The 2011 Richard C. Heyser Memorial Lecture: "Where Did the Negative Frequencies Go?" Nothing is Real

Nothing Is Real
It is a common put-down of audiophiles: "You're imagining things." But is this a meaningful criticism? Is there a real difference between "reality" and "illusion"? Or was Professor Dumbledore on to something?

I have been interested in human perception almost as long as I have been working in magazines. This sound is something with which everyone in this room will be familiar: a 1kHz tone at –20dBFS.

[Play 1kHz, –20dBFS sinewave tone]

What I'd like you to do now is to imagine the same tone for 10 seconds.

I believe a scan of your brain would show the same activity in both situations: with a "real" sound and with an "imaginary" sound. We can't directly experience reality; instead, our brain uses the input of our senses to construct an internal model that reflects that external reality, to a greater or lesser degree. So what is reality, what is the illusion? Internally, they are the same thing. That's why hallucinations are so unsettling—there is no way of knowing without further investigation that they don't correspond to anything in the outside world.

I am sure that some are shifting a little in their chairs, so I will demonstrate this conjecture with some music. A couple of years after the Abbey Road sessions I mentioned earlier, the band got back together to record an album for DJM Records. Here's a picture of us in 1974: three sharp-dressed men.


The Obie Clayton Band (L–R): John Atkinson, Michael Cox, Alan Eden

Baggies and platform shoes were mandatory in 1974, otherwise Mark Knopfler wouldn't have had anything to rail against in Dire Straits' "Sultans of Swing." Here's a needle-drop of a track from our LP, which was released in 1975, engineered by Jerry Boys (of subsequent Buena Vista Social Club fame), produced by Tony Cox at Sawmills Studio, and mastered by George Peckham. (Yes, it was a "Porky Prime Cut.") I am playing bass guitar, I'm one of the backing vocalists, and I supply the choir of clarinets in the bridge.

[Play Obie Clayton Band: "Blues for Beginners," needle drop from Obie Clayton LP, DJM DJLPS 458 (1975)]

Think about what you've just heard. I mentioned bass guitar, vocals, and clarinets. There is also a lead singer, a piano, guitars, drums, a harmonica. What's so unusual about that?

What is unusual is that none of this is real. There are no individual sounds of instruments being reproduced by the loudspeakers. Even though you readily hear them, there is no bass guitar, there are no drums, there is no lead vocalist. The external reality is that there are two channels of complex audio-bandwidth voltage information that cause two pressure waves to emanate from the loudspeakers. Everything you hear is an internal construct based on your culture and experience. The impression you get at 2:51 that someone is striking a match to light a cigarette at the right of the stage is something that exists only in your head, your brain back-interpolating from the twin pressure waves striking your ears that that must have been what happened at the original event.

I first heard this phenomenon described in a talk given by Meridian's Bob Stuart a quarter century ago, and it was discussed at length in Edmund Blair Bolles's A Second Way of Knowing: The Riddle of Human Perception (Prentice Hall Press, 1991). Your brain creates "acoustic models" as a result of the acoustic information reaching your ears. We do this so naturally—after all, it's what we do when our ears pick up real sounds—that it doesn't strike us as incongruous that the illusion of the sounds and spatial aspects of a symphony orchestra can be reproduced by a pair of speakers in a living room.

As with our experience of liquid water, the familiarity and apparent simplicity of perception hides depths of complexity. We just do it. Yet there is as of yet no measurement or set of measurements that can be performed on those twin channels of information to identify the sounds I have just described, and what you perceived with no apparent effort when you listened to that recording of my band.

So if the brain creates internal models to deal with what is happening in the "real" world, let's examine how those models work.


Live from the 131st AES Convention: JA throws a baseball for Stephen Mejias to catch.

I was at a Mets game a few years ago, thinking how difficult it is for an outfielder to catch a pop-up, given that when the ball leaves the bat, the fielder has almost no data with which to calculate where the ball will land. I was reminded of something Barry Blesser wrote in the October 2001 issue of The Journal of the AES (p.886). "The auditory system . . ." Blesser wrote, "attempts to build an internal model of the external world with partial input. The perceptual system is designed to work with grossly insufficient data."

Catching a ball illustrates Blesser's point, not just about the auditory system's but also the visual system's ability to use incomplete information. At first the fielder has very little info on which to create a model of the ball's trajectory. Certainly there is not enough information to program a robot to catch the ball (footnote 1). The robot needs to use math. By contrast, the fielder's brain continually updates the model with new information—a process of successive approximation, if you will—until, plop, the ball lands in his glove.

This internal modeling of reality is quirky. First, with visual stimuli, there is a latency of around 100 milliseconds while the brain processes new data. Visually, we experience the world as it existed a tenth of a second in the past. It has been proposed that we have evolved mechanisms to cope with that neural lag; in effect, our internal models predict what will occur one-tenth of a second in the future, which allows us to react to events in the present—such as catching a fly ball, or maneuvering smoothly through a crowd (footnote 2).

But certain situations can unmask that lag. Something that we must all have experienced is when we have glanced at a clock with a second hand or with a numeric seconds display: The first tick appears to take longer than subsequent ticks. But this isn't an illusion: the first tick does take longer—at least in your reality, as opposed to the clock's—because of the time required for the brain to accommodate new data into its model.

I remember discussing perception with Bob Berkovitz when I visited him at Acoustic Research in Boston, in the early 1980s. The conversation stuck in my mind because Bob, who was working with Ron Genereux on digital signal processing to correct room acoustic problems, defined audio as being "one of the few areas in which an engineer can work without the end product being used to kill people."

During that visit, Bob subjected me to a perceptual test. I sat in a darkened room with a red light flashing in the left of my visual field. At some point, Bob switched off the light on the left and turned on a similarly flashing red light on the right. The question is: What did I see?

The answer is not "A red light flashing on the left, then a red light flashing on the right."

What I saw was a flashing red light on the left that then slowly moved across my field of vision until it was on the right!

It was another moment of satori. The conflict between "reality" and what I perceived seemed to demonstrate that, once the brain has constructed an internal model, it is slow to change that model when new sensory data are received. The brain's latency in processing aural data is shorter than it is with visual data, but it still exists. Otherwise there wouldn't be the phenomenon of "backward masking," where a loud sound literally prevents you from hearing a quiet sound that preceded it.

Here's an audio example analogous to the clock's slower first tick with which everyone will be familiar. When you hook up a new component but with the channels reversed, at first, all you're aware of is that something is not quite right. The orchestral violins are on the left, as they should be, but their image wobbles, and is ambiguously positioned. You don't hear them on the right, where they now should be. Then, when you realize that Left=Right and vice versa, the imaging solidifies and is correctly heard as a channel-reversed image. The thought crystallizes the perception, not the other way around.

Although evolution has optimized the human brain to be an extremely efficient pattern-recognition engine that uses incomplete data to make internal acoustic models of the world, as this example suggests, that same evolutionary development has major implications when it comes to the thorny subject of sound quality.



Footnote 1: Following the lecture, I read in Steven Levy's 1984 book Hackers: Heroes of the Computer Revolution that students at MIT in the 1950s programmed a robot arm to catch a ball, but I don't have any further information on this. Also, on how a fielder manages to catch a ball, I am told that as part of the successive approximation process I describe, he adjusts his position to keep a constant angle between the ball and his eye.

Footnote 2: See, for example, the essay at www.luminous-landscape.com/tutorials/what_we_see.shtml.

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Comments
bernardperu's picture
Why would you read Stereophile anyway?

JhonnyR

 

If Stereophile has the principle of not doing DBT and for you doing so is a matter of principle why oh earth would you even care to read Stereophile? Your statement above suggests you have very extensive knowledge of the content of Stereophile's articles. So you keep reading stereophile's reviews knowing they are irremediably flawed?? How perverse is this?

 

The real question lies on your double blind tested hatred. 

 

Whatever your answer is I will have to assume that your hatred is a broken record and it will just go on.

GeorgeHolland's picture
He probably reads them as I

He probably reads them as I do for the laughs.smiley

JohnnyR's picture
You Didn't Comment..........

......on your error filled post above so why should I comment on your assumptions? If you wish to worship Fearless Leader then by all means bow down and do so. I myself prefer to ask questions and be skeptical about his "methods" and the reason "why" he doesn't test ALL items under review.

John Atkinson's picture
You're Welcome

Andreasmaaan wrote:
It's a pity that some proponents of DBT as the only valid methodology have used the comments thread here to launch personal attacks against JA.

Indeed. I am not sure why I have become a lightning rod for these audio skeptics. Perhaps it is because it is a matter of religious belief on their part - having had extensive experience of blind testing, I rejected it and thus became a heretic in their eyes. Or perhaps it is just our courtesy in allowing them the space on this website to express themselves.

Andreasmaaan wrote:
JA does measure every piece of gear his reviewers review - a practice which ensures that the opinions of the reviewers are grounded in objective data, or otherwise as the case may be.

As my reviewers do not see the measurements until after they have written the review, I take my hat off to them.

Andreasmaaan wrote:
To cut what is risking becoming a lengthy expression of indignation short: thank-you JA for a wise and thought-provoking read.

You're welcome and my thanks to everyone else who appreciated the preprint. It was an honor to have been invited by the Audio Engineering Society to give this lecture - it's not often that you get the opportunity to look back over a 4-decade career!

A Happy New Year to everyone who surfs this site.

John Atkinson

Editor, Stereophile

JohnnyR's picture
Ahhhhhhhhhh Typical Atkinson Answers

You ignore the errors and just plow along blissfully gobbling up the unwarranted praise.

"JA does measure every piece of gear his reviewers review"

As I pointed out above, along with other errors on the part of Andreasmaaan,you do NOT test every piece of gear your reviewers review, but then you pretended that you do in your response. Only certain items are tested by you. Please get your own facts straight if that's even possible for you to do so.

Regadude's picture
Johnny brand speakers

Johnny, I wish you a great new year 2013, in which you sell 10 times more of your home made speakers than in 2012. 

Since you sold zero of your speakers in 2012, you need to sell 10 X 0=0 speakers in 2013 to meet this objective. Maybe you can hire George Holland as your director of marketing and sales... 

Get cracking, you have only got 364 days left to sell your quota...

JohnnyR's picture
Happy 2013 Raghead

[flames deleted by John Atkinson]

Unlike yourself Raghead, I will be DESIGNING and BUILDING my own speakers and learning. You do know that word "learning"? Hmmmm maybe you stopped after age 10. You on the other hand will be on here *yawning* and acting the fool and spending your money on Stereophile reviewed crapola.yes

Regadude's picture
So only your speakers are good?

So according to you Johnny, everything Stereophile reviews is crapola?! There is not one good piece of equipment that has been reviewed by Stereophile? Hundreds of reviews, not one good product?

But you, in your basement, build quality speakers... 

I have challenged you before (as well as George) to name your gear. What kind of gear merits the Johnny seal of approval? 

As always, you always ignore my challenge (George chickened out to). It seems you can only complain, but cannot even provide a list of your gear. 

I guess ever seeing pictures of your "famous" speakers is also out of the question. 

All talk and no action. 

Regadude's picture
Johnny the pussy

So Johnny, where are your speakers pics and specs?

In your imagination.... [flame deleted by JA]

GeorgeHolland's picture
Johnny never offered to show

Johnny never offered to show you anything other than his backside which I think is approriate considering the childish actions of yourself.What does it matter what our audio components are? Anything we mention would be ridiculed by yourself no doubt. Sorry but I'm not playing your silly game. Good God grow up and act like a man for once will you? angry

John Atkinson's picture
Getting Facts Straight

JohnnyR wrote:
As I pointed out above . . . you do NOT test every piece of gear your reviewers review, but then you pretended that you do in your response. Only certain items are tested by you. Please get your own facts straight if that's even possible for you to do so.

Out of morbid curiosity, I looked at the past 15 issues of Stereophile - we published 98 full reviews and follow-up reviews. Of those 98 reviews, 83 were accompanied with a full set of measurements, or 84.5%. So even if not every review includes measurements, the vast majority do, which supports Andreasmaaan's point.

I have explained to you before, in other comment threads, why we do not publish measurements of analog playback components, which is due to lack of resources. I have also explained to you why we do not publish measurements of tweaks, which is that it it is difficult to determine exactly what to measure. I don't see any reason to reopen those discussions, but that you continue to be fixated on these two issues and continue to raise them is sad.

And, as I have warned you, JohnnyR, I am continuing to delete comments from you, and others, that are nothing more than flames aimed at other readers.

John Atkinson

Editor, Stereophile

JohnnyR's picture
Get Out Your Dictionary

"Reviews" means just that, any item reviewed by your staff. If you think "tweaks" don't qualify then they should be labled as "Opinions" not a review.angle All of those full reviews you speak of were what speakers, amps, preamps, cd transposrts and the like?

Yeah I know why you don't test tweaks, that would involve you using those horrible SBT or DBT. That's a really nice system you have set up. "We don't believe in DBTs or do them or can't afford to do them"......"We don't know what to test on the tweaks"..........add the two up and you get "We don't have to show that tweaks actually do anything other than what our "reviewer" subjectivly alludes to in their sighted biased listening using their golden ears"......EXCUSES Mr Atkinson plain and simple. no

Once more I ask you to read and comment about this link:

http://forums.audioholics.com/forums/loudspeakers/83412-diy-loudspeakers...

You seem to think DIY can't do anything right in your previous post in answer to Raghead. Insulting intelligent people that actually build better speakers than the status quo can produce is beyond being pompus in your case.THAT is what's SAD.

Don't you have some real work to be doing instead of being on the forums? I thought that was Ariel's job. Let him earn his pay.

ChrisS's picture
Circle Game

JRusskie,

Look up "fixation" and "perseveration" in your dictionary. "Absolute truths" regarding audio products seems to exist only in your basement and in your head.

John Atkinson's picture
What?

JohnnyR wrote:
John Atkinson wrote:
I looked at the past 15 issues of Stereophile - we published 98 full reviews and follow-up reviews. Of those 98 reviews, 83 were accompanied with a full set of measurements, or 84.5%. So even if not every review includes measurements, the vast majority do, which supports Andreasmaaan's point.

"Reviews" means just that, any item reviewed by your staff. If you think "tweaks" don't qualify then they should be labled as "Opinions" not a review.angle

I am not sure what you mean. You were objecting to Andreasmaan's statement that Stereophile accompanies its reviews with measurements as not being true. I offered the analysis above to show that he was correct.

JohnnyR wrote:
Once more I ask you to read and comment about this link:

http://forums.audioholics.com/forums/loudspeakers/83412-diy-loudspeakers...

You need to consult with your fellow traveler GeorgeHolland, who criticized me about linking to other sites :-)

JohnnyR wrote:
You seem to think DIY can't do anything right in your previous post in answer to [Regadude.] Insulting intelligent people that actually build better speakers than the status quo can produce is beyond being pompus in your case.THAT is what's SAD.

With respect, you are arguing with the voices in your head here. I haven't written anything about DIY speaker designers not being able to do "anything right." What I have said is that a DIY designer, like yourself, doesn't subject his loudpeakers to the scrutiny of a disinterested marketplace, something professional designers do as a matter of course. So the question whether or not DIY designs are superior to commercial designs isn't put under independent scrutiny. It remains unsupported conjecture, as far as I am concerned.

John Atkinson

Editor, Stereophile

GeorgeHolland's picture
Mr Atkinson, you could 

Mr Atkinson, you could  compare DIY against manufactured speakers but of course you won't. Might upset those that can't make good speakers and I'm not talking about the DIY cheeky

Johnny plainly stated that "tweaks" are reviewed in your magazine and online yet they aren't tested, hence you don't test every component under review. You have a reading comprehension problem? How many components reviewed by Jason Serinus have been tested? uh huh, right.

So now you wuss out about commenting on links? That proves you had nothing to say in the first place about it so you shouldn't have opened your mouth.Cop out time for Mr Atkinson.

The only unsupported conjecture on here are your abilities to print honest reviews. Your ability to avoid testing  alot of audio components is well known by now. Very impressive spinning you do on here.wink

John Atkinson's picture
Reading Comprehension

GeorgeHolland wrote:
Mr Atkinson, you could  compare DIY against manufactured speakers but of course you won't. Might upset those that can't make good speakers and I'm not talking about the DIY cheeky

Back in the early 1990s, Stereophile's Corey Greenberg was one of the judges for a DIY loudpeaker competition in San Francisco. There were 2 winning designs and as part of the prize, those 2 speakers were subject to a full set of measurements in Stereophile, published in the March 1992 issue. The speakers' measured performance was good but not great and certainly didn't embarass professional designers.

GeorgeHolland wrote:
Johnny plainly stated that "tweaks" are reviewed in your magazine and online yet they aren't tested, hence you don't test every component under review. You have a reading comprehension problem?

I don't believe so. JohnnyR was wrong, in that we very rarely publish full reviews of tweak products. Of the 98 reviews published in the magazine January 2012 through March 2013, there was just one review of a "tweak," Robert Deutsch on the HiFi Tuning Supreme Fuses in May 2012. ( I don't count the AudioQuest power strip reviewed by Kal Rubinson's review in December 2012 as Kal didn't make any comment on its sound quality, only on its utllity.)

GeorgeHolland wrote:
How many components reviewed by Jason Serinus have been tested? uh huh, right.

The correct answer is none. But that doesn't support JohnnyR's case either, as Jason's reviews are published on the website Secrets of Home Theater and High Fidelity, which has no connection with Stereophile. I hardly believe I am obliged to support reviews of products in competing publications with measurements in Stereophile.

John Atkinson

Editor, Stereophile

JohnnyR's picture
Wow Nostalgia Time Kids

"Back in the early 1990s, Stereophile's Corey Greenberg was one of the judges for a DIY loudpeaker competition in San Francisco. There were 2 winning designs and as part of the prize, those 2 speakers were subject to a full set of measurements in Stereophile, published in the March 1992 issue. The speakers' measured performance was good but not great and certainly didn't embarass professional designers."

Golly "only" 20 years ago and as we all know, nothing new has happened since then to make speaker design any better (Insert BIG sarcasm face here) cheeky Talk about a lame example Atkinson.

Yeah yeah, "full reviews" whatever, Plenty of "little revews" though all the freakin time and all they are , are OPINIONS but you know what? You let your reviewers get away with murdering the intergrity of the audio world with their stupid banter about  "blacker backgrounds,lifted veils and HUGE improvements in the sound" without them having to justify their claims, Pretty slick there pal.

Oh and Jason Serinus "reviews" as posted about the recent RMAF isn't connected to Stereophile? Give us all a break, Your EXCUSES are even lamer this time than usual.

Yep typical Fearless Leader goobley gook. Did you major in Universisty in the double speak of Orwell's 1984? If not then you are gulity of plagiarizing the concept.

John Atkinson's picture
Not making sense

JohnnyR wrote:
Golly "only" 20 years ago and as we all know, nothing new has happened since then to make speaker design any better...

Again you are arguing with the voices in your head, JohnnyR. Of course a lot has happened in the past 20 years, especially the advent of low-cost measuring equipment. But you're missing my point, which is, as I wrote earlier today, that a DIY designer doesn't subject his loudpeakers to the scrutiny of a disinterested marketplace, something professional designers do as a matter of course. You have repeatedy claimed that your speakers are as good as if not better than commercial designs. However, unlike engineers like Kevin Voecks, Paul Barton, Richard Vandersteen, Jeff Joseph, etc, your ability to pay your mortgage and feed your family doesn't depend on your skill as a speaker designer. Their's does, and it makes a difference.

Look, if you seriously believe your speaker designs are fully competitve with commercial designs, email me your measurements. I'll get back to you with my interpretation of what they mean, assuming they are as comprehensive as what I publish with every Stereophile speaker review. Put up or shut up.

JohnnyR wrote:
Yeah yeah, "full reviews" whatever, Plenty of "little revews" though all the freakin time and all they are , are OPINIONS but you know what? You let your reviewers get away with murdering the intergrity of the audio world with their stupid banter about  "blacker backgrounds,lifted veils and HUGE improvements in the sound" without them having to justify their claim...

You're not making sense. "Andreasmaaan" was discussing reviews in the magazine being accompanied by measurements. I was discussing reviews in the magazine being accompanied by measurements. You seem to be discussing something that exists only in your mind. And unlike Professor Dumbledore's quote, that doesn't mean it's real :-)

JohnnyR wrote:
Oh and Jason Serinus "reviews" as posted about the recent RMAF isn't connected to Stereophile?

That was a show report. No-one other than yourself equates a magazine's coverage of a show with its formal equipment reviews. Are you seriously suggesting that magazines shouldn't publish show reports without including a full set of measurement data for each room they report on? Really? There isn't an audio magazine or website that does that.

John Atkinson

Editor, Stereophile

JohnnyR's picture
BLAH BLAH BLAH

Go have another pink drink Fearless Leader.

Me let YOU interpet my frequency response? Don't make me LAUGH. You can't even interpept Wilson't ragged ass frequency response laugh

[usual flames deleted by John Atkinson]

John Atkinson's picture
Making my point

JohnnyR wrote:
John Atkinson wrote:

Look, if you seriously believe your speaker designs are fully competitve
with commercial designs, email me your measurements. I'll get back to
you with my interpretation of what they mean, assuming they are as
comprehensive as what I publish with every Stereophile speaker review.

Me let YOU interpet my frequency response? Don't make me LAUGH.

You make my point for me, JohnnyR. It was a serious offer on my part. Professional loudspeaker designers send out their products for review and for the public scrutiny of possible customers. Amateur speaker designers, such as yourself, are often afraid to let anyone else judge their work.

John Atkinson

Editor, Stereophilee

Regadude's picture
There you go

I have been challenging Johnny tp provide pictures and or the specs of his speakers. He has never met my challenge.

Now the editor of Stereophile offers to look over his data. Johnny again makes up excuses to avoid providing any information on his heavenly speakers.

Big talker...

bernardperu's picture
Contamination

Dear Jon,

What should have been an enlightening discussion of your great lecture has been contaminated by ill-conceived comments. Some individuals have posted comments that have created an environment of nastiness. 

I would seriously urge you to start deleting ill-conceived comments from now on, whether they use flamable language or not. Some people are just turned on by the flames, but others aren't. And those others would much rather focus on the joy of engaging in the music and exchanges related to it.

You do not run a state-owned site but a private one that is likely to become a lot less lucrative (in all senses) if such nasty comments are to become visible.

I am not even pointing out names and we all know who I am talking about.

I am just giving you feedback that comes from an avid reader of Stereophile online. 

Finally, the correction of my use of English was mentioned by one of these individuals. Please allow me to say that English is my second language and it is oxidized. Sorry about that. 

Thanks!

 

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