Audible Jitter/amirm vs Ethan Winer

Nicholas Bedworth

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May 7, 2010
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Maui, where else?
Drive us all batty? Are we having fun yet?

@Gary... something about your comment suggests that battiness is a possible condition in the future. There is some evidence that it is already well-established in certain areas :)

My experience trying out several digital interfaces (for months in comse cases) pumping data into the Weiss DAC 202 is that the listening pleasure is inversely proportional to carefully-made jitter measurements. You can sort these interfaces into low, medium, high jitter pretty readily, and secret collaborators (who seem to purchase just about everything that the industry turns out) independently confirm this general assertion, based upon quantitative data from six-figure test jigs.

Low jitter: air, smoothness, action. Listen for hours, even at high volume.
High jitter: hard, dry, cold. Annoying within seconds.
 
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Apr 3, 2010
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I had a redux of this discussion in another thread with Arny Krueger whom some of you might know has having pretty close views to Ethan on this matter. Armed with more data than when this thread was created, the discussion became more detailed although the summary message is exactly the same. As here, I wrote my summation there and thought it might make sense to also post it here. So here we go:

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While we don’t think them as such, I think these debates are like mock trials where there is a prosecutor and defending attorney trying to prove their respective points of view. As with a real trial, it is useful to have a summary statement at the end as to make sure each party’s position is not lost in the all the back and forth. So I am going to do that now and unless there are substantial new points to be made, call it done.

This debate started with Arny calling me “presumptuous” as I declared USB as the way to go in interconnecting audio systems to your computer. Question is, did he succeed in demonstrating that? For that answer we need to think through the architecture of the systems we use. When playing music, we know that we can distill the content into files. We can copy those files on our computers with reckless abandon and even send them across the world over the unreliable and non-real-time Internet and still, unless something goes wrong, get the original back intact. Digital audio in that sense is perfect!

Sadly, when our current interfaces were designed, they were not architected the way they should have been. We take digital data that is nicely marked with its timing and data in a computer file and turn it into a real-time stream across a cable. The source is the “master” telling the destination when to play each and every sample. On paper, the timing is perfect vertical pulses that instantly go from zero to one, and with zero variation. Sampling theory says if we did that, indeed we can have perfect reproduction. That is, if we reproduce the samples at the same time they were captured (digitized), we can reconstruct the signal perfectly.

Alas, real world doesn’t work that way. The above definition of our timing signal is that of a square wave. The wiki on square wave says it nicely: “An ideal square wave requires that the signal changes from the high to the low state cleanly and instantaneously. This is impossible to achieve in real-world systems, as it would require infinite bandwidth.” Let me repeat: you need infinite bandwidth. No cable or interface has infinite bandwidth. So we know what gets to the other side has less than perfect edges. As soon as we modify those waveforms, we also start to mess with the timing that can be extracted at the receiver. Yup, horrors of horrors. Your digital cables can have a sound!

We get confused looking at the low-speed audio signals thinking not much accuracy is needed to represent their timing. Arny made that mistake of thinking 1 microsecond of timing should still be great. That is one millionth of a second. By a person not schooled in the science of digital audio and signal processing, that does look like the right metric relative to CD’s 44,100 samples per second with each sample taking 22 microseconds.

The science unfortunately is not that forgiving. It doesn’t just look at the sampling rate of the audio but more importantly, how much resolution and how low of a noise floor you want to have. We love our digital systems because they are so quiet. A 16-bit system has a range of quietest to loudest signal of 96 decibels. That is the lowest level digital system we use for high-fidelity music. 30+ years after introduction of CD, it sure would be nice to be able to achieve what its specs say on paper, in a real system. Don't you think?

Given the above, and making some significant simplifications, we can compute how much timing change it takes for one of those bits to get corrupted. With each bit representing 6 db of distortion products, the math can be computed as I showed from Julian’s formula. That math says that timing accuracy better be 500 picoseconds or else your system has less resolution than an ideal 16-bit system. A picosecond is one million microseconds! Wow oh wow!!! What have we gotten ourselves into? We need accuracy that is 2000 times smaller than Arny’s one microsecond number.

While not a topic here, but a point I made, the receiver cannot throw out timing variations. Why? Because it really doesn’t know how fast the source is going to send it data. Indeed, sampling rates like 44,100 are “nominal” values. The receiver cannot use them as the source of timing. It is entirely legal and indeed happens all the time that the transmitter will run slower or faster than that rate. The standard allows +-5% variation. So the receiver is tasked with the tough job of throwing out some variations but not others.

Smart designers over the years have figured out good ways to deal with that in S/PDIF domain. In HDMI, they are kind of stuck with off-the-shelf silicon which is first designed for video, and secondary for audio. Clock recovery being a “mixed signal type of problem” involving both analog and digital, means that there are far more engineers who get it wrong than right. I know. I have had the unhappy fortune of having some of those engineers work for me, nearly destroying hardware products we built for major television networks which could not properly extract said signals. Every engineer is taught about “PLL” design in school but the reality is very different in real world than in a textbook.

While we have focused on interface jitter in this topic, that is not the only area of problems. DAC performance can be impacted in a number of other ways, given the delicate signals it is trying to reproduce. Take the voltage of an AA battery and divide by 65536 for a 16 bit system, which is ~35 millionth of a volt. Heaven help you if you try to reproduce 24 bits because then you divide by 16 million!

Digital audio reproduction is therefore highly complex and difficult. With mass market consumers being so price conscious, a typical engineer working for on a mass market design, is not going to try to be heroic. He has to hit severe price points so he is going to go for what you can see: the list of logos on the box, wattage numbers and such. That is the priority. Not getting that last bit of 16 bit audio sample accurately. He is doing his job, making sure he can put food on the table and keep his company in business.

Enter high-end companies. With cost shackles removed, they can go as far as they dare to go. Now, just as you can’t become a better artist with a more expensive brush, there is no guarantee that because you don’t have cost constraints, you are producing great products. I recently reviewed a $16,000 DAC+amp combo and found its sound anything but refined. But companies like Harman (Mark Levinson, Revel, JBL, Crown, Lexicon) that base their design not just on some gray hair engineer’s idea of good sound, but couple it with careful listening tests and measurements do put the dollars to good use.

This nicely segues into the next topic: blind listening tests to prove audibility of such artifacts. Unfortunately, timing problems in digital interfaces do not lend themselves well to controlled experiments. For one thing, there is infinite variety in jitter. It can be random, periodical, data dependent, or discontinuous. And all combined in different levels. Where do you start? Well, folks started with random – the worst kind to go after. Why? Because random jitter just adds noise to the system and in that sense, it is least audible. See my debate with Ethan on more. I post the spectrum of the dcs DAC where you see it had jitter at 2KHz. That was not random at all.

Worse yet in my opinion is selection of material. I don’t know why people think “audiophile” music is the right content. We are not trying to enjoy music in these tests. We are trying to instrument a system with our ears. This brings me to the answer to the study that found 90% of the people could not tell the difference between CD and 64 Kbps version. At this rate, 95% of the original file was thrown way yet folks thought nothing had happened to it. Music codecs are good but not that good! Answer was the selection of music. The test agency thought that they should pick what audiophiles might listen to and naturally went for classical music and such. Well, classical music is harmonic and perceptual compression systems do wonderfully there. Where they get in trouble is when you have sharp transitions such as guitar strings, voices, etc. Even there, you need some quiet around it so that you can hear the so called quantization noise. Any one of my own stash of “codec buster” tracks would have blown the door open letting people hear the difference far, far easier. But that was not picked and from then on, the test was doomed despite perfect methodology otherwise.

So it is not enough to say this test was blind this, and ABX that, and run off with their conclusions. You need to first prove, as I just did with the science of compression that such content was going to be revealing of the problem we are chasing. MPEG put together its suite of audio tests we use to evaluate audio compression. None are audiophile music by any stretch. But they are very revealing as they must be. Where is the similar set of test files for jitter? Or frankly, for all the ills of digital audio? They don’t exist. People use random selection of music and then wonder why their outcome is close to random. Well duh!

I have been thrown at these tests before. Lack of good content makes the job very hard. You are under the stress of answering an AB question and you shouldn’t have to squint to read the tiny differences. Magnify them for me. Don’t tie my hand behind my back and expect me to perform miracle. My ear is not an instrument and there is a limit to my patience. Don’t push me to vote randomly and dilute the overall results that way. If you give the right track and I still couldn’t tell, then I will live with the results.

Given the paucity of data in this space then, what should we do? One answer is to put one’s head in the sand and say it is all good. Well, don’t you want to be sure? Isn’t that why you spend so much time here? One way to get there, at least partially, is to look at measurements. Within bounds, they are pretty reliable metrics of the quality that went into a design. I like to shoot for 16 bits of performance. If the system does that truthfully, I feel good. 20 and 24? The former is heroic, the latter impossible.

To be sure, Arny’s flag is super tempting to follow. Wouldn’t it be good if all equipment is cheap and I can just go by linear specs like power and number of logos as I mentioned? Sure. I won’t deny that as I used to do the same, making fun of all my audiophile friends. But then I took the first step going beyond textbook theory and into the real world of building such products and testing people left and right on all of this. Learned the value of auditory training in this space and seeing that occasional person walk off the street and beating me at that game! To be sure, most audiophiles are quite bad in hearing such artifacts but not all.

Hopefully I have demonstrated in this thread how deep this rabbit hole really is. And that the opposing view is a tough place to stand in the absolute. The math, the numbers, and the graphs are ruthless and powerful in the way they convey their message.

You do not have to take my position by the way. All I want you to do is be more informed. Understand the complexity of topic and don’t let one liners thrown out by the “it all sounds the same” as what guides you. Use this thread as a primer to learn more. Digital audio is not intuitive to any of us as this thread hopefully shows. You want to follow science, do it right.

On a personal note, I have grown to like Arny in this thread. Don’t ask why but I find him likable. Maybe because he is an old analog hack like I am. Or maybe because he makes it possible for me to answer his challenges with smile and excitement. Wish I didn’t have to take him on as I did. Alas, you can’t lead an army for a cause if you don’t understand the cause itself. And the cause is complex here. It doesn’t lend itself to one-liners that he came into this thread with and damning the future of where we need to go which is the target device being in charge of reproduction over a data bus like USB/network.

Can I blame him for not knowing all that is needed to know? No. As shown, the topic requires wide-ranging knowledge across an incredible array of topics from math to audio and computers. I have been fortunate that my employers have paid me to learn this stuff over the last 30 years, augmented by interacting with fine folks in this forum and elsewhere.

Don’t take the above as I know it all. I don’t. There are layers of complexity here and you can only hope to peel back some of them.

So how was this for a Sunday sermon? :D
 
Bravo Amir!

That is an excellent post Amir; written with zest, wit and wisdom! :)

You have spoken intelligent words within the paragraphs of your ideas and beliefs, based on your experience.
I give you a 10/10 for your effort on this Sunday afternoon! :D

Me I believe that by eliminating 'jitter' you are getting closer to the best truth!

And a 20-bit of dynamic range is all you truly need. Heck, 18-bit is fine.
And a sampling audio frequency of 88.2 Khz is also all the sufficiant maximum needed!
{A double of 44.1 Khz is simply simple and perfect enough! But any other multiple of it; 176.4 Khz, 352.8 Khz, 705.6 Khz, 1,411.2 Khz & 2,822.4 Khz can't hurt!}

Pure DSD from SACDs?
 

Orb

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I really do not know how you manage to keep your head there, same with JA when he gets the inquisition.
Shame he started to criticise Paul Miller in that thread as well, quite astounding tbh, especially as Paul Miller is a successfully recognised testing-measurement developer with skills-knowledge way beyond his in that scenario.
Still gives me plenty to read there in my bored moments lol.
BTW bad news, showing of the Pioneer with good jitter no longer applies to Pioneer, well their latest AVR with 1.4 HDMI has gone waaaay backwards, to the extent Paul Miller did an article about it called 1 step forwards and 2 back lol.
Suffers really bad jitter now in latest model, even with the special function enabled unless this somehow has been rectified by firmware recently (which I doubt).

Thanks again Amir.
Aub
 
May 30, 2010
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Amir,
Very interesting Sunday sermon - I really enjoyed your summary about digital audio.

I would like to put some one more log in your fire. People sometimes forget all DACs have an analogue stage after the DAC and that the performance of this part of the circuit strongly affects the whole listening evaluation of the system. Some people even say that it is the most critical part of the device.
 

fas42

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People sometimes forget all DACs have an analogue stage after the DAC and that the performance of this part of the circuit strongly affects the whole listening evaluation of the system. Some people even say that it is the most critical part of the device.
Of course. As I said in a another post, digital is digital and analogue is analogue. Once you're in analogue territory all bets are off; the really hairy area is within the very precise area where the real transition occurs between one state and the other, and the key engineering task is to have clean signals here. There are straightforward engineering solutions to this, and if they are not used, or badly implemented then of course you will get yourself into trouble. Playing games with components further back in the chain is a relatively ineffective, inefficient and typically expensive means of trying to improve things ...

Frank
 
Jul 1, 2010
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I used to doubt the audibility of jitter in competent digital devices, but Amir and Vincent have convinced me that it is real. Of course they have convinced me that it is audible when it's unusually high, and you're listening to music that reveals it easily, and you know precisely what to listen for, and you're listening at somewhat abnormally elevated levels. So now I've concluded that it is sort of the harmonic distortion of the digital age. Something that is very real, very measurable, but not really much of an issue unless it is allowed to get way out of hand. But that hasn't kept manufacturers from driving it further and further below the threshold of audibility and using that as a marketing differentiator.

But I could be wrong about that too. Audible jitter in digital audio could be as common as surface noise on vinyl, and I just don't know it when I hear it. As I've just admitted, I've been wrong before.

Tim
 

fas42

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So now I've concluded that it is sort of the harmonic distortion of the digital age. Something that is very real, very measurable, but not really much of an issue unless it is allowed to get way out of hand. But that hasn't kept manufacturers from driving it further and further below the threshold of audibility and using that as a marketing differentiator
Agree 100%.

Frank
 

Orb

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Heh just listening to the SP debate between JA and Arny.
Funny but 20mins to 25mis Arny admits that doing several passes of 5 amps it is possible to hear audible differences, while also debating that ideal (and these were ideal) products including amps sound the same.
27mins in he then says they are transparent.

Anyway interesting debate and worth listening to if have the time, thanks to SP for keeping it published and for JA for doing such events (appreciate his scientific knowledge-experience)
http://www.stereophile.com/news/050905debate/
The mp3 is just above the picture.
In the last 5 seconds you can hear it starting to kick off while JA is doing the closure speech, making me smile but it is really unfortunate and says it all - some things never change in such subjects:)

Cheers

Orb

Edit:
Reading that thread on the other site, I wonder if Arny is aware that even within same manufacturer that different models (and possibly firmware) gives different jitter results over HDMI, anyway his example is using the reference Yamaha AVR Z7 (at time) over here in UK.
Just saying this as on the 1st page this is not the same as the model Arny is using from the PMiller website, also I do know that PM measurements have fluctuated greatly between model revisions updated (not necessarily for the better) or between middle and higher end models in same manufacturer.
Amir, I feel your context of use is good though:)

Thanks
Orb
 
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sasully

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So it is not enough to say this test was blind this, and ABX that, and run off with their conclusions. You need to first prove, as I just did with the science of compression that such content was going to be revealing of the problem we are chasing. MPEG put together its suite of audio tests we use to evaluate audio compression. None are audiophile music by any stretch. But they are very revealing as they must be. Where is the similar set of test files for jitter? Or frankly, for all the ills of digital audio? They don’t exist. People use random selection of music and then wonder why their outcome is close to random. Well duh!
Under 'research' conditions, OF COURSE one should maximize the potential for subjects to detect difference -- this means training, and 'revealing' test material.

BUT: let's talk about the rough and tumble of , say, audio boards on the Web, shall we?

There, audiophiles are constantly claiming they hear difference between A and B, using 'sighted' test conditions X. Often it's big, obvious difference. Sometimes it's 'subtle' but 'real'. Sometimes it takes hours, days, weeks, to manifest itself.

All that's formally required to test the 'reality' of that difference, is to test it under DBT conditions. Same audio samples, same gear, same listener.

If they 'fail', it would not mean that no one else could hear a difference between A and B under condition X -- much less condition Y. It would mean that THEIR original claim is not supported.

Btw this is great for audiophiles...it always gives them an 'out', which they always take anyway -- 'Well, maybe it's not real on YOUR system, with YOUR recordings, but it is on MINE!" (see: responses to Meyer and Moran's DBT of SACD vs CD)


I have been thrown at these tests before. Lack of good content makes the job very hard. You are under the stress of answering an AB question and you shouldn’t have to squint to read the tiny differences. Magnify them for me. Don’t tie my hand behind my back and expect me to perform miracle. My ear is not an instrument and there is a limit to my patience. Don’t push me to vote randomly and dilute the overall results that way. If you give the right track and I still couldn’t tell, then I will live with the results.
So, what to make when people claim they hear jitter (or more properly, believe they hear a difference, and ascribe it to jitter because of something they read -- maybe even read here?) Do you have a sermon for them?


Given the paucity of data in this space then, what should we do? One answer is to put one’s head in the sand and say it is all good. Well, don’t you want to be sure? Isn’t that why you spend so much time here? One way to get there, at least partially, is to look at measurements. Within bounds, they are pretty reliable metrics of the quality that went into a design. I like to shoot for 16 bits of performance. If the system does that truthfully, I feel good. 20 and 24? The former is heroic, the latter impossible.

Can you demonstrably hear 16 vs 15 bits performance in your room, with loudspeakers playing music? Or does it require good headphones and carefully selected recordings?


To be sure, Arny’s flag is super tempting to follow. Wouldn’t it be good if all equipment is cheap and I can just go by linear specs like power and number of logos as I mentioned? Sure. I won’t deny that as I used to do the same, making fun of all my audiophile friends. But then I took the first step going beyond textbook theory and into the real world of building such products and testing people left and right on all of this. Learned the value of auditory training in this space and seeing that occasional person walk off the street and beating me at that game! To be sure, most audiophiles are quite bad in hearing such artifacts but not all.
But anyone can call themselves an audiophile, after all.


Hopefully I have demonstrated in this thread how deep this rabbit hole really is. And that the opposing view is a tough place to stand in the absolute. The math, the numbers, and the graphs are ruthless and powerful in the way they convey their message.
The message they convey, so far is: jitter numbers that look scary high, might or might not have much audible effect.

You do not have to take my position by the way. All I want you to do is be more informed. Understand the complexity of topic and don’t let one liners thrown out by the “it all sounds the same” as what guides you.

There is no one faction of the hobby that says 'it all sounds the same'. But I notice a lot of lazy, or disingenuous, writers on audio online, like to pretend such a straw man exists.

What there is, is a faction that says: dearest audiophiles, before you start clutching your pearls over jitter, (or cables, or transports, or power amps, or 16 vs 24 bits, or CD vs 'high rez') -- worry about your room acoustics; worry about your loudspeakers; worry about your own hearing; worry about how well recordings are made; worry about having enough power to drive your speakers in your room at the levels you like to listen, without distortion. These are far, far, far, far, more likely to be degrading your listening experience.
 
Apr 3, 2010
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There, audiophiles are constantly claiming they hear difference between A and B, using 'sighted' test conditions X. Often it's big, obvious difference. Sometimes it's 'subtle' but 'real'. Sometimes it takes hours, days, weeks, to manifest itself.

All that's formally required to test the 'reality' of that difference, is to test it under DBT conditions. Same audio samples, same gear, same listener.
The challenge is how easy it is to conduct such a test and what motivation the tester has to do it. On the latter, the only motivation would be to win an argument on a forum. That is not a lot of motivation.

On the work side, I suspect you will ask for ABX test. That requires computer controlled switching and tracking of the results. No one has such a thing sitting around their home. Even if they had the apparatus, creating the actual test fixture may be non-trivial. Take speaker cables. I need to have two relay boxes at both ends to switch over cables. Even if we built such a thing, we now have a new problem. What they heard sighted, didn't have the relay box. But here we have added it. Now, the objectivist side argues it shouldn't make a difference. But then again, if we were to accept their opinion, the test would not be necessary to start!

That said, yes, when the test is easy, people should run it. I just documented my last semi-objective tests of media players. It took a couple of hours to do it but I managed to get there and realized bias was at play.

Btw this is great for audiophiles...it always gives them an 'out', which they always take anyway -- 'Well, maybe it's not real on YOUR system, with YOUR recordings, but it is on MINE!" (see: responses to Meyer and Moran's DBT of SACD vs CD)
They do which makes me wonder why the other side keeps challenging them on it ;) :). It is not like many go and run these tests if they are non-trivial to do!

Here is the more ironic side. I can't get any objectivist to go run these tests either! I have argued 'till I am blue but they won't conduct the simplest tests. They will complain the results will be "useless" because it would not be statistically valid, won't be blind enough, is too hard, the results too obvious, etc. ,etc. I just argued this point this very morning on another forum with a guy who has been chasing me forever. The other next to him who has been lecturing the same, confessed that he doesn't blind test his own speakers because it is not "necessary!"

This all points to us being human. We don't want to do a bunch of work for the sake of winning an argument. Or the fear that the results might surprise us. A few of us are crazy enough to do tests but is not enough to get people to follow us.

So, what to make when people claim they hear jitter (or more properly, believe they hear a difference, and ascribe it to jitter because of something they read -- maybe even read here?) Do you have a sermon for them?
I don't follow. Do you mean I should just argue with them for the sake of it???

Can you demonstrably hear 16 vs 15 bits performance in your room, with loudspeakers playing music? Or does it require good headphones and carefully selected recordings?
Like all digital artifacts, sometimes you can hear these things, other times you cannot. Well designed systems though don't have artifacts that come and go. We can compromise to be sure but we need to understand that we have.

To answer your specific question, no, I have not attempted to create such a test.

But anyone can call themselves an audiophile, after all.
And just as many people call themselves "objectivists, keeper of the truth, etc," There are no angels here.

The message they convey, so far is: jitter numbers that look scary high, might or might not have much audible effect.
Correct. But there is another point. Once you get below 500ps for 16-bit, 44.1Khz audio, it is inaudible. Since achieving that point is not hard these days, there is no reason to debate the gray area above. For a few hundred dollars, you can take a PC and turn it into a music server with superlative jitter specs and be good to go.

There is no one faction of the hobby that says 'it all sounds the same'. But I notice a lot of lazy, or disingenuous, writers on audio online, like to pretend such a straw man exists. What there is, is a faction that says: dearest audiophiles, before you start clutching your pearls over jitter, (or cables, or transports, or power amps, or 16 vs 24 bits, or CD vs 'high rez') -- worry about your room acoustics; worry about your loudspeakers; worry about your own hearing; worry about how well recordings are made; worry about having enough power to drive your speakers in your room at the levels you like to listen, without distortion. These are far, far, far, far, more likely to be degrading your listening experience.
Two points:

1. I don't accept your assertion. I argue with them all the time. You hear lines all the time that if so and so equipment is "properly" designed, it would all sound the same. Ask them if there is a difference between CD players. That is the answer you get. Ask them about amps. That is the answer you get. Ask them about cables. That is the answer you get. The only area they don't give that answer is speakers. But by all means, tell me your views on all the examples I just gave.

2. You are right, they are so fixated on the other side. Why? It makes no sense to me. Speak about your own position. Why be so obsessed with the other side? Last night I got the nastiest, nastiest PM on another forum for daring to challenge the objectivists on differences between amps. The only thing that poster didn't wish for me is to die the next day. And this is from a very senior and respected member of the other forum. Why would he worry so much about my views to wish me so many bad things? Why not discuss the technology and not the person and his values?

BTW, welcome to the forum :).
 

sasully

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Heh just listening to the SP debate between JA and Arny.
Funny but 20mins to 25mis Arny admits that doing several passes of 5 amps it is possible to hear audible differences, while also debating that ideal (and these were ideal) products including amps sound the same.
27mins in he then says they are transparent.

What he's responding to is John Atkinson claiming that its extraordinarily hard for blind tests 'to produce anything but a null result even when real audible difference exist' and it is a test that 'does not work'. Which is simply wrong. (He also talks of conclusions that are 'right for [listeners in this room]', an interesting scientific concept). Arny notes this by pointing to non-null ABX results that Tom (Nousaine) has heard. You can also find some on the ABX website .e.g.,

here
http://home.provide.net/~djcarlst/abx_data.htm
here
http://home.provide.net/~djcarlst/abx_cd.htm
here
http://home.provide.net/~djcarlst/abx_f4.htm

and more. These were some of the earliest ABX tests done...and they produced positive results in some cases, negative in others. Were the positive ones 'hard' to produce'?

Then Atkinson says he's talking about Tom Nousaine's several null-results DBTs of high-end vs mass market amps (tests which are famous irritants to 'audiophiles'). (He also misrepresents Nousaine's position -- Nousaine doesn't conclude 'no differences exist' between ALL amps, based on his tests. Tom knows how to qualify his claims to fit the data.) To him they proves that DBT masks real difference. Why? Because he *knows* they sound different. He just knows. Arny rightly notes that Atkinson starts from a position that 'sighted' subjective experience trumps controlled subjective experience.

As for 5 passes, Arny it talking about taking a signal, sending it through an amp, then routing output back through the amp. Repeating that 5 times. Do the same thing with another amp. THEN differences between amps become audible by ABX -- which suggests that the differences are real but marginal, that is, not going to manifest in normal use. Similarly, you can uncover real -- and unsurprising -- audible difference between amps by running one of them beyond its rated capacity (e.g. running a Krell and a mass-market Fischer near the top of the Krell's load-handling capacity). But you wouldn't do that, would you?

The basic issue here is whether it's 'hard to produce' a non-null amp ABX because ABX is flawed (as Atkinson claims), or simply because...those differences are truly rare under normal conditions!
 

sasully

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Here is the more ironic side. I can't get any objectivist to go run these tests either! I have argued 'till I am blue but they won't conduct the simplest tests. They will complain the results will be "useless" because it would not be statistically valid, won't be blind enough, is too hard, the results too obvious, etc. ,etc. I just argued this point this very morning on another forum with a guy who has been chasing me forever. The other next to him who has been lecturing the same, confessed that he doesn't blind test his own speakers because it is not "necessary!"
That's not ironic, Amirm. Audible loudspeaker difference can rationally be assumed to exist, from what we DO know about human hearing and the way loudspeakers work. The source of *preference*, of course, may include bias factors. So that guy would be foolish to claim he was ONLY basing his preference on sound. But to claim his speakers sound different from others, is not foolish , even if not rigorously proved.

Without some solid support data already existing, the onus is on people saying the audio phenomenon is real, to demonstrate that it is. Lacking that, the prudent course is to always admit that something 'heard' could be imaginary. I simply don't see 'audiophiles' doing that on anything like a routine basis.

And THAT btw, is the crux of the 'contention' across all audio, isn't it. It's people making claims beyond what the data merits.

Btw, I've done plenty of DBTs myself, to compare audio files, using foobar2000's comparator. I'd be happy to take a DBT that you or someone else competent set up, to demonstrate jitter audibility under condition X.




I don't follow. Do you mean I should just argue with them for the sake of it???

If you're trying to suggest you don't enjoy arguing fro the sake of it, sorry, I'm not buying it. :D


And just as many people call themselves "objectivists, keeper of the truth, etc," There are no angels here.

But your self-appointed role seems to be devil's advocate. So don't complain if you get pushback.


Correct. But there is another point. Once you get below 500ps for 16-bit, 44.1Khz audio, it is inaudible. Since achieving that point is not hard these days, there is no reason to debate the gray area above. For a few hundred dollars, you can take a PC and turn it into a music server with superlative jitter specs and be good to go.
It's in fact what I do -- but not because I was worried at all about jitter.



1. I don't accept your assertion. I argue with them all the time. You hear lines all the time that if so and so equipment is "properly" designed, it would all sound the same.
And that is a VERY DIFFERENT proposition than just 'it all sounds the same'. That (and level matching) are actually crucially important qualifiers. To elide them is lazy at best, shady at worst.


Ask them if there is a difference between CD players. That is the answer you get. Ask them about amps. That is the answer you get. Ask them about cables. That is the answer you get. The only area they don't give that answer is speakers. But by all means, tell me your views on all the examples I just gave.
Actually 'they' don't give that answer about transducers generally (cartridges for example). Transducers can be expected to sound different for nonmagical reasons.

As for the rest: no, they shouldn't sound different, except for mundane, easily avoided, non-magical reasons (like, long runs of 21g speaker cable versus 12g, or running one poweramp into distortion and the other not, or one CDP has a significantly higher output voltage than the other and you didn't level match)


2. You are right, they are so fixated on the other side. Why? It makes no sense to me. Speak about your own position. Why be so obsessed with the other side? Last night I got the nastiest, nastiest PM on another forum for daring to challenge the objectivists on differences between amps. The only thing that poster didn't wish for me is to die the next day. And this is from a very senior and respected member of the other forum. Why would he worry so much about my views to wish me so many bad things? Why not discuss the technology and not the person and his values?

Oh, dear, let me get out my tiny violin and play along to this sad aria!

I've been 'in the online trenches' on the so-called 'Great Debate' on audio matters ('subjective' vs 'objective' ) for a couple of decades...long than you, I'd wager. Arny longer still! I've seen some incredibly nasty behavior from the 'subjectivist' side, but worse, I've seen no lessening of snake-oil and anti-science being touted by the 'high end' and its apologists. I've seen plenty of fury directed against people who dare to note the uncontroversial scientific fact that human perception of audio difference is fallible and subject to bias... and as a scientist that bugs me. So I have no respect for the 'oh gosh why are you so OBSESSED' diversionary tactic.

I'm talking about rational assigning of 'worry' in the face of a blizzard of misinformation that confronts the audio hobbyist, flowing mainly from the 'high end'. It's absurd to worry about jitter when your listening room has a bare wood floor with a glass top coffee table between you and the speakers. It's absurd to pine for 88.2kHz delivery formats when your hearing tops out at 16.


BTW, welcome to the forum :).
Been at WBF awhile, really. I was here as soon as the esteemed Dr. Olive opened his shop. :)
 

Steve Williams

Site Founder, Co-Owner, Administrator
Been at WBF awhile, really. I was here as soon as the esteemed Dr. Olive opened his shop.
stay tuned for Sean's next article which he is presently working on
 
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That's not ironic, Amirm. Audible loudspeaker difference can rationally be assumed to exist, from what we DO know about human hearing and the way loudspeakers work. The source of *preference*, of course, may include bias factors. So that guy would be foolish to claim he was ONLY basing his preference on sound. But to claim his speakers sound different from others, is not foolish , even if not rigorously proved.
I don't want to keep arguing about a person who is not here. But will say that he was saying his new speaker was better than the last design but that he did not need to show that using blind tests. I don't buy that.

Btw, I've done plenty of DBTs myself, to compare audio files, using foobar2000's comparator. I'd be happy to take a DBT that you or someone else competent set up, to demonstrate jitter audibility under condition X.
If you read this thread, you will see that such a test is not representative of much.. Jitter is a three-dimensional metric that incorrectly gets boiled down to one number for its amplitude. You must look at its spectrum and that spectrum determines how audible it is. This is why I say it is a messy gray area. It is like asking how imbalanced your tires need to be before you notice the vibrations. My answer is just get them balanced and don't worry about it! Get jitter to be low enough and be done with it. This is not a high-cost venture where we have to justify the expenditure. The solutions are pretty cheap these days.

Oh, dear, let me get out my tiny violin and play along to this sad aria!
:(. Here is the thing. You said you have seen these arguments for two decades. If we could get 10% of those people to understand the human side of this and not make it their mission to p*ss off the other side, the world would be a better place. Without it, the world goes on as it always has.

BTW, as to when I first read such arguments. It goes back to 1982-1983 :).

I'm talking about rational assigning of 'worry' in the face of a blizzard of misinformation that confronts the audio hobbyist, flowing mainly from the 'high end'. It's absurd to worry about jitter when your listening room has a bare wood floor with a glass top coffee table between you and the speakers. It's absurd to pine for 88.2kHz delivery formats when your hearing tops out at 16.
I hear this argument all the time. You say I shouldn't characterize the other side as all things sound the same but you go on and generalize that the typical audiophile spends money on jitter and not acoustics. That is not so. We have a ton of acoustic topics and experts in this forum.

Also, there is nothing in science that says that room effects mask digital distortion. The former is linear the latter is not. I could very well be annoyed by jitter in treated or untreated room.

As to higher frequency sampling, let's leave that for another thread.
 

Orb

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What he's responding to is John Atkinson claiming that its extraordinarily hard for blind tests 'to produce anything but a null result even when real audible difference exist' and it is a test that 'does not work'. Which is simply wrong. (He also talks of conclusions that are 'right for [listeners in this room]', an interesting scientific concept). Arny notes this by pointing to non-null ABX results that Tom (Nousaine) has heard. You can also find some on the ABX website .e.g.,

here
http://home.provide.net/~djcarlst/abx_data.htm
here
http://home.provide.net/~djcarlst/abx_cd.htm
here
http://home.provide.net/~djcarlst/abx_f4.htm

and more. These were some of the earliest ABX tests done...and they produced positive results in some cases, negative in others. Were the positive ones 'hard' to produce'?

Then Atkinson says he's talking about Tom Nousaine's several null-results DBTs of high-end vs mass market amps (tests which are famous irritants to 'audiophiles'). (He also misrepresents Nousaine's position -- Nousaine doesn't conclude 'no differences exist' between ALL amps, based on his tests. Tom knows how to qualify his claims to fit the data.) To him they proves that DBT masks real difference. Why? Because he *knows* they sound different. He just knows. Arny rightly notes that Atkinson starts from a position that 'sighted' subjective experience trumps controlled subjective experience.

As for 5 passes, Arny it talking about taking a signal, sending it through an amp, then routing output back through the amp. Repeating that 5 times. Do the same thing with another amp. THEN differences between amps become audible by ABX -- which suggests that the differences are real but marginal, that is, not going to manifest in normal use. Similarly, you can uncover real -- and unsurprising -- audible difference between amps by running one of them beyond its rated capacity (e.g. running a Krell and a mass-market Fischer near the top of the Krell's load-handling capacity). But you wouldn't do that, would you?

The basic issue here is whether it's 'hard to produce' a non-null amp ABX because ABX is flawed (as Atkinson claims), or simply because...those differences are truly rare under normal conditions!
I appreciate that sasully,
my point though that in a debate one should be consistent and unfortunately it felt to me JA was more so than Arny, with this being one clear example where to "win" the debate it seems the statement switched - possibly due to over emphasising the point by Arny.
In terms of how Arny used these in the debate I feel cannot be defended.
Others may have a different view, hence why I comment where to listen and for others to make up their own mind.
As an example I do not name who I feel is the voice that is kicking off at the end, just that someone is starting to talk very loudly/shout while JA closes up and thanks all for attending.

The problem is this, in a debate such as that or even on this topic online, if one cannot keep the emotion out of their thought process then biases set in, I have seen this with intelligent members even at HydrogenAudio where there are some incredibly talented posters and some where bias can skew their decisions.
This is one reason I admire JA because out of everyone I see posting, he is the most consistent (and also with his facts-experiences-testing), I get the feeling you may also be a HA member so as an example is the posting done in the recent 24bit discussion involving JA's presentation to members of the public.

Edit:
Also just want to say that JA also picks up and queries Arny on what your explaining Sasully in that recorded debate, however I think its best for people to listen to the debate between them two rather than you and me trying to explain it, especially as I raised this originally in context to that audio meeting.
That way everyone can make up their own mind with the recorded and presented facts.

Cheers
Orb
 
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sasully

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Jun 30, 2010
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I appreciate that sasully,
my point though that in a debate one should be consistent and unfortunately it felt to me JA was more so than Arny, with this being one clear example where to "win" the debate it seems the statement switched - possibly due to over emphasising the point by Arny.
In terms of how Arny used these in the debate I feel cannot be defended.
Others may have a different view, hence why I comment where to listen and for others to make up their own mind.
As an example I do not name who I feel is the voice that is kicking off at the end, just that someone is starting to talk very loudly/shout while JA closes up and thanks all for attending.

Earlier you wrote:
In the last 5 seconds you can hear it starting to kick off while JA is doing the closure speech, making me smile but it is really unfortunate and says it all - some things never change in such subjects
I didn't understand then and I still don't -- and I was physically *at* that debate, in the audience. Immediately after the debate I went and said hi to Arny at the dais, then went off to speak with Tom Nousaine elsewhere in the room. I'm told there was a verbal fracas of some sort between Arny and Mikey Fremer, but I didn't witness it.

In the recording I can faintly hear someone saying something about '...blind test in the last 20 years' . Can you make out more?




This is one reason I admire JA because out of everyone I see posting, he is the most consistent (and also with his facts-experiences-testing), I get the feeling you may also be a HA member so as an example is the posting done in the recent 24bit discussion involving JA's presentation to members of the public.
Plummy British enunciation, courtly manners, and a knack for debate tactics, go a long way with some people. But alas it doesn't necessarily make him right, nor does it make the 'spin' he puts on things invisible. Btw, I'm 'krabapple' on HA, and a few other places; and I think you left something off your sentence there. If you are referring to JA's travelling roadshow 'demo' of lossy compression and various other formats, then yes, its flaws are dissected in all their gory detail on a thread or two at HA.

Also just want to say that JA also picks up and queries Arny on what your explaining Sasully in that recorded debate, however I think its best for people to listen to the debate between them two rather than you and me trying to explain it, especially as I raised this originally in context to that audio meeting.
That way everyone can make up their own mind with the recorded and presented facts.
Indeed, though nothing beats being there.
 
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Orb

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Sep 8, 2010
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Ah I thought I recognised the name, bah I must be suffering brain fudge not to be able to place it :)
I have heard more than that and how it ends with that last 5 seconds the start of what became the full on argument you touch on, BTW it comes across faintly because of the recording quality and mic position, however, it is easy to hear someone becoming quite emotional and starting to shout.
JA's approach is not about British enunciation, it is about a methodical emotionless approach done willfully-disciplined to remove emotional based biases, this comes across in the thread in HA where if reading it fully JA managed to move a hostile thread with biases showing to one with actually really good information/food for thought from other HA posters.
While not a member at AVSForum, I have posted at Stereophile bias and debiasing papers as the subject really interests me; which shows just how biased we are, sorry to say that also includes at times you/Arny/JJ (who I respect but loses his cool with some audiophiles lol)/Amir/me/etc.
The one who does not "lose it" these days and going back a few years and is consistent is JA, and it is comes back to a methodology of dealing with biases, which unfortunately the rest of us are pretty poor at doing and I feel does skew are thoughts and posting on this subject.
I did link that HA topic in another digital thread here as it was pretty interesting-important with information presented.

That said, Amir should we take all our recent posts and move them to a new thread?
I do not mind either way but we are going offtopic, and I appreciate this is caused by me as sasully was responding initially to my post, which you also seems to like to discuss.
Thanks
Orb
 
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Orb

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Hey not me bud :)
If Amir and Sasully really want to go further with this then maybe Amir can move the last posts in this thread or copy them to a new one.
I am happy that the recorded debate has the facts laid out for listeners and provides a for/against - I do hope others bothered to listen to it as it touches on some never ending audiophile topics :)
And yes I appreciate this makes me lazy - bad me :)

Cheers
Orb