Auditory Scene Analysis (ASA) explained

Steve Williams said:

Frantz

I'm not a smart engineer like you to prove anyone wrong but you have been in and out of this thread on many occasions by your own volition. All I see John doing is to ask skeptics to think out of the box. Speculation...... perhaps but maybe not. I'm not a neuro scientist but then again neither are you. Beyond that I've been reading this with interest. I have nothing to contribute but not sure you do as well. Curiosity has always piqued my interest Frantz. Without it we would likely be back in the dark ages. Yet I have no idea whether there is fact or fantasy in ASA. Yet I'm an interested reader without casting aspersions nor doubts

When I had just graduated meds school there was a young doctor who had some wild thoughts which were beyond mainstream medicine as we were taught. He was frowned on, shunned, laughed at and even sanctioned by the medical board. He kept doing what he did and challenged people to his way of thinking. Many years later he was proved correct. Is there an analogy in this story? That's up to you to judge and hence my comment re your signature line. If you believe what you put in your signature you might just think a little about either doing what John is asking or if you can't do that then that signature imo is contrary to your beliefs.

Click to expand...

Steve, ASA isn't fantasy - it's a well respected & active area of research & not some idea of mine

What I'm doing is relating how the findings of ASA explain the reports of realism, soundstage clicking into place, air around instruments, etc - it's all about how the brain's processing of the sound better matches the internal model of hearing that we all have - it really is that simple.

What is difficult is teasing out this model - it's not fully unraveled yet

amirm said:

From parallel thread where John indirectly references the book, "Auditory Neuroscience: Making Sense Out of Sound" which as best as I can figure out, he has not read:

...snip

So we learn that ASA is a concept but not fully embraced by research community. Indeed the author goes on to explain how the test that John provided in hearing a tone within noise does not at all need ASA to be explained:
....snip
In other words, the basic science of psychoacoustics is relevant and powerfully explains a lot of what we hear.

That is not to say the concepts behind ASA don't have applicability. The cognitive part of our brain does get involved in interpreting sound. Here is the author again on the effect of vision on what we hear:

...snip

And of course the whole notion of placebo and hearing elasticity is all a function of the brain as opposed to ear.

Cognitive aspects of our hearing does explain for example why we don't hear room reflections as "echos" or why we can hear the signature of a speaker through the same reflections in any room.

What it cannot be used for is random assertions that this and that imagined distortion is an audible problem.

Click to expand...

You were doing so well up to this point. And yes, we use all our senses when perceiving something - mainly because any one sense doesn't provide enough information in it's signal stream to come to a conclusive judgement about what's being sensed (remember we are perceiving the world every second we are awake so quick judgement is essential).

"Random assertions", "imagined distortions", "audible problem" - could you use any more of a loaded sentence? I'm not even going to dissect this - it's getting boring to hear your same hand-waving assertions over & over.

Such claims need to be demonstrated first using controlled testing. Proper references provided. Measurements to back it, etc. Otherwise it is just random chatter in a forum which I ignore, this thread notwithstanding at the moment.

Click to expand...

Sure, Amir, keep telling yourself this if it is the comfort blanket that you need.

FrantzM said:

Steve

Not a problem with your approach. i for one am quite at ease with the fact that we don't know it all and that there aspects of things that are not easily explainable by current knowledge. So I hear you (pun intended) and feel comfortable with your viewpoint. As long as it is admitted that this is speculative, then I am fine. I can live with it. Coloring it as Scientific is what I object to.
Additionally . How can we move forward if all that we do is admit without discussing? Which means coming up with different and contrarian viewpoints? Then JKenny and other will be forced to come up with better ways to frame their points, to convince.

The Schumacher quote, I feel strongly about and try to abide to with (alas) too often spectacular failings: It is about the removal of complexity, not a negation of skepticism, of questioning and of discussing.. Far from that

Click to expand...

You know, I agree with you, Frantz - I find challenges help me to solidify my thinking on a topic & also to express it in a way that better communicates the concepts.

But only if the challenges are specific & logical & show that the person is actually engaged in trying to understand what's being discussed.

Hand waving & generalised objections are not of much value for moving a thread forward or for my honing of my thoughts

FrantzM said:

Could well be microstrip. In the absence of perfect knowledge we are left with .. again ... speculation ... The questioning in itself is healthy unless you just want us to accept anything and everything. You are not preaching that.. Are you?

Click to expand...

Frantz, I'm not asking you to accept anything but I am asking you to engage in a meaningful way that shows you have an interest in the subject & have read & follow the posts.

If people want a good overview of ASA, this 2013 paper does a good job "The what, where and how of auditory-object perception"

Oh & nearly forgot this link to Bregman - a video of one of his talks http://www.music.mcgill.ca/bkn25/videos/Bregman.mp4

FrantzM said:

Against my better judgement and I will live to regret it

John What do you mean that Digital is not bound by the physical world? it is. John.
You don't hear Digital , We only hear analog and what we hear has lower and upper limits and digital won't change that.

Click to expand...

What I meant was that prior to digital audio we were using electro-mechanical means of recording & reproduction - which are bound by the physical world. I thought I had explained this clearly?

WHy is it in the absence of knowledge most people cannot discern digitally manipulated sounds from Analogu, even to the point that some claims (wrongly) to be aqble to derive the quality of a system from a Youtube clip a rather crude digital construct when compare to the SOTA DACS and High Res we have here?????

At the end anything we hear when reproducing music in the here and now is through electromechanical means devices. I read somewhere in a High ENd AUdio forum that an Edison cylinder had a special sound. We had one at home and several 78 and frankly ... ... We are not yet at the point where sounds go directly to our brains through the application of electrodes on our skins or directly at a machine to human purely electrical interface and for that i doubt it would remain in digital form. At this point in time the interface remains electro mechanical and Analog .. We discuss here on WBF about an analog, electromechanical interface!! About electromechanical devices.. That is what our TT, DACs, Cartridge, DAC, Phono Preamp, DAC, R2R, DAC, preamp, SET, AMP, SS, and finally speakers contribute to make of electricity soundwaves for our enjoyment or not

Click to expand...

Hmmm. you are either purposefully pretending to not understand my posts or you really don't - I can't decide which yet?

Another thing .. When you and perhaps most people visit a hall or mirror they may not have been disoriented or annoyed. OTOH, I, have seen people panic in Hall of mirrors.. So your experience is not a rule. Then again we are speculating... we can continue but I fail to see the relevance of ASA to Digital Audio which many here find perfectly acceptable and able to convey all the emotions they need from music , we even have some new converts . I say to them: Welcome !

Click to expand...

Right, I've given you the benefit of the doubt but decided you are not here to actually add anything other than disagreement with me, smoke & confusion - you certainly show no signs of listening to or understanding anything I posted.

I won't be replying to you, Frantz unless you show an intention of engaging in a meaningful way with the thread topic

Actually, I'll deal with the highlighted text "I fail to see the relevance of ASA to Digital Audio" is that not what I just tried to explain in a post in answer to this very same question of yours? So what's the point in coming back with exactly the same question as if I hadn't said anything? This is why I find your attitude here to be disingenuous - you don't wish to engage in what I said, you misunderstand or don't take time to read it & just post the same question again

"which many here find perfectly acceptable and able to convey all the emotions they need from music"

Click to expand...

What is it about this way of thinking shown here & by Amir also - a binary way of looking at things which I suspect is just a debating tactic. I already explained that people can find their system sounds great & couldn't be better, then they discover with some addition it sounds even better, more realistic, etc. Does this mean that they found their system unacceptable prior to its improvement? No it doesn't. So using the argument that "many here find perfectly acceptable and able to convey all the emotions they need from music" is a meaningless as far as this is concerned

FrantzM said:

Steve

It bears to re-read my post I will simply copy part of it here . I believe microstrip to be one. He can correct me. What is acrimonious about it?
My post was against my better judgement. I knew it the second I replied to John post. Out for good!

Click to expand...

Funnily enough, almost everytime you reply to a post of mine you say this & then proceed to show that all you are interested in is posting some sort of criticism of me - you never show any interest in the actual topic being discussed, it's usually a hit & run technique & frankly boringly transparent, Frantz.

Good bye & try to restrain yourself before your next reply to one of my posts & stop yourself in your usual attempts at denigrating me

Ok, one thing that is overlooked in this is that music composers have an inherent sense of how to use ASA to direct attention within musical lines of a piece - this is without knowing ASA, they have just deveoped these techniques over time & practise
Here's one paper which touches on this "The effects of rhythm and melody on auditory stream segregation"
You will have to join researchgate (free) to read the full paper

More on Music perception & a survey of the type of sounds used in perceptual testing. An interesting finding that the sound envelopes used in auditory research may well be skewing the results.
"SURVEYING THE TEMPORAL STRUCTURE OF SOUNDS USED IN MUSIC PERCEPTION"


And finally, Welcome to, Spatio-Operational Spectral Synthesis, https://ccrma.stanford.edu/~mburtner/SOS.html - which is exploration of Bregman's auditory streams as a means being artistically creative!

What's also good for me about questions & challenges on a thread like this is that it also makes me renew some of my reading & also sometimes results in discovering some new reading like this 2017 paper which looks very interesting a sit deals with both auditory & visual scene analysis "Auditory and visual scene analysis: an overview"

I think it's worthwhile to copy the first two paragraphs of the intro here even just for another voice & perspective:

Imagine you are walking on a big busy square. Cars are crossing, pedestrians are walking past and towards you, someone rings their bicycle bell to warn you that they want to pass, you hear people chatting, a taxi driver is shouting and the bell of the nearby school is indicating that school just finished. Meanwhile you note a beautiful coloured tree with its leaves turning orange, because autumn is setting in, and you start to think about your next holiday destination. Our brain is very well equipped to rapidly convert such a mixture of sensory inputs—both visual and auditory—into coherent scenes so as to perceive meaningful objects and guide navigation [1,2], and also to imagine visual and auditory scenes and distinguish them from ‘real’ scenes.

The task of analysing a mixture of sounds so as to arrive at percepts corresponding to the individual sound sources was termed ‘auditory scene analysis’ by Bregman [3]. The task is also known as the ‘cocktail party problem’ [4], which refers to the ability to follow one conversation when many people are talking at the same time. The auditory system has to determine whether a sequence of sounds all came from a single source, and should be perceived as a single ‘stream’ or whether there were multiple sources [5]. In the latter case, each sound in the sequence has to be allocated to its appropriate source and multiple streams should be heard. Similarly, in vision, the visual system has to partition a visual scene into one or more objects and a background, determining which elements in the scene ‘belong’ to which object or to the background. Visual scene analysis research was initially impelled by a compelling idea of Marr [6]. He postulated that the purpose of the visual system is to provide a representation of what is present in the outside world. Although the sensation of seeing complex scenes is seemingly effortless and occurs extremely rapidly, the sensory input is highly complex and dynamic. It takes only a few hundred milliseconds to activate a large cascade of different brain regions, each performing a different transformation of the sensory input [7]. The underlying neural mechanisms of these complex spatio-temporal processes pose major conceptual and methodological challenges for researchers in cognitive neuroscience [8,9].

Click to expand...

A slideshow introductory presentation about auditory & visual scene analysis which some will probably find easier to digest
http://www.phon.ucl.ac.uk/courses/spsci/AUDL4007/Scene_analysis.pdf

Thanks Tao
I hope I have not painted ASA as something more than it is - a theory of how auditory perception works at a deeper level than the psychophysical study of the mechanics of the ear. To me it represents the next layer of the onion in understanding the working of our presceptions.

It is not meant as a study of or explanation for consciousness - that is a far, far more complex question & one that will be extant for decades if not millennia.

You are correct ASA is not the outcome - the outcome is how we respond to, react to the sounds we are perceiving.

How I relate ASA to this hobby is that for me, it explains a lot of the rift between what is heard & what is currently measured - it suggests to me that our auditory perception is a pattern matching analytic technique which we use to make sense of the ever changing sounds from what surrounds us. That might be our playback systems just as much as it might be the bird singing outside my window, at the moment.

What it gave me an insight into (& continues to do) are that 1st order thinking in perception is mistaken - it's often the perceptual effects of some issue that we hear rather than the issue itself. For instance auditory streams (in the sense of ASA) & their importance to what we are perceiving is a crucial understanding to take away from ASA. And it's not as simple as it first appears. You may think a stream is just us following the basoon musical line in an orchestra but what ASA is teasing out is how we are able to follow this musical line - what are the characteristics that we pick out from the nerve impulse signals which tell us to group just those particular elements together as the basoon line (or the massed violins musical line). And it's not a passive analysis, we are constantly predicting what comes next based on our knowledge & experience of how these sounds behave in the world. If the nerve signals (bottom up) don't match our prediction (top down) we quickly formulate a new behaviour model & continue. So this top-down, bottom-up comparison is an ongoing & continual process & we are never in a state of complete certitude about what we are hearing - that's the way it works - it's origins as an alert system are still evident & fully operational.

The implications of this for our hobby are that we are dealing with sound patterns & the closer the sound pattern matches our model of the real world the more realistic we will perceive the playback. So if the fade of a triangle is foreshortened we are aware of this - could be on the recording, could be a dampened triangle but if we hear the same recording on another playback system & it is not foreshortened, we need to consider this & decide which is correct.

If we find we are fatigued by one playback system & not by another, it may well be because our auditory perception is constantly undergoing resets in the prediction that I mentioned above. We are not consciously aware of these resets, they happen below our conscious mind but we may be experiencing the effects of such issues in the sound.

What I find ASA brings to my thinking on audio playback systems is the very concrete notion that it is auditory perception that is the final judge of a system & not simplistic measurements.

I have been promoting the idea for a long time now, that the test signals used for measurements (& indeed for auditory testing) are too simplistic & don't address the whole pattern matching strength that is at the core of auditory processing. I find that such testing is misinformed & misguided & that's also what ASA has opened my eyes to.

I believe there's enough in all of that to be happy with the narrow focus of ASA research & leaving the questions of consciousness for another millenium