Accuracy Part 3.

Here we go round the anal bush

 

I think you can get special razors for those these days.

 

See the rest of my original sentance...

Yes, those and Harry F. Olsen's Acoustical Engineering I even recommed Everest's book (see here):

http://www.zerogain.com/forum/showpost.php?p=46291&postcount=7

Zwicker, E & H. Fastl "Psychoacoustics: Facts and Models"
Blauert, Jens, "Spatial Hearing; The Psychophysics of Human Sound Localization"

There are some good papers in the AES and IEEE that I can give you pointers to, but you'll need digital library membership or $$ to get them online.

As you ask, I've read the books I've cited - which are the "standard reference" - along with others too, and quite a large pile of research papers.

FWIW: Folks don't need to read the mountain, just to be aware of it's most important results, and accept that the ear is considerably less sensitive than electronic test tools. People seem to readily beleive that the ear can hear things that can't be measured and this simply isn't true (as shown by all that research..)

Ivor's great at marketing

Harman owns Revel and Infinity: The Salon's, the Gems and the M20's are not easily dismissed, and the Infinity MTS Prelude is quite a speaker too.

HK's next receiver, the 635, is rumoured to be a poor mans Lexicon MC12v4 - if that is even remotely true, it will be hugely successful, and probably measure very well too

 

Here you go, Sony DVP-NC685V :

http://www.soundandvisionmag.com/assets/download/SonyDVP-NC665extendedlab.pdf

From the article:

The audio emerged in near pristine condition. Noise levels for Dolby Digital, CD, and SACD were extremely low (right at the theoretical limit for CDs) and some of the best we've ever measured at any price level.

Seeing as it's a DVD/SACD autochanger too, upping the budget to $250 seems quite reasonable, although street price is probably closer to $200

 

bet it sounds shit though.
cheers


julian

 

That remark vindicates what I've been saying about bias: your making decisions about the sound quality of a player based on factors other than the actual sound.

 

Thanks for the recommendations. I love books.

Provided of course that all audible parameters of the components measure the same. Can we always be sure that all audible parameters are measured?

In the field of loudspeakers we can't measure all the significant parameters and display them in a meaningful way, particularly those parameters that relate to dispersion characteristics and their relationship to ambient sound. This is why there have been so many vastly different approaches to these issues, ranging from the Bose 901 to the new B & O Beolab 5 and "Layered Sound" (which is my current field of exploration).

 

no i'm expressing an opinion about what it might sound like. having not actually heard it (and i'm unlikely to as i thing sacd a waste of time and i don;t need a nautochanger) it seems a pretty pointless exercise. this is the point of MY posts. that the measurements in isolation mean squat when you add the remainder of the room / system / listener into the eqauation - especially that last one.
it's like talking about the top speed of an engine without considering the gearbox, diffs, aerodynamics, driver, etc.
the practical and human elements will always make measurements a poor way of evaluating hi-fi.
cheers


julian

 

We seem to do a reasonable job of measuring the sound field for the recordings that people like to wax lyrical about, and that simply requires a pressure sensor

Floyd Toole, has a 72 point anechoic measurement system, which measures around the speaker, and captures some of the dispersion charcteristic. He also has a computer simulation which takes that data and calculates what it will meaure like in a room. And having hugely expensive test facilities to play with, they even measure the speaker in a real room and get a fair correspondence of measured and simulated in room response, validating their simulation technique. Anyone with $20M or so for R&D could do it!

There are just so many interesting speakers, which have vastly different in room responses, that it's just not worth wasting time (or money) agonizing over +/- 0.1dB variations in CD players. It's why I think it makes perfect sense to spend $250 on a sony CD player and to put as much money as possible into the speakers...

 

And of course you are perfectly correct, +/-0.1dB variations in cdp isn't worth the effort.

But what about all of the other thing which aren't shown on the Sony specs, jitter, spectral analysis of dither, intermodulation, sinewave accuracy. If you are following the 'if they measure the same hey sound the same' dictum then make sure everything is measured.

 

Those things are in the distortion and noise measurements which are given.

 

Ok, maybe I should have said that I would like to see the plots of spectral analysis of dither, intermodulation, sinewave accuracy and what is the jitter measurement. Something like those done by Stereophile.

Here is a link to the measurements of an Arcam FMJ CD33, and if I interpret what you have given vs the Arcam, the Arcam kills the Sony, or should I say measures differently and in most cases with lower distortion and therefore will sound better.
http://stereophile.com/digitalsourcereviews/704arcam/index4.html

 

Could explain the relevance of those particular measurements and why are total noise and distortion insufficient?

You can say "kills" if you can clearly demonstrate that that is the case

But would you concede that the levels of noise and distortion are, for either the sony or arcam, very, very low. And will be completely and utterly irrelevant when compared to the noise and distortion of the loudspeaker/room.

But to make that final clause of your argument, you have to show that the ear is capable of detecting these very small levels of distortion. You cannot simply assert that this is so. You appear to have fallen into the trap of asserting that "what can be measured can be heard".

Stereophile have careful chosen their measurements, of remarkably tiny (in the measurement sense) differences, in order to focus a giant magnifying glass on them, but they have skated over the audible significance of these measurements and left it to the audience to conclude, incorrectly, that the measurements must be audible. It's a cynical manipulation of the audience by Stereophile.

Just what is the relevance of a -90.31dbFS undithered signal? Why they are using that particular combination, and do you know what figure 5 should look like? If you do, you might be "horrified" by what fig 5 actually looks like

 

But using your own argument, the less the distortion the better the accuracy.
Therefore the inference is that the Arcam will be more accurate than the Sony.
Also using your own argument because they don't measure the same they won't sound the same.
Therefore the inference is that the Arcam will sound better than the Sony.

 

oedipus,
what exaclty is you aim with this argument? do you have a warehouse of sony multichangers that you are trying to shift or do you just enjoy pissing on others chips (but missing and hitting your own shoes instead). perhaps you see your role in life as educating those you condescendingly see as somehow less than yourself or are you just an argumentative type? plainly you are pissing in the wind on this one mate there is a reason that some here choose to listen to their hi-fi rather than read about them and then hook them up to arcane bits of measuring equipment i'll leave it an an excersise for you to figure out why.
cheers

julian

 

And doesn't this make the whole thread a waste of time? You have been insisting that the lower the distortion the more accurate the sound. Measure the output of a null test and the lower the level the more accurate the system. So on one hand you want us to measure something to validate that we are hearing something, but in the above your are now saying that we can't hear everything we can measure.
Does this also mean we can hear things we can't measure (yet)?

 

That wasn't oedipus's argument actually - it was IIRC if they measure the same, they sound the same, which obviously isn't the same thing (can't be bothered to go through the thread and check so if I'm wrong correct me ). The measurement differences you're talking about are minute and way below the subjectively audible levels - read a few more Stereophile reviews and they do even acknowledge themselves from time to time that the deviations from ideal performance for most of the CD players they review are not remotely significant.

 

It's only worth engineering the distortion to below the level at which it is audible.

Both players have inaudible levels of distortion.

The difference in distortion is below the level of audibility so it won't be heard.

The Ear will not be able to tell them apart.

You cannot draw that conclusion from the two things that I have been saying.

I have argued that two products that measure the same, sound the same, and that there is no "magic".

I have also argued that for CD players we can formulate an objective definition of accurate.

You are the one falling into the trap that if one measures more accurately than another then that measurable difference must be audible.

The measured electrical accuracy is only part of the story.

For some gross differences in the measurements, the "Wadia curve" for example, is both audible and measurable and the audible difference is explained by the measurement. Again, no magic.

For small differences in measured performance, like we are talking about here, the subjectivists need to provide evidence that they can hear those minor differences - in a properly controlled double blind test. OR you need to show that the measurements you quoted are above the threshold of audibilty and can reasonably be claimed to be heard.

So, you need to take the measurements AND what is known about human hearing (of distortion) to be able to claim that the differences are audible. The onus is now on you to show "that the ear is capable of detecting these very small levels of distortion" OR otherwise, accept that from the standpoint of human hearing, the players to all intents and purposes measure the SAME.

This is true. I have always said that, in the Ohm's acoustic Law thread for instance.

No.

Where your side of the argument falls down is that you assert that you can hear things (eg. minor differences in distortion) but you are unable to demonstrate this ability in a properly conducted test, or provide any previously gathered, verified, scientific evidence to support your claim.

 

What is the audible level of distortion? I've been trying to google for this but can't find anything.

I've obviously missed the definition, could you repeat it?

I thought I had been careful and used accurate, whose meaning I still don't understand.

No they don't measure the same. The measurements show that they don't. They may sound the same or they may sound different, but the measurements won't show this.

 

This is the one I really want a reply to

So what is the rest of the story if it isn't measurement?