measurements or scientific tests because I don't know what to measure to correlate with sound quality. Now we see that using listeners to develop a product leads nowhere. So, what should I do next??
Jan Didden |
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| carlosfm |
This discussion reminds me the old thread "blind listening tests and amps"... and it didn't end well, because there are several approaches to this.
In my oppinion and in my experience, independent on the volume, I can detect subtle details from one cdp to another one, independent on the volume setting.
It would be good that a bad cdp would match a good one just playing louder.
The fact is, with the better source or amp or whatever I listen more things, I listen clearly each instrument, I can detect sounds that were not perceptible.
And I like to play with the volume , I don't like that someone adjusts the volume level to a fixed setting at his will, I like to be free to listen as I like.
Don't take me wrong, but that method is for a pure A/B test, made for inexperienced listeners.
Switching back and forth doesn't let you concentrate on the music, and it's clearly not the best way to evaluate a system.
I'm sorry, I just have a different oppinion, I just hope this thread doesn't end like the other one.:angel: |
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| jh6you |
| quote: | | Originally posted by janneman |
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