Concentrate on only those two areas - if you manage to separate the two areas A and B from the rest of the picture, you can see them as the same colour.
Sure, you can learn to do so, easier still in this case as you know it's a trick question. The point however is to illustrate that our visual (and aural) perception systems are not simple, they rely on heavy signal processing, and are able to be fooled fairly easily.
Couple of years ago I was called on the phone by a guy who asked me if I wanted a line of credit.
I was curious why he called me, so I asked him if he had obtained my stats from somewhere.
The bloke responded that 80 percent has a loan (non-mortgage), he dialed random numbers.
The number of fools on this planet is the summation of idiots with a congenital non-functional brain, the ones who had it switched off, plus those who refuse to turn it back on.
Most, not all. In order to suspect that they are of the same color (or there is an illusion), one must understand how the contrast of the surrounding color will affect the perception. Then there is a way how to see it so it is obvious that they are of the same color.
Yes. Try it. May be not all can do it but I suspect that a few will be able to do it 🙂
Dan Ariely talks about optical illusions among other interesting brain topics here: https://www.ted.com/talks/dan_ariely_asks_are_we_in_control_of_our_own_decisions
The continuous stare works fairly easily on this one. Diana Deutsch did this for audio maybe more relevant, a very interesting set of audio illusions. Cool she has them on a site to play and read the descriptions.
http://deutsch.ucsd.edu/psychology/pages.php?i=201
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Scott, thanks for the link.
Getting back to what people can hear and what is imagined, as far as I can tell, most of the research to date, such as described AES publications, did not take into account a number of things that have only recently been discovered about aural cognition. We do know people very greatly in some respects, such as how pitch is perceived at a very basic level.
I am not aware of anybody looking into how perception of distortion is perceived at a similar very basic level, but I suspect when somebody gets around to it we will also find a lot of variation.
Besides variation, its possible a better understanding of how peeking or looking might function as some type of cue to focus listening attention in a way to enhance perception of very weak patterns buried in noise. Obviously, this is a tricky area, since we know about the existence of imagination based errors (aural pattern recognition false positives), and we also know that peeking can be used for cheating. Anyway, I have some more thoughts about how a postulated cuing mechanism might function similarly to certain cued visual recognition abilities under difficult visual conditions. But for now, I will leave off here.
Getting back to what people can hear and what is imagined, as far as I can tell, most of the research to date, such as described AES publications, did not take into account a number of things that have only recently been discovered about aural cognition. We do know people very greatly in some respects, such as how pitch is perceived at a very basic level.
I am not aware of anybody looking into how perception of distortion is perceived at a similar very basic level, but I suspect when somebody gets around to it we will also find a lot of variation.
Besides variation, its possible a better understanding of how peeking or looking might function as some type of cue to focus listening attention in a way to enhance perception of very weak patterns buried in noise. Obviously, this is a tricky area, since we know about the existence of imagination based errors (aural pattern recognition false positives), and we also know that peeking can be used for cheating. Anyway, I have some more thoughts about how a postulated cuing mechanism might function similarly to certain cued visual recognition abilities under difficult visual conditions. But for now, I will leave off here.
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We also know that (for most people, at least) pitch perception can become more accurate with training. If one takes some music lessons and plays a musical instrument regularly for a few years, one will almost certainly end up with a better sense of pitch.
We know that increasingly more and more distorted and discordant sounds have been incorporated into music over the years. A few centuries ago, only perfect octaves were considered consonant. Then the perfect fifth was given the okay. A long time after that, not-quite-so-consonant thirds were incorporated into music.
Then came more and more discordant chords, from major sevenths to plain old (dominant) sevenths, then ninths, elevenths, etc. By the time jazz was in its heyday, flat-13 chords were considered musical (though still played on undistorted acoustic instruments, or "clean" guitar.)
Such chords would have been considered intolerable a few centuries earlier - far too harsh, far too much discord.
By the time we got to Jimi Hendrix and his Fuzz-Face, we had added harmonic distortion to discordant harmony; millions of people had trained their ears to tolerate vast amounts of harmonic distortion, and even to find it attractive.
But we didn't stop there; we wound up with metal, and it evolved into harsher and harsher guitar tones, until the guitars in some recent bands (Evanescence, say) now sound to me like power tools grinding on a rusty corrugated-metal roof. But many younger people love those harshly distorted sounds.
My hunch is that people who've trained themselves to enjoy large quantities of heavy harmonic distortion, also, in the process, become insensitive to small amounts of harmonic distortion; literally, they no longer notice it, meaning that they have now become unable to detect small amounts of harmonic distortion.
I've tested this hypothesis on a few young people, by gradually adding distortion to my electric guitar until they finally notice it. Usually it takes quite a lot of distortion (to my perception) before they do notice it.
Obviously my aging ears are less capable than those young people's. But my brain is trained to find heavy harmonic distortion unpleasant, and so I notice much smaller amounts of it, than they do.
I will add that I hear harmonic distortion from most, if not all, electric guitars with conventional magnetic pickups, even when the amp is clean as clean can be. The nonlinear magnetic field above the guitar pickup is the major cause of this, and the effect is usually not subtle.
Yet, many people don't seem to hear this at all these days, though I suspect it was part of the reason so many adults hated electric guitars fifty or sixty years ago. It was harsh to that generation, but most of us now don't hear that harmonic distortion (harshness) any more - we can't perceive the same amount of harmonic distortion our grandparents did.
So yes, I would say that one's perception of harmonic distortion is quite strongly influenced by one's own musical experiences. If you love the sound of the guitars in Evanescence, you probably find Santana's guitar tone so bland as to be boring, and quite possibly, you won't really notice 10% of low-order harmonic distortion. And what on earth will you make of the sound of a classical English Horn in a nearly three-hundred-year-old piece of music? What was a rousing call to arms then may sound like a lullaby to you now.
As for the original thread topic, the answer is "Nothing. Ever since the NE5532, almost nothing is wrong with op-amps for audio; in any reasonable application, you can't really audibly improve on it ."
This guy has some interesting write-ups about op amps, including discussion of some of the lunatic-fringe voodoo beliefs about them: NwAvGuy: Op Amps: Myths & Facts
-Gnobuddy
Level of exposure/conditioning should not be confused with learning, imho.
(autonomic-sympathetic versus voluntary-parasympathetic)
Sometimes the word learned is used more broadly: http://www.cell.com/current-biology/pdf/S0960-9822(99)80306-6.pdf
For sound (taken from http://artsites.ucsc.edu/ems/music/tech_background/te-03/teces_03.html ):
We have seen that sound of a particular waveform and frequency sets up a characteristic pattern of active locations on the basilar membranes. (We might assume that the brain deals with these patterns in the same way it deals with visual patterns on the retina.) If a pattern is repeated enough we learn to recognize that pattern as belonging to a certain sound, much as we learn a particular visual pattern belongs to a certain face. (This learning is accomplished most easily during the early years of life.) The absolute position of the pattern is not very important, it is the pattern itself that is learned. We do possess an ability to interpret the location of the pattern to some degree, but that ability is quite variable from one person to the next. (It is not clear whether that ability is innate or learned.) What use the brain makes of the fact that the aggregate firing of the nerves more or less approximates the waveform of the sound is not known. The processing of impulse sounds (which do not last long enough to set up basilar patterns) is also not well explored.
For sound (taken from http://artsites.ucsc.edu/ems/music/tech_background/te-03/teces_03.html ):
We have seen that sound of a particular waveform and frequency sets up a characteristic pattern of active locations on the basilar membranes. (We might assume that the brain deals with these patterns in the same way it deals with visual patterns on the retina.) If a pattern is repeated enough we learn to recognize that pattern as belonging to a certain sound, much as we learn a particular visual pattern belongs to a certain face. (This learning is accomplished most easily during the early years of life.) The absolute position of the pattern is not very important, it is the pattern itself that is learned. We do possess an ability to interpret the location of the pattern to some degree, but that ability is quite variable from one person to the next. (It is not clear whether that ability is innate or learned.) What use the brain makes of the fact that the aggregate firing of the nerves more or less approximates the waveform of the sound is not known. The processing of impulse sounds (which do not last long enough to set up basilar patterns) is also not well explored.
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I thought this thread was about opamps.
Why don't we talk about parapsychology. I mean people who believe opamps are no good must also believe in ghosts, right?
Why don't we talk about parapsychology. I mean people who believe opamps are no good must also believe in ghosts, right?
Is parapsychology concerned with beliefs? What would be the relevance of beliefs to this thread? Or were you making some kind of a joke here?
Wrong.
Also, many people who say that different opamps sound different would not also say all opamps are no good.
If you are talking about the psychology and physiology of hearing then you're taking the position that there is nothing to talk about or find to separate the sound of any two opamps - and certainly not any of the "modern" high performance opamps.
You mean the opposite? The higher the PSRR the greater the isolation between power supply and the rest of the circuit.
Jan
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