Accuracy Part 3.

I'd like to ask you how the manufacturer is able to test whether the product is working properly, if he is unable to measure it with conventional test instruments?

Are you saying that all audiophile products must be test by human ear, presumably a golden ear, before leaving the factory? Was your CD player tested in this way? Do you have a certificate to show that the tester was in good health, with good hearing, and not suffering from listener fatigue or a cold on the day your CD player was made?

If you agree that conventional electrical measurements tell all, then we can go down that path, otherwise you need to address the conundrum presented in the second paragraph.

 

All of my products are designed and tested by measurement and by ear. Of the two, human hearing is by far the best indicator of whether a product is good or not.

After the design is fixed, simple measurements are sufficient to ensure that standards are maintained.

Julian is absolutely right when he talks of the millions of years of evolution that ensure that human hearing is by far the best indicator of good hi-fi. One day, measurement could well be all that is needed but on that day we will be measuring the right parameters and there will be a much closer correlation between 'measurement accuracy' and 'musicality' than there is at present.

To those who believe that current measurements (or null tests) can indicate the degree of accuracy and therefore determine how good a product is, I'd like to ask:

How do you know that the equipment that measures 'most accurately' sounds the best? How do you judge it?

 

So, you are saying that for quality control purposes, the correct functioning of an audio product can be revealed by conventional measurement techniques? And that (therefore) two items that measure the same, sound the same?

 

yet again a very good question is ignored and answered by another question

How about this question being the starting point for the rest of this thread?

 

I "ignored" it because I've already answered that question earlier in this thread here:

http://www.zerogain.com/forum/showpost.php?p=96183&postcount=79

Start another thread on that topic if you feel like. Here we're working towards why $100 cd players are as accurate as $5K players...

 

indeed you are,except ears baren't included,and i can't find anything in that link that answers Steves question

 

No you are using semantics to deflect the discussion rather than measurements.

In Mathematics when somebody states they have solved something, they don't then say "And prove I haven't", they have to publish proof that they have. You made the statement about $100 cdp, now I am waiting for the proof.

 

No, I am asking you to assist me in the construction of the proof and it's why I asked these questions:

So, what are your answers? [If you look at my reply to 7_V, you should be able to work out where this is headed ]

 

The Kindergarten, I imagine

 

I'm saying that if two audio products use the same components (drive units, cable, damping, woodwork, etc.) then similar measurements will generally provide a sufficient indication that both products will sound the same.

However, if I changed a component, I would listen to the result (and get others to listen). Measurement would not then suffice.

I do this for a living, oedipus. Mine is a practical approach to producing the best products that I can. If you could imagine yourself in a similarly real (rather than theoretical) situation, perhaps you wouldn't ask such a 'clever' question.

However, now I've given you an answer, please humour me by answering my question:

How do you know that the equipment that measures 'most accurately' sounds the best? How do you judge it?

 

why steve, subjectively by ear of course... unless you are listening to the sound of silence from your beautifully perfect null testing system.

this is the problem with some people - cleverness can equate to myopia.
cheers


julian

 

For clarification (I have only read about 80% of this thread, so forgive me if you already gave this info), are you talking about the 100$ CD player as a source of digital data to feed your Tact with, or about a stand-alone 100$ CD player supplying an analog preamp?

 

You've dragged us into an unnecessary "subjective" debate, you'll notice that the discussion was about CD players where there is a defintion of accurate: are the amplitudes at the analog outputs an analog of the bits encoded on the disc. It doesn't really matter how the player accomplishes this feat. We can measure the exactness of the recreation in terms of frequency response and THD+N. A player with a flatter frequency reponse, lower distortion and lower noise is technically more accurate than one with worse measurements.

Now, there is no mystery to red book CD, we can calculate theoretically its maximum performance. Lo and behold, the measurements that are published in magazine like Sound&Vision show that cheap DVD players are operating at the limit of theoretical perfection in terms of their measured performance.

The truth that you (an LiloLee and Julian) are trying to escape is that products that measure the same sound the same: even when those products come from different companies.

Now, it is clearly possible to build and expensive product that isn't technically accurate, but what's the point? You're paying money for either a tone control or increased noise or increased distortion (or a combination of all three), and these show up in the measurements. Wadia as I have previously pointed out sound different because they have an incorrect frequency response as can be clearly seen in the measurements (see the stereophile review of the 861.)

What you are trying to get away from is the inescapable conclusion that if two products measure the same, then they sound the same.

Floyd Toole, amongst others, also does this for a living and yet he's answered those questions for himself and published the results for others. He isn't shy of 'clever' questions and doesn't hide behind a whole load of subjective mumbo jumbo, and the company he is head of R&D of (Harman) produces a large number of speakers, using test instruments and measurement techniques that are state of the art - and it comes as no surprise that their products are excellent.

I'd also add that people who do R&D in the area of subjective evaluation are aware of a number of limitations of human hearing, which is a far from a perfect "measurement" instrument (and we only scratched the surface of those imperections in the
Ohm's acoustic law
thread.)

From this it is reasonable to infer that you know little of psycho-acoustics, otherwise you wouldn't be inclined to make this kind of statement, at least not without considerable and lenghty qualification over the problems that using a small sample of listeners can cause.

What continues to amaze me about the Audiophile brigade is just how far into electrical engineering they are prepared to delve and yet nobody seems to pick up a book on psycho-acoustics - a scientific endeavour which has been going for well over 150 years and has mountains of research detailing the limits of human hearing.

 

As far as I'm aware, in most fields of academic research that's very much the norm rather than the exception - in fact I can only think of one journal off the top of my head where the results have to be reproduced independently before a paper is accepted, and suffice it to say that the results published therein are rather more reliably robust than the average.

As you point out though, the academic community is a rather small and bitchy one, and while slightly playing down inconvenient features of your work is pretty much par for the course these days, outright falsification - ie. claiming that something works when in fact substantially it doesn't - is a recipe for disaster for your career.

 

oedipus,
the problem is that you seem to be comparing apples to oranges here i.e. sounding the same and measuring the same.
also you seem to be saying that recovery of the bits from the cd is the end of the story rather than just the beginning.
cheers


julian

 

Why is it 'reasonable to infer that I know little of psycho-acoustics' from my statement above?

You also say:

I didn't say or imply that human hearing was a perfect 'measurement instrument'. Look again at what I have written.

For your information, the classic book which is a must read for many in the field is "Acoustics" by Leo L Beranek (1954). Chapter 13 is entitled "Hearing, Speech Intelligibility, and Psychoacoustic Criteria".

A more modern favourite is F. Alton Everest's "Master Handbook of Acoustics" which has a chapter (3) on "The Ear and The Perception of Sound".

Other than these chapters and various other bits and pieces picked up from the Internet, I haven't read any books specifically on Psychoacoustics, although if you look at the design of the speaker systems on the Seventh Veil website, you will doubtless see that a number of design elements have been shaped by Psychoacoustic theory.

I note that Amazon has a number of books on the subject. If you have read any of these and can recommend them as adding significantly to the information in the sources that I have mentioned above, I will be happy to consider ordering them.

If on the other hand, your own reading on the subject doesn't extend much further than the few words in "High Performance Loudspeakers" by Martin Colloms (which one might guess is the case from your earlier post mentioning 'listening fatigue' and 'colds') then you are unlikely to provide the "Audiophile Brigade" with much guidance on the subject. You talk a good psychoacoustics; how far up the "mountain of reasearch" have you actually climbed?

On the more general point, I personally would be delighted if it were true that inexpensive cdps and amplifiers were as good as the better, more expensive models. It would mean that Audiophiles would spend a much higher proportion of their budget on speakers, which would suit speaker companies fine. A similar 'trick' was pulled off by a certain turntable manufacturer who persuaded large swathes of the industry into a 'source-first' approach that brought him riches beyond my imaginings.

Incidentally, for all their undoubted expertise, I haven't heard anything by Harmon Kardon that particularly impressed, have you?

 

If two components measure the same, then they sound the same. There can be no effect without cause.

We know what bits are written on the disk. We know what signal comes out the analog side. It doesn't matter what goes on in the middle - for all I care, a fairy could be running her finger over the disc and swapping the signal lead amongst a large number of batteries - the only thing that matters is how well the output matches the input. So, it doesn't matter what the story is for what goes on in the middle, that "story" is just hogwash to justify one kind of tweak or expense - all that matters is the output.

 

And so far I haven't been presented any measurements from any cdp, so, so far it is all semantics.

 

oedipus,
you seem to be determined to reduce an emotional experience to numbers. fine, if this floats your boat but personally i'd rather enjoy the music. however you originally said that a $100 cd player would measure and sound the same as a $5k one. as lee says put up or shut up, everythign else is pointless wanking.

cheers


julian.

 

It's the old 'you don't appreciate music' argument again . oedipus hasn't tried to 'reduce an emotional experience to numbers' - he's presenting engineering as a science, not music.