Fas42’s Stereo ‘Magic’

[fas42]

Err, I read that as a simple confirmation of what I'm stating. The prior section of that paragraph reads,

 

Quote

Stereo techniques may also be explained as a consequence of summing localization,
whereby a single auditory event is perceived in response to two sources radiating coherent
signals (Blauert, 1983). When either one of the sources radiates a locatable signal, the
auditory event appears at the location of the source. When both sources radiate the same
signal in some amplitude proportion, a single auditory event is perceived at a location
between the two sources, even though the actual ear signals are not entirely consistent with
this perception.

 

Those two sources are the two speakers, and here the author is describing the classic "phantom image" behaviour.

[STC]

4 hours ago, fas42 said:

And something else found, "3-D Audio Using Loudspeakers", a thesis from 1997: https://dspace.mit.edu/bitstream/handle/1721.1/29134/38271570-MIT.pdf?sequence=2

 

A quick glance through, this is full of "old school" thinking, on what is required ... but, at the end, in the discussion section, this caught my eye:

 

 

My emphasis added ... and in fact the "should" turns into a "does" - when a playback system is sufficiently competent. This is when the "magic" switches on - as far as the brain is concerned, it's now, "natural listening".

 

Natural listening is not stereo. This thesis was about attempt to reproduce 3D sound with loudspeakers. The closest what this thesis was describing is BACCH of Princeton University, that is, with head tracking. 

 

What you quoted ( produced below) was a reference to binaural reproduction with loudspeakers with XTC and head tracking. Unless, your magic have both of them incorporated then it is still stereo that largely dependant on intensity difference for the creation of the phantom image that is limited between the two speakers. 

 

They are not the same. The thesis is about binaural sound with loudspeakers. Your magic is about stereo sound. They are not the same. 

 

 

1 hour ago, fas42 said:

Err, I read that as a simple confirmation of what I'm stating. The prior section of that paragraph reads,

 

 

Those two sources are the two speakers, and here the author is describing the classic "phantom image" behaviour.

 

[fas42]

What I would call "natural listening" is when one's hearing reacts to auditory stimuli in the same way as it does to live sounds - which is what the part I quoted was referring to, as I read it.

 

By contrast, nearly all audio playback is immediately identifiable as such; it doesn't "fool you" - it always sounds 'unnatural'; it may sound impressive, may do some things brilliantly - but if the sound was coming from behind a curtain, and you insisted that the source was a live performance, all the others listening would look at you as if you had a screw loose - "it's obviously a hifi, for pete's sake!".

 

The "magic" is in getting a setup to create that illusion - and if it does it correctly, then the illusion remains no matter where you are, say, in the house.

[STC]

2 hours ago, fas42 said:

What I would call "natural listening" is when one's hearing reacts to auditory stimuli in the same way as it does to live sounds - which is what the part I quoted was referring to, as I read it.

 

 

The term "natural listening" is defined clearly in your reference.  You are taking another definition used in the thesis and giving a different meaning.  Natural listening is listening with our ears with all the HRTF intact. 

 

Quote

 

By contrast, nearly all audio playback is immediately identifiable as such; it doesn't "fool you" - it always sounds 'unnatural'; it may sound impressive, may do some things brilliantly - but if the sound was coming from behind a curtain, and you insisted that the source was a live performance, all the others listening would look at you as if you had a screw loose - "it's obviously a hifi, for pete's sake!".

2

 

The thesis explained why you could always tell why something is not natural when listened to stereo. The brain is confused all the time in fixing the correct localization cue.

 

I am confining to the frontal stage sound only. Formats, such as 5.1, are not really natural sound despite the ability to render surround from 360 degrees. 

 

Quote

 

The "magic" is in getting a setup to create that illusion - and if it does it correctly, then the illusion remains no matter where you are, say, in the house.

 

That's true. The thesis was addressing the errors caused by stereo (among others) and how to solve them.  An error that is so great in stereo that the natural time difference cue is discarded for localization.  Stereo causes a different location to the brain which renders it to be unnatural, and you could always tell that is not real.

 

Please read the full thesis or at least part where it talks about the flaws in stereo which makes it impossible to reproduce 3D sound with stereophonic.

[fas42]

Okay, reading further,

 

Quote

The central idea (strictly speaking, the "thesis") of this dissertation is that the equalization
zone of a crosstalk cancellation system can be steered to the position of a tracked listener,
and that doing so greatly improves the simulation of a spatial auditory scene.

 

IOW, a tracking system, akin to the Symth Realiser headphone setup - so that the ears receive the 'right' information as one moves around, to perceive spacious sound - if one accepts that crosstalk cancellation is necessary for this type of 3D effect.

 

My point is that one's internal, own head processing is capable of resolving the supposed cues conflict between the primary sources of sound in the room, the speakers, if the quality of the information is sufficient. That is, the human hearing system, at least for some indviduals, has its own, 'inbuilt' crosstalk cancellation 'algorithms', which can be triggered when the detail in the sound heard is at a certain level.

 

I accept that there will be people for whom this can never happen, because of "how their brains are wired" - but the benefits for everyone else are great, if they pursue this route.

 

I will note here, that I have proposed in a much earlier post doing an experiment where one hears live sound through two openings in a wall that mimic the location of speakers - and ask what the listeners perceive. As is usual in the audio world, this thought garnered zero response - doing experiments to find out things should always be left to someone else to do, .

[fas42]

Having just been made aware of the "precedence effect", I found this update of Blauert's work, "The precedence effect", by Litovsky et al: https://s3.amazonaws.com/academia.edu.documents/45002474/The_precedence_effect20160422-32310-1o1mj6c.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1542601798&Signature=IxpbFiW1JUtxyWM994qv2RJOaa4%3D&response-content-disposition=inline%3B filename%3DThe_precedence_effect.pdf.

 

I particularly note in the conclusion:

 

Quote

While the motivation for many of the experiments is partly rooted in our desire to understand how the auditory system processes multiple arrays of directional cues in reverberant spaces, many of the studies do not directly address ‘‘real-world’’ issues. In fact, the precedence effect as an auditory phenomenon has little to do with realistic acoustic environ-ments. However, we believe that the work in this area can be
instrumental in motivating future work in more realistic sce-narios, and that it offers a unique window into the auditory system, by viewing auditory processes through human per-ception, animal behavior and physiology, as well as devel-opment. It is probably only through the combined efforts of these various approaches that a full theory of precedence will evolve and useful models will be developed. Since this topic of research is dynamic and ongoing, our paper represents a mere snapshot that will clearly need updating as the field progresses.

 

IOW, to be continued ...

[PeterSt]

2 hours ago, fas42 said:

IOW, to be continued ...

 

After 20 years ?

[fas42]

That is, research into the precedence effect, meaning how our hearing reacts to reverberation in the listening space 'confusing' what we hear, still doesn't have all the answers - more investigation is needed.

[STC]

On 11/18/2018 at 12:22 PM, fas42 said:

IOW, a tracking system, akin to the Symth Realiser headphone setup - so that the ears receive the 'right' information as one moves around, to perceive spacious sound - if one accepts that crosstalk cancellation is necessary for this type of 3D effect.

 

You are not alone with this misconception as I find that even those with acoutics field  background and 3D research confused with object based surround and plain binaural hearing. 

 

Symth is headphones sound that feel like listening to multispeakers setup. You do not feel the inside the head and fixed stage with headphone listening with Smyth. 

 

Surround sound and 3D sound are not the same but surround can bring a reasoable realism conpared to plain stereo. 

[STC]

9 hours ago, fas42 said:

Having just been made aware of the "precedence effect", I found this update of Blauert's work, "The precedence effect", by Litovsky et al: https://s3.amazonaws.com/academia.edu.documents/45002474/The_precedence_effect20160422-32310-1o1mj6c.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1542601798&Signature=IxpbFiW1JUtxyWM994qv2RJOaa4%3D&response-content-disposition=inline%3B filename%3DThe_precedence_effect.pdf.

 

I particularly note in the conclusion:

 

 

IOW, to be continued ...

 

This paper was an attempt to distinguish other effect to explain the precedence effect better. Bluaert referred to this paper but nowhere the conclusion aboit the research about discovering an unknown. 

[fas42]

So, the precedence effect is fully understood, currently ... hmmm. Found "Reflection properties infuencing the precedence effect", published in March, 2018: https://www.researchgate.net/profile/Florian_Wendt2/publication/325147212_Reflection_properties_influencing_the_precedence_effect/links/5afaca11458515c00b6c327a/Reflection-properties-influencing-the-precedence-effect.pdf.

 

From that paper,

 

Quote

Very often the surface of a wall is not completely smooth
but contains regular or irregular corrners, bumps or other
projections. Depending on their sizes compared to the
wavelength, the reflected sound field can be scattered. In
this case we speak of a diffusely reflecting wall yielding
a spatial and temporal widening of the reflection. Only
little is known on the influence of diffuse reflections on the
precedence effect and to the authors' knowledge, there is
only one study considering temporal diffusion.

 

IOW, in real world listening environments there is a paucity of knowledge about the precedence effect, still.

[fas42]

I always keep my eye out for gear that in raw form gets as much right as possible - and have just discovered the Nuprime brand. The latest Evolution One mono amplifiers, using class D technology, appear to tick every box; going by the comments of those who have heard them - this appears to be as good an example of competent electronics circuitry as any as I have come across, with the advantage of efficiency to boot; certainly would on the top of a list of components that I would choose from, if I couldn't fiddle with the insides.

 

A quote from a person on first exposure,

 

Quote

"Normally, when I listen to a new amplifier, I can find something to criticize however, with the Evo One amplifiers I can't find a single thing to comment on. They have this uncanny ability to recreate live music that other amplifiers - even amplifiers that are significantly more expensive than the Evo One, just can't achieve. It's like everything I've experienced in the last thirty-seven years as an audiophile was flawed somehow and now that I've heard the new Evo One I can't listen to anything else without noticing it's inherent flaws. With the Evo One amplifiers, I get the sense that I'm hearing the live event for the very first time. The level of realism is extraordinary."

 

Yep, that's what it's about ...

[fas42]

One of the 'gurus' in the audio game is posting in another forum, and his very first post there is a good description of some of the qualities of "competent sound", https://www.audiosciencereview.com/forum/index.php?threads/bacch4mac-pro-edition-a-report.2373/post-75283.

 

Note this is doing the trick using some processing technology called VMAX - deliver "surround sound" from 2 speakers, by creating virtual cues from the source material. Bingo! It worked well, and created an immersive listening environment .

 

Now, the same thing can be done, 'raw', by making sure that those cues which are always embedded in the recording material can be clearly heard - the same, internal to the brain processing is making the experience happen, except that in the VMAX case extra spotlighting is added, to compensate for the loss of detail in normal SQ reproduction.

[fas42]

Okay, I've been reading through all Toole's posts on that forum, to get a sense of how his thinking may have evolved, as of right now. Reasonable up to now, but this one needs commenting on, https://www.audiosciencereview.com/forum/index.php?threads/genelec-on-audio-science.3110/post-80461.

 

To summarise, he believes that the "signature" space of the listening space can't be overridden by that of the recording, if the system is purely stereo. Having experienced the converse of that for decades, with multiple setups, this is clearly not correct, at least for a percentage of listeners.

 

He says, "Evidence to date is that in such a situation of superimposed spaces, the larger one wins." ... No. The one that wins is that which has the greatest 'intensity', which is sending the strongest, highest integrity cues to the hearing system. The brain slots into the space which is the "most interesting", ignores the "boring one". The audio playbacks used for testing these ideas, by the researchers, are not "good enough"; they're generating the "boring" sound, so, they don't win.

 

And also, he focuses on the low frequency spectrum; which to me is the giveaway. Competent sound is all about the midrange and treble; bass just goes along for the ride, to fully fill out the picture. Low frequency resonances? I have almost no idea what this is, because subjectively they don't exist for me - I would need to be shown on a sub-par rig what they get so excited about, here - unless they mean that awful subwoofer blubbering I occasionly come across, grotesquely 'fake', offputting 'bass'.

[fas42]

Noting two audiophile myths currently being discussed or reacted to on AS - one 'objectivist', and one 'subjectivist'.

 

The former is that if one characterises a cable with conventional testing gear that we then know all that is relevant to whether a particular cable will be beneficial, or at least do "no harm" in a rig. Which ignores the situation where the cable having 'peculiar' properties may compensate for or attenuate some audible artifact generated by the nature of the overall setup - the cable effectively "filters out" what is disturbing to the listener - and hence is a plus - in some rigs, possibly!! Of course, the 'correct' solution is take away the need for a cable "bandaid", by sorting out the underlying issue.

 

In the 'subjectivist' camp is the belief that a good system separates good from bad recordings - makes the latter more and more unlistenable to, and in fact one 'knows' that one is going in the right direction, because the bad ones get more and more ugly ... oh, dear!! I have heard these sort of rigs, and they are an abomination! Impossible to live with, because only the most scrupulously, plainly recorded albums can be listened to, with "pleasure".

 

There is a 3rd road, where one concerns oneself with 'unconventional' aspects which affect the integrity of a playback system; and which if fully followed through on allows all recordings to show of their best - this is the way of, well, "stereo magic" .

[fas42]

A key exchange of thoughts in another forum ...

 

Quote

my friend has a piano and from time to time I come to him to listen to him play it. It is a true concert piano and its sound so much dominates the room with energy that I cannot possibly imagine speakers coming even close to it. Mine cerrtainly don't.

 

Quote

I'm not unfamiliar with the power of the piano. But listening thru a doorway from outside it was fully believable you'd step inside to find a piano. I heard it several times and for more than just a minute.

 

Quote

Sure, speakers can do that sometimes when you're not in the same room. Unfortunately, as soon as you step in the magic is gone.

 

This is the challenge ... to make the magic happen even directly in front of the speakers. This is what happened to me over 3 decades ago - and the effort to get a rig to the necessary level always bestows its reward, when the presentation finally delivers.

 

"Sound from the speakers dominating the room with energy" is what you get - it's a buzz that makes listening to a setup working at less than such a standard, a pretty feeble alternative ...

[fas42]

The NAD and Sharp combo haven't been run for a bit, the weather has been stinkin' hot, and the player is feeling its age, and refuses to play ball after a while, if it gets too warm.

 

Now, sanity returns to the temperatures ... a switch on, and from cold played this, https://www.discogs.com/Various-Back-To-The-Forties/release/9256966 - a regular 'test' CD that I have used for decades. And was reminded straight away why I am very partial to this setup - it's "musical" from the word go; the sins are of omission - proverbial, "foot-tapping quality" from these needledrops.

[audiobomber]

On 10/12/2018 at 6:24 AM, Blackmorec said:

Is Frank genuinely onto something or is he just a misguided nuisance consuming forum bandwidth?  

I'm going with the bolded text. 

[fas42]

Multiple people have experienced, got onto this type of sound at times; and most have come across a rig delivering 'special sound' once or twice, at odd moments - and have dismissed it as "one of those things"; come up with a whole suite of explanations for why it sounded like that ... and moved on. I'm the person who didn't move on; and decided to find out, well, "what was going on" ...

 

Inertia, a desire to go along along with the pack, group thinking, are powerful forces - especially when the "unusual behaviout" occurs rarely, and only after a lot of highly focused effort. Trying to pretend something isn't there, just so you can feel comfortable with your standard set of beliefs, is very human - but prevents true progress from happening; human history is littered with instances of this.

 

I have no desire to fit under the umbrella, along with everyone else, for a jolly group hug - if something is there, well, it's there.

[fas42]

I was thinking during the last day or so about the home theatre Car Door Slam trope - that powerful Whumph! when each character gets out of a standard sedan, and just closes the door ... this is a sound that has absolutely nothing to do with reality; get a truck door and slam it shut with all your force, so that the window glass cracks - followed by your skull cracking, as the truck owner rewards you for that feat - it still won't sound anything like the HT BPB - Big Pr!ck Bass - version.

 

Part of the https://tvtropes.org/pmwiki/pmwiki.php/Main/TheCoconutEffect cavalcade, it overlaps with a lot of audiophile beliefs about how home audio should sound - if a system doesn't push certain buttons, it has to be wrong, no matter how much it's getting right. Which is a shame ... because low cost equipment can do brilliantly well, so long as its limits are not exceeded.

 

The important point is that excellent value for money equipment can climb out of the bin juice at the bottom of the audio uncanny valley, something that many expensive rigs can pick up the scent of far too easily - very few do so, because it doesn't benefit the manufacturers, whose client have no such expectations; and the alternative route means concerted effort on the part of those interested, who wish to DIY such a combo.

 

The car equivalent is already well understood ...

 

 

[fas42]

Looks promising ... https://www.purifi-audio.com/

 

Quote

From Peter Lyngdorf’s Facebook page:

“Today we show the prototype Lyngdorf 8 x 400 Watt class D amplifier based a new patented class D amplification technology which is the brainwork of my co-founders of Purifi Audio, Bruno Putzeys and Lars Risbo. This is the first of any class of audio amplifier which is completely indifferent to frequency, level and impedance variations. The actual performance is difficult to measure due to limitations to even the best test equipment (AP555). But we are specifying max 0,00015% THD+Noise, at ANY frequency 20-20KHz at 100 W/4 ohms. Intermodulation distortion WAY below any other technology. Notice the output impedance - scaled in micro Ohm!”

 

[audiobomber]

2 hours ago, fas42 said:

Looks promising ... https://www.purifi-audio.com/

Will you be buying one?

[fas42]

No ... but it's a good sign that amplification that just does the job, without effort or requiring extra attention, is going to become more and more the standard - and cheaper.

[gmgraves]

On 11/17/2018 at 2:00 PM, fas42 said:

What I would call "natural listening" is when one's hearing reacts to auditory stimuli in the same way as it does to live sounds - which is what the part I quoted was referring to, as I read it.

 

By contrast, nearly all audio playback is immediately identifiable as such; it doesn't "fool you" - it always sounds 'unnatural'; it may sound impressive, may do some things brilliantly - but if the sound was coming from behind a curtain, and you insisted that the source was a live performance, all the others listening would look at you as if you had a screw loose - "it's obviously a hifi, for pete's sake!".

 

The "magic" is in getting a setup to create that illusion - and if it does it correctly, then the illusion remains no matter where you are, say, in the house.

The illusion doesn't rely 100% on the playback equipment either. The source is just as important. It's a given that even the very best audio systems, even those costing close to six figures are far from perfect.They might be very low in distortion, but there is distortion there, nonetheless. Audio systems (and recordings) all suffer when asked to reproduce, realistically, a full symphony orchestra. Whatever illusion that such a system weaves with lesser music collapses when asked to do a full symphony in full song (like the climax of Resphighi's "Pines of Rome"). But that doesn't mean that a well set up home audio system can't give glimpses of reality with the right recordings and the right kind of music. If you play one of our friend Mario Martinez' hi-rez piano recordings (like Angel Cabrera Plays Debussy) and it sounds like the Steinway piano is in the room with you (and not coming from a couple of loudspeakers) then you can rest assured that your system is very neutral and very low in coloration. This is the scale of playback that modern equipment can handle in a most realistic way. The piano is correctly recorded (and thus is not as big as the room) and the dynamics and frequency range of the Steinway are well within the confines of what modern audio can do. The sound will be satisfying because it actually fulfills the promise of stereophonic High-Fidelity; it brings the performance right into your listening room. But play a well recorded symphonic recording and it will fail the you-are-there "palpability" test. A home audio system, just cannot realistically bring the Boston Symphony into your living room, and I seriously doubt if it ever will. We have to be content that we are listening to such an ensemble through a large, open, picture window. I.E. it can sound good, but it never quite crosses that threshold from sounding like a good recording to sounding like either there's a symphony orchestra in your listening room, or that you have been transported to some concert hall where the performance is taking place. 

[Allan F]

3 hours ago, gmgraves said:

A home audio system, just cannot realistically bring the Boston Symphony into your living room, and I seriously doubt if it ever will.

 

Agreed. Who has the room to bring the Boston Symphony into their living room?