Subjective sound bokeh - interesting analogy.

[dualazmak]

It's not the main direct sound that we want blurred, it's the reflections. In other words, we don't want specular reflections, we want diffuse reflections. It creates an ambience that we find pleasing. At least, that's what I take from what the OP meant.

And yet we prefer a certain amount of reflected sound in our systems, even though it somewhat "blurs" the pinpoint imaging created by the direct sound....

Pretty much no one likes to listen in an anechoic room with no reflections - which is what is required for perfect pinpoint sharp imaging to the max!

You two and me, as well as the OP, are having/sharing similar perspectives/impressions on so-called "sound bokeh" in our own listening environment, I assume.
And, in my recent post #124 on the thread "Omnidirectional loudspeakers ?", I would like to have thoughts and comments from Dr. Toole and other people on my "sound diffuse/dispersion" approach.

Furthermore, as I referred in that post, I once wrote here #502, in January 2022, on my project thread as follows;

>At present, since I like the listening feeling as if I am sitting on the best S-class center seat in Concertgebouw Amsterdam, I do not like to have my SWs (subwoofers) just beside me at my listening position; even with the "complete and perfect" time alignment of SPs I achieved, the orchestral big drum sound should be coming from the stage direction in front of my eyes and ears!

>Of course, I know well that in real Concertgebouw Amsterdam (I have been there several times), I hear the entire hall tone (including the reflections, resonances, standing waves) from all the directions surrounding me, from behind, above (ceilings), side (side walls) and floor. This is the main reasons that I insists we need suitable and preferable reverberations also in our home audio listening room which somewhat "simulates" the real hall tone, but of course never to be perfect.

>In my listening environment, I have fairly nice and big open spaces/rooms behind the SPs and also behind my listening position, and these (I designed so when I built my present house) are very nice for the room acoustics I fully enjoy now. Fortunately, many of the semi-professional audio enthu friends well agree me on the nice acoustics even in my present setup.

Yes, I fully agree with your point of "no one likes to listen in an anechoic room with no reflections".

 

[FrantzM]

No,

So is your starting point, listening in an anechoic space?

The signal/musical event should come out of the transducers as unmolested as technologically possible... from there, we find ways to mitigate not eliminate, the effect sof the room... We know that some of the effect of the room are desirable, and this at, even a physiological level. We have the technology for the mitigation of some of the deleterious effects, by means that could be purely mechanical (Physical Room treatment), electronics/software (DSP) or even hybrid .. Knowing that most of the nefarious effects reside in the lower portion of the audible spectrum, we can limit the "treatment" to that range leaving the rest untouched ...

A bit off-topics
As I mentioned it, Humans can get used to almost everything.. but I no longer can comprehend how one can get good bass reproduction clean, that is, extended, of sufficient reach (in frequencies) and level (SPL), smooth frequency response, and correct decay without the use of some DSP or at the very minimum EQ... makes you wonder how an entire segment of audiophiles came to hate DSP... It is something that has come to me, Having listened with my modest system as reference, to some mega dollars system recently .. In most of those HEA systems, some costing more than a decent size house in major US markets, the bass performance was laughable ...

 

[ahofer]

It's not the main direct sound that we want blurred, it's the reflections. In other words, we don't want specular reflections, we want diffuse reflections. It creates an ambience that we find pleasing. At least, that's what I take from what the OP meant.

Are they 'blurred', though? Aren't they just lower in amplitude? As you say, we diffuse them, but doesn't that just reduce the amplitude of that reflection at any particular position? Or is there some wave effect of diffusion that I'm not considering?

 

[Keith_W]

Are they 'blurred', though? Aren't they just lower in amplitude? As you say, we diffuse them, but doesn't that just reduce the amplitude of that reflection at any particular position? Or is there some wave effect of diffusion that I'm not considering?

Maybe this is taking the analogy a bit too far. In photography, there are two ways to make the subject stand out over the background.

1. The subject is in focus and thus appears sharper than the background. The more blurred the background is, the more the subject stands out.
2. The background is given different treatment to the subject - it can be darker or brighter (high key), more desaturated, less contrast, etc.

It is the opposite of camouflage, where the object tries to blend into the background.

I suppose, when it comes to audio, we want the direct signal to be as clear as possible and the ambience to be BOTH sufficiently attenuated and diffuse.

 

[dualazmak]

Are they 'blurred', though? Aren't they just lower in amplitude? As you say, we diffuse them, but doesn't that just reduce the amplitude of that reflection at any particular position? Or is there some wave effect of diffusion that I'm not considering?

Well, I assume we/you need our/your own intensive subjective assessment through actual experiments, in our/your own acoustic environments.

Otherwise, we will be easily trapped by endless and downward discussion spirals, whatever "term", blur or bokeh or diffusion or dispersion, we would use. I mean there can be no rational objective "generalization" discussion on our present topic.

Let me suggest you just one "extreme" example case of audio experiment.

If you have (or you can affordably introduce) highly efficient metal horn super-tweeter to cover ca. 8 kHz to 25 kHz singing together with your tweeter, I would recommend you trying wide-3D reflective dispersion of the super-tweeter sound by using hard-random-surface material in various relative gains against tweeter, as well as in various physical positioning settings, like I have done it.

Spoiler

- A new series of audio experiments on reflective wide-3D dispersion of super-tweeter sound using random-surface hard-heavy material:
Part-1_ Background, experimental settings, initial preliminary listening tests: #912
Part-2_ Comparison of catalogue specifications of metal horn super-tweeter (ST) FOSTEX T925A and YAMAHA Beryllium dome tweeter (TW) JA-0513; start of intensive listening sessions with wide-3D reflective dispersion of ST sound: #921
Part-3_ Listening evaluation of sound stage (sound image) using excellent-recording-quality lute duet tracks: #926
Part-3.1_ Listening evaluation of sound stage (sound image) using excellent-recording-quality jazz trio album: #927
Part-4_Provisional conclusion to use Case-2 reverse reflective dispersion setting in default daily music listening: #929

I believe that you yourself will subjectively find/hear various sound perspectives through this simple actual experiments in your present room acoustic environments; some of the sound perspectives would be completely unacceptable for you, some would give almost no change, and some would give excellent improvements, the determination/decision is totally up to your listening preference, whatever "term", blur or bokeh or diffusion or dispersion, you would use for rationalization of your subjective results (pros or cons).

You may share "your" experimental settings and subjective results with other people (again I have done it), but it would never to be the objective generalization for all the people, since we always have different acoustic environments.

 

[dlaloum]

No,


The signal/musical event should come out of the transducers as unmolested as technologically possible... from there, we find ways to mitigate not eliminate, the effect sof the room... We know that some of the effect of the room are desirable, and this at, even a physiological level. We have the technology for the mitigation of some of the deleterious effects, by means that could be purely mechanical (Physical Room treatment), electronics/software (DSP) or even hybrid .. Knowing that most of the nefarious effects reside in the lower portion of the audible spectrum, we can limit the "treatment" to that range leaving the rest untouched ...

A bit off-topics
As I mentioned it, Humans can get used to almost everything.. but I no longer can comprehend how one can get good bass reproduction clean, that is, extended, of sufficient reach (in frequencies) and level (SPL), smooth frequency response, and correct decay without the use of some DSP or at the very minimum EQ... makes you wonder how an entire segment of audiophiles came to hate DSP... It is something that has come to me, Having listened with my modest system as reference, to some mega dollars system recently .. In most of those HEA systems, some costing more than a decent size house in major US markets, the bass performance was laughable ...

Some mythologies go back a long way ... in the early days of DSP - the mid 1980's - there were some attempts to do fairly fancy things - but with the technology in its infancy, almost invariably, really good basic stereo setups, ended up sounding better than than DSP and EQ (EQ at the time was pretty much universally analogue)

What Dirac ART does for my setup, was simply not possible 10 years ago, let alone 40 years ago...

But the old attitudes die hard.... and have been mythologised!

 

[RexrothPigeon]

hey the toyota bokeh

makes you wonder how an entire segment of audiophiles came to hate DSP

age-related hearing decline + belief perseverance

 

[Roland68]

Der Begriff „Bild-Bokeh“ beschreibt, wie die Unschärfe im Hintergrund eines Bildes zur Gesamtwahrnehmung des Bildes beiträgt.
Mit meinen alten 500/8-Spiegelteleobjektiven erhalte ich ein schlechtes Bokeh mit runden Unschärferingen. Ein gutes Bokeh erziele ich hingegen mit meinen Canon-Objektiven 55/1.2 und 85/1.8.
Das Bild ist in einem wesentlichen Teil des Motivs scharf, während unscharfe Bereiche subjektiv die Gesamtbildwahrnehmung unterstreichen.

Sound-Bokeh ist die subjektive Wahrnehmung des Gesamtklangs in einem bestimmten Kontext.
Direkter Schall lässt sich gewissermaßen mit dem scharf fokussierten Bereich eines Bildes vergleichen. Die Wahrnehmung von direktem Schall erhält durch Reflexionen eine zusätzliche Dimension. Direkter Schall allein, ohne Reflexionen, erzeugt in der Regel keinen guten Klang.
Der Bokeh-Effekt des Klangs variiert in verschiedenen Räumen je nach Mischung aus Direktschall und Reflexionen.
Schlechter Bokeh-Effekt entsteht in einer langen, engen Höhle, in der die Reflexionen mehr als 12 dB stärker sind als der Direktschall. Jegliche Sprache wird von den Reflexionen vollständig überlagert und ist unverständlich.
In normalen Hörräumen ist das Bokeh meist nur mäßig gut. Die Reflexionen heben den Direktschall nicht optimal hervor.
Die optimale Wahrnehmung eines Bokeh-Effekts ist subjektiv und oft ein Anpassungsprozess, der Kompromisse mit sich bringt. Dieser Anpassungsprozess verliert mit der Zeit oft an Wirkung, und die Suche nach einem besseren Bokeh beeinflusst häufig die Leidenschaft von HiFi-Enthusiasten.

Das optimale Bokeh hängt stark von den Eigenschaften der Schallquelle und des Raumes sowie von Ihren eigenen subjektiven Vorlieben ab.

Ich persönlich habe im Laufe der Jahre unterschiedliche optimale Bokeh-Effekte erlebt.
Anfangs war meine erste Stereoanlage eine enorme Verbesserung, ein gewaltiger Bokeh-Effekt, verglichen mit dem Transistorradio meiner Familie.
Dann folgten weitere Verbesserungen des Bokeh-Effekts durch Hornlautsprecher und die Möglichkeit hoher Lautstärken. Schallpegel über 85 dB kaschieren messbare Verzerrungen und führen zu subjektiv geringeren Verzerrungen.
Die Röhrenverstärker verliehen dem Klang mehr Bokeh und sorgten für einen weicheren Klang. Verzerrungen zweiter und dritter Ordnung wurden kaschiert.
EQ sorgte für ein noch besseres Bokeh mit besserem Bass unterhalb von 300 Hz in der Hörposition und einer linearen Frequenzkurve oberhalb von 300 Hz im Freifeld.
Dipole ermöglichten durch optimalere Reflexionen weitere Verbesserungen des Bokeh-Effekts im räumlichen Erlebnis.
Ein neu gebautes großes Haus mit optimierten Reflexionen, bei denen die seitlichen Reflexionen dominant waren (um etwa 8 dB gedämpft, um etwa 17 ms verzögert und mit ähnlicher Frequenzkurve wie der Direktschall). Andere Reflexionen sollten um etwa 30 dB gedämpft sein. (Barron, Toole, Olive, Lokki)
Die Eigenschaften des wiedergegebenen Klangs sind ebenfalls entscheidend. Sprache und komplexe Musik erzeugen in einem bestimmten System und Raum oft ein anderes, gutes Bokeh.

Objektive Messdaten korrelieren oft, aber nicht immer, mit einem guten Bokeh-Effekt.
Mit der richtigen Auswahl an Messdaten kann die Physik den wahrgenommenen Bokeh-Effekt verbessern.

Seien Sie vorsichtig und stolz auf Ihr eigenes subjektives Bokeh im jeweiligen Raum.

Neuro

I might be able to contribute something interesting here, essentially an analogy to HiFi blind tests and bias.

A few years ago, at a photography event, we held a competition for the best lens bokeh. Comparable "bokeh" images were taken with over 70 lenses, including absolute favorites for bokeh and a special bokeh lens.
Afterwards, the bokeh effects could be evaluated in a direct comparison.
I don't need to emphasize here that for experts, editors, and photographers, it was already clear beforehand which was the best, or even the best, bokeh lens.
The evaluation was, of course, done blindly in a direct knockout comparison, meaning no one knew which image they were evaluating and comparing.
The results were surprisingly consistent, and the outliers were so small that they couldn't even be expressed as a percentage.

And when we published our results, there was a huge outcry, especially from specialist editors and experts, because the special bokeh lens not only landed in 12th place, but also three places behind the same lens, which wasn't specifically designed for bokeh.
Other bokeh favorites also landed in the middle of the pack, and one even came in last.

Back then, we had to listen to various accusations, ranging from that we had switched the images to accusations of fraud.
Only when we essentially forced the biggest skeptics to conduct the test themselves and publish the results were the findings accepted, as they didn't deviate from the overall results at all. Many of the myths surrounding the topic of bokeh in lenses could not be confirmed.

Does this sound familiar to anyone?

 

[pablolie]

So is your starting point, listening in an anechoic space?

It's pretty much nobody's. And I am not sure I follow the analogy. Light reflections aren't lens bookeh. We're extending this metaphor to a bizarre extent.

 

[dlaloum]

It's pretty much nobody's. And I am not sure I follow the analogy. Light reflections aren't lens bookeh. We're extending this metaphor to a bizarre extent.

I beg to differ - watch a screen in a brightly lit room, then watch it in the dark... big difference!

Or for a closer analogy, a bright screen in a white walled room, vs the same screen in a room painted black or with black curtains - seems to me the metaphore is quite fitting!

 

[Chr1]

Another couple of pages and I'll be beginning to miss car anologies

 

[ahofer]

Well, I assume we/you need our/your own intensive subjective assessment through actual experiments, in our/your own acoustic environments.

Otherwise, we will be easily trapped by endless and downward discussion spirals, whatever "term", blur or bokeh or diffusion or dispersion, we would use. I mean there can be no rational objective "generalization" discussion on our present topic.

Let me suggest you just one "extreme" example case of audio experiment.

If you have (or you can affordably introduce) highly efficient metal horn super-tweeter to cover ca. 8 kHz to 25 kHz singing together with your tweeter, I would recommend you trying wide-3D reflective dispersion of the super-tweeter sound by using hard-random-surface material in various relative gains against tweeter, as well as in various physical positioning settings, like I have done it.

Spoiler

- A new series of audio experiments on reflective wide-3D dispersion of super-tweeter sound using random-surface hard-heavy material:
Part-1_ Background, experimental settings, initial preliminary listening tests: #912
Part-2_ Comparison of catalogue specifications of metal horn super-tweeter (ST) FOSTEX T925A and YAMAHA Beryllium dome tweeter (TW) JA-0513; start of intensive listening sessions with wide-3D reflective dispersion of ST sound: #921
Part-3_ Listening evaluation of sound stage (sound image) using excellent-recording-quality lute duet tracks: #926
Part-3.1_ Listening evaluation of sound stage (sound image) using excellent-recording-quality jazz trio album: #927
Part-4_Provisional conclusion to use Case-2 reverse reflective dispersion setting in default daily music listening: #929

I believe that you yourself will subjectively find/hear various sound perspectives through this simple actual experiments in your present room acoustic environments; some of the sound perspectives would be completely unacceptable for you, some would give almost no change, and some would give excellent improvements, the determination/decision is totally up to your listening preference, whatever "term", blur or bokeh or diffusion or dispersion, you would use for rationalization of your subjective results (pros or cons).

You may share "your" experimental settings and subjective results with other people (again I have done it), but it would never to be the objective generalization for all the people, since we always have different acoustic environments.

There’s tension between this view and a widely accepted view here that Toole and Olive’s experiments showed some significant central tendency towards particular dispersion patterns. T&O is underpowered, of course, but it has proven to be a good guide in my case.

 

[rf1938]

There’s tension between this view and a widely accepted view here that Toole and Olive’s experiments showed some significant central tendency towards particular dispersion patterns. T&O is underpowered, of course, but it has proven to be a good guide in my case.

As a professional cinematographer for over 50 years, I'd like to clarify the term "bokeh." In the film world, bokeh doesn't just refer to the fact that items further away from a telephoto, or "long" lens are out of focus - bokeh rather refers to the character of those out of focus parts of the frame. That character is partly impacted by the number of blades in the aperture iris, and also the design of the lens. An interesting take on this in the context of audio discussion is that modern highly accurate aspherical lenses produce such uninteresting bokeh that there is now a significant market for vintage lenses, say 50 years old, in which the bokeh cinematographers are looking for is technically a distortion caused by spherical lens design. older lenses produce far more character and are more desirable than the more perfect current designs - and for ASR readers, this artifact is most definitely measurable. Whether you like it or not is in the eye of the viewer -

 

[pablolie]

I beg to differ - watch a screen in a brightly lit room, then watch it in the dark... big difference!

Or for a closer analogy, a bright screen in a white walled room, vs the same screen in a room painted black or with black curtains - seems to me the metaphore is quite fitting!

"A closer analogy"? I think not. Why not throw in a flashing disco ball while you're at it so it has even remotely anything to do with music? :-D

Bokeh is an entirely personal preference when it comes to putting a subject in focus and blurring other stuff. Its merit isn't EVER "measureable". It's kind of the total opposite in music reproduction. We want the sharpest f-stop - period. We want everything sharp in ASR, and we want to *measure* the focus... unless you venture into personal preferences like vinyl and compact cassettes and warm tubes etc etc. All good if that's one's preference, but the "metaphor" goes even contrary to silly audio platitudes like "a complete dark, black background" (meaning zero background noise, whereas bokeh is all about *creating* background noise) and such; since this is advocating coloration and blurriness. Sorry.

If you gents want to claim *every* audio system is inevitably flawed because of room effects and whatever, fine and glad you personally enjoy living with it, but bokeh is *not* a valid analogy, because it is something most of us in here do not see as a creative virtue in audio systems. We want the original. Not a blurred copy thereof. I want to hear every instrument in the band, not just the vocalist or solo instrument (with everything else mashed into indistinct background noise).

 

[ahofer]

"A closer analogy"? I think not. Why not throw in a flashing disco ball while you're at it so it has even remotely anything to do with music? :-D

Bokeh is an entirely personal preference when it comes to putting a subject in focus and blurring other stuff. It's merit isn't EVER "measureable". It's kind of the total opposite in music reproduction. We want the sharpest f-stop - period. We want everything sharp in ASR, and we want to *measure* the focus... unless you venture into personal preferences like vinyl and compact cassettes and warm tubes etc etc. All good if that's one's preference, but the "metaphor" goes even contrary to silly audio platitudes like "a complete dark, black background" (meaning zero background noise, whereas bokeh is all about *creating* background noise) and such; since this is advocating coloration and blurriness. Sorry.

If you gents want to claim *every* audio system is inevitably flawed because of room effects and whatever, fine and glad you personally enjoy living with it, but bokeh is *not* a valid analogy, because it is something most of us in here do not see as a creative virtue in audio systems. We want the original. Not a blurred copy thereof. I want to hear every instrument in the band, not just the vocalist or solo instrument (with everything else mashed into indistinct background noise).

Yes, we seem to be talking about a)inaccuracies or shortcomings of equipment, b) room obstacles to fidelity, or c)production choices.

 

[pablolie]

Yes, we seem to be talking about a)inaccuracies or shortcomings of equipment, b) room obstacles to fidelity, or c)production choices.

Indeed, thanks for the follow up.

I'll provide an example of bokeh:

I took this with a 50mm lens at ~f1.8.

The focus is on the beauty of the main subject. Everything else... bar details in the background... doesn't matter. Creative focus. I just want to see and remember her (she is gone, sadly... a big love in my life, and when I look at the pic it is more powerful for the lack of background distraction, and allows me to shed a tear because it is *just* her... I could not care less about which beer the bar had on tap).

But I would *never* want that effect with music. I'd never want to hear just Daniel Hope's violin solo while the rest of the orchestra is mashed into indistinct background noise. I want the first and second violins and violas and cellos and the piano clearly placed and immaculately reproduced to complete the picture of the performance. No blurring, thank you. I don't care how bad the room is, none of it would ever completely disappear into bokeh.

 

[ahofer]

 

[RexrothPigeon]

An interesting take on this in the context of audio discussion is that modern highly accurate aspherical lenses produce such uninteresting bokeh that there is now a significant market for vintage lenses, say 50 years old, in which the bokeh cinematographers are looking for is technically a distortion caused by spherical lens design. older lenses produce far more character and are more desirable than the more perfect current designs - and for ASR readers, this artifact is most definitely measurable. Whether you like it or not is in the eye of the viewer -

Yes, artists in all media take whatever liberties they like to create beauty. Many recording engineers use vintage gear. Many musicians use vintage gear.

This has nothing to do with listeners at home--applying distortion at the listening stage of the whole chain would be closer to, say, buying a photo, then smearing vaseline over parts of it to make them blurrier.

 

[Keith_W]

As a professional cinematographer for over 50 years, I'd like to clarify the term "bokeh." In the film world, bokeh doesn't just refer to the fact that items further away from a telephoto, or "long" lens are out of focus - bokeh rather refers to the character of those out of focus parts of the frame. That character is partly impacted by the number of blades in the aperture iris, and also the design of the lens. An interesting take on this in the context of audio discussion is that modern highly accurate aspherical lenses produce such uninteresting bokeh that there is now a significant market for vintage lenses, say 50 years old, in which the bokeh cinematographers are looking for is technically a distortion caused by spherical lens design. older lenses produce far more character and are more desirable than the more perfect current designs - and for ASR readers, this artifact is most definitely measurable. Whether you like it or not is in the eye of the viewer -

You make an excellent point. Old Leica lenses sell for serious money, particularly the ones that have a lot of "character". So much so that Leica realized there's a gold mine and they have started releasing modern versions of old lenses. Exhibit 1: Leica Thambar 90mm f/2.2.

 

[dualazmak]

OK, let me join again sharing only one of my photos which I referred in my post #6 where it was/is under the spoiler cover.
In this post, I share it not under spoiler cover for your direct observation.

In July last year, I posted one typical photo with beautiful (and rather intensive) "bokeh" background taken by CANON EF24-105mm F4L IS II USM lens attached to CANON EOS 5D Mark IV DSLR camera (ref. my post here and here). Please simply PM me if you would like to have original jpeg photo of 6517x4381, FL 85 mm, f/4 (open aperture), 1/1250 sec, ISO 640, 11.4 MB, no-flash, hand-held.

Maybe, the bokeh in this photo would be "uninteresting" according to the feelings of @rf1938, @pablolie and @Keith_W, though...