[B] NEED HELP - Diganosing audio differences between source components [/B] - Page 6

It is? Here is a quote from it:

"He said: "If you go to [major player in the hi-fi industry; name removed] to buy a 50 watts per channel amplifier - bearing in mind that you would need 500 watt peaks for most modern recordings at normal listening levels - you would be asked to pay around £750. A CD player could be £850. If you want a radio then that's more money, and if you wanted a pair of speakers that could be an additional £850.

So for £3,000 you've got a pretty mediocre system..."

So you need 500 watts for amplification? And this is a mediocre system? What makes it mediocre?

He is an audio manufacturer. If you go to his company's web site, your read this: http://www.avihifi.co.uk/adm9.html

"ADM9T's comprise a reference quality 24/192 DAC, a remote controlled three input preamplifier with two optical digital and one stereo analogue inputs - an electronic crossover and two power amplifiers (75 WPC for the tweeter and 250WPC for the bass drivers). This makes them unique in being a complete hi-fi system in a pair of stand, wall or shelf mounted speakers. All they need is zeros and ones. i.e. anything with a digital output."

24/192? Is that spot on as far as specs we need to read about? Later in the page it says this about the DAC:

"DAC: Up to 24/96 Stereo with optical S/PDIF."
So now it is 96 and not 192?

And why 250 watts for the bass if you need 500? The man sells integrated economy active speakers so he likes to say don't go and buy separates and spend more money with the other guy.

He may have a good product but lacking any double blind tests of how his speakers are better than the myriad of pro powered speakers or the separates he scuffs at, leaves me with the conclusion that what he is saying in that article is marketing competitive talk. To wit, the only review he links to is a subjective one in a HiFi magazine after he got done telling us they are all corrupt with one exception. Was the exception this one magazine who wrote a good subjective review of his product?

You said you should know where folks are coming from and commercial interest being bad. Still feel good about saying this one was "spot on?"

To be fair, yes, there is a lot of product out there that is sold at outrageous margins and with quality and performance that is not there. But let's have someone else tell us that than this person for heaven's sake .

What kind of performance, audible one?

Absolutely.

How did you find that out? Did it involve using your ears?

Thanks Amirm. I'll try to read it this weekend.


Oh! C'mon Amirm, there's no point in going through Maxwell equations. I think I already aswered this to you. Fick's law, Navier Stokes and Maxwell equations are the specific framework for mass, fluid and electrons transfer that are not necessary to explain simple phenomena usually found in audio science.


I didn't noticed it Mcnarus. Thanks for the warning.


Ok Rutgar. Fair enough.

In any case I wouldn't take audio shows as reference because too much BS is showed there. Perhaps you might be interested in attending some european shows instead. At least european manufacturers are not so prone to spreading BS everywere

Ok. This guy may not have moral authority to show us the rip-off tendency of HiEnd industry, but that does not alter some facts

Do you want to read serious HiFi audio journalism? Avoiiding Stereophile, TAS and some others may be a good start.

Then take a look at some german magazines

I certainly think the guy is right that there isn't enough good science behind a lot of what passes for high-end audio. But his standard for science seems to be that you need to sound sciency. Sort of like Stephen Colbert promotes truthiness.

I believe Amirm is referring to a Hawksford paper which details how jitter noise in the digital stream gets into the analog output. NOT Malcolm's paper on skinning.

j

Perhaps, amir, the crux of the matter is that you seemed as willing to attribute the perceived differences to this technically possible, likely non existant, and assuredly fleetingly subtle physical mechanism as you were to the many more common, thoroughly documented, and vastly more powerful psychoacoustic mechanisms. Occam's razor.

I have no problem with your argument. I believe both the technical aspects and your objection to people sweeping it under the rug when the solution is often free are well justified. If you entered the discussion from the angle of "while this is probably just listener bias or other psychoacoustic effects, there is a physical mechanism that exists, and in some cases may cause subtle audible differences, that is worth remembering since it can be avoided with a cable swap..."

As I've said to dragon before, honey not vinegar...

Thanks JN. I kept scratching my head trying to figure out how Maxwell entered the equation .

Here is Professor Hawksford:http://www.essex.ac.uk/csee/staff/profile.aspx?ID=1486



Professor Malcolm Hawksford BSc PhD Aston, DSc, CEng FIEE FAES FIOA

"Malcolm Hawksford has been active in university research since 1968 and specifically in audio related research since 1976 where he is currently a Professor in the School of Computer Science and Electronic Engineering. Over his career Malcolm's research has embraced both analogue and digital audio systems, including signal processing and loudspeaker technology.....

His research has also encompassed oversampling and noise-shaping techniques applied to analogue-to-digital and digital-to-analogue conversion with a special emphasis on SDM and its application to SACD technology; also the linearisation of PWM encoders, diffuse loudspeaker technology, array loudspeaker systems, and three-dimensional spatial audio and telepresence including scalable multichannel sound reproduction.

Malcolm is a recipient of the AES Publications Award for his paper, "Digital Signal Processing Tools for Loudspeaker Evaluation and Discrete-Time Crossover Design," for the best contribution by an author of any age published in JAES, volumes 45 and 46; and he has been awarded the AES Silver Medal for "major contributions to engineering research in the advancement of audio reproduction".

Malcolm is a Fellow of the Audio Engineering Society, the Institution of Electrical Engineers and the Institute of Acoustics. He has published numerous technical papers and audio articles and has supervised a significant number of research students."

That said, I think he is way short of Maxwell in the facial hair department:

Thanks. John. In fact I thought Amirm was refering to Hawksford paper titled "The Essex Echo" which I read a long time ago. It refers to axiall propagation in cables under the frame of Maxwell equations. Great article BTW.

I'd appreciate if Hawksford paper regarding jitter is available for sharing. Lately I've been too busy comissioning a scrubber here in Santiago Chile and I 've missed these discussions in Avsforum

It doesn't alter the facts including the one that people are uncritical of anything that supports their point of view, but even if the Pope shows up to say they may be wrong, they might accuse him of lying!


Half of that would be terrible advice. If you ignore Stereophile measurements, then what on earth are you hanging your hat on objectively? Just looking at pretty pictures of equipment and saying they are all great? Both Stereophile measurements and Paul Miller's have a solid place in any proper objectivist who wants to base their opinion on facts and data.

This anti-measurement stance on behalf of people here is really, really puzzling to me. I don't know how you can say you are technical, and believe in unbiased data yet want to immediately ignore anything to do with measurements. I mean Stereophile is the closest thing to bible of measurements we have that is available to all. I find awful amount of useful information in looking at them. Sure, I ignore the subjective words that come before it. But the measurements are amazingly useful. And a great learning tool to compare one design to another.

Agree on TAS though for the most part. There is data sometimes on products though such as who built it, the theory behind it, that I find useful. I have read about room EQ products for example there that was never reviewed elsewhere. As per Stereophile reviews, I ignore the subjective writing there.

So please don't throw the baby with the bath water because of the title of the book. Let the information come from wherever it comes. Just because a headline sounds good to you doesn't mean you should believe what is there per article we are discussing. And don't throw out magazines with good data in them because you don't know what the editor writes otherwise. Be an educated customer and find what is useful information.

Amirm, where did you get the idea I'm an anti-measurement guy? Another of your rotten debating tactits?

Stereophile the closest to the bible? Are you serious about this? Now I'm wondering about the origins of your Stereophile paraphilia...

That's why I recommended to take a look at some european audio magazines, mainly german. You can start with Stereoplay Amirm

In any case, If I'm in the mood or interested enough in some technical subject I always go to first hand technical sources. If they are peer reviewed, it's better for me. That's how you get serious about the technical thing Amirm.

Now and then I read some technical stuff about audio, but once you told me there's no rigour at all in audio world Amirm. I mean, technical papers are not peer reviewed. Then I lost most of my interest.

Regarding TAS... The reviewers and collaborators are... well, it's a pity.

Take a look at TAS recent page and then an old Sound and Vision page:

Huge differences, don't you think?

It was hard to conclude anything else when you dismiss Stereophile despite practically every review being accompanied with a set of measurements.


Yes I am serious. It is in English for those of us who only speak that and all the data is given away without registering.


I have been there a couple of times but find machine translation not effective since they put their tally in a graph which doesn't get translated. And at any rate, I like to see the raw measurements not bar graphs summaries. Maybe I have missed what is attractive to you there. Do you have a link to a page that shows this kind of DAC measurement? http://www.stereophile.com/content/r...r-measurements. And oh, they review gear that is available in this country.


That's a shame. There is a lot to be learned without that seal of approval from someone else.

It is a well written article if one considers the venue, the style, and the fact that the readers will be unable to critically evaluate the technical content.

Unfortunately, it is a technically abysmal analysis, full of conceptual errors which completely trash the conclusions. It is unfortunate that it still exists out there, sullying Malcolm's name.

1. He assumed planar wave propagation into the conductor, and assumed anything that penetrates comes back out. It doesn't...it dissipates.

2. He ignored the internal 15 nH per foot inductance of a cylindrical conductor.

3. He actually used steel wire for his test, I was informed (during e-mails with him) that his steel wire had a magnetic permeability of about 100, but yet in the test setup he ignored the consequences of a 100 fold increase in internal inductance (from 15 nH per foot to 1.5 uH per foot per conductor, or 3 uH per foot).

4. He tested a shorted run of wire, which is as low impedance as you can get. At high current slew rates, low impedance circuits have higher errors due to inductive parasitics..those were ignored.

So the paper is shall we say, rather inaccurate..

I have read some of his dsp work.. What I was able to understand was entirely internally consistent, and externally consistent with what I know.

In my opinion, he is above reproach when it comes to DSP. He's a bear, an 800 lb gorilla.

j

Hi John. This is news to me. I read the paper 6 or 8 years ago and it should be in some of my old archives in my PC at home.

I don't have Hawksford paper about dps and jitter but I'd certainly like to read it.

And that my friend has something to do with reality. There are few people in this world who have done careful listening tests of as many different amps, CD players, even vinyl setups as my audio club has over the years. What we found is that once you deal with the obvious distractions like mismatched levels, unsynched recordings, and sighted bias, audible differences between audio gear happens a lot less often than is reported by our less careful friends.


There is a right way to support that claim. It would be all about equally careful testing done by someone else that shows a different result. Got any?


Oh, they've started doing careful (blind, level matched, time synched) listening tests at the RMAF? Say friend, here is their web site: http://audiofest.net/2012/index.php
Where might I find information on the RMAF site about their change-over from random demos that prove very little, into doing proper listening tests with the controls that virtually every scientist working in this area agrees must be use?

^^^

All I can say to you Arnie, is that if all of your methods of testing have shown all gear sounds the same, then your methods are most obviously very flawed.

What if I came out and said it was due to placebo, lack of competence, and poor methodology that you found any differences you did? How does that sit with you Arny?


I thought you just said you and your club had found differences per above. Yet here you make it sound like it is an impossibility. So I guess we should not accept the above statement that you had found any differences at all . Do you have the tests that found differences documented anywhere we can read?

Complaining doesn't contribute anything on this forum.
Do you have anything useful to say about audio related subjects?

For more discussion of the Hawksford "Essex Echo" article, see this Audio Critic issue (in the "hip boots" section ).

Pointing out someone's flawed testing method is extremely useful, and not a complaint.

Maybe you shouldn't be posting on audio forums while intoxicated.

amirm, your continual attempt to discredit and disrupt arnyk confirms once again how effective arnyk's debunking of your marketing in disguise was: http://www.avsforum.com/avs-vb/showt...2#post20255022

I must have missed where you pointed out the flaws in the testing method. You simply made a general statement with no specifics.

Can you share your process for determining that different components DO have audible differences? Something beyond what you believe you hear?

Rutgar, here's something you can respond to if you care to contribute (which was to your claim "And I have three cd/sacd players... and they all sound different. So there you go."):

= results of your test does not fit into my pre-conceived expections, so they must be wrong.

then why even do the tests?

Discredit? You mean if I ask someone who has said they have found differences in audio equipment to post their tests here, something is wrong with that request? Can you please explain why that would be?

You mean why did I reply, "amirm, your continual attempt to discredit and disrupt arnyk confirms once again how effective arnyk's debunking of your marketing in disguise was: http://www.avsforum.com/avs-vb/showt...2#post20255022" to this post?:

Try reading again.

Knock it off guys...

Where do you get the idea that "All of your methods of testing have shown all gear sounds the same".

What I said was:

"Audible differences between audio gear happens a lot less often than is reported by our less careful friends"