Properties of speakers that creates a large and precise soundstage

[audiofooled]

I've shared this before, but it doesn't hurt to do it again because Geddes provides some very good and intuitive explanations on speaker radiation pattern and room interaction, also how do we perceive it in terms of how our hearing works and at what frequencies, reflections included:

 

[jim1274]

I've shared this before, but it doesn't hurt to do it again because Geddes provides some very good and intuitive explanations on speaker radiation pattern and room interaction, also how do we perceive it in terms of how our hearing works and at what frequencies, reflections included:

Interesting stuff, but focused on unipolar forward firing “box” speakers. The part where he analyzed the dipole didn’t yield useful results, unless I did not understand correctly.

 

[jim1274]

I read through the 38 new posts since this post almost 2 weeks ago. Just thought I would weigh in after finally doing an instantaneous A/B for my Duevel Omnis vs “box” speaker. It’s really hard to compare without switching back and forth in real time. The difference in sound stage is pronounced when compared directly. When switching from Omni to box, the soundstage collapses by comparison, most notable in depth and also in height. The performers seem to occupy a much larger area with the Omnis. The box speakers never seem to completely disappear like the Omnis do, becoming more pronounced quickly as one moves off the dead center sweet spot. The increase in reflections from behind and to the side of the Omnis has a whole different character than the reduced reflected sound from a forward firing box speaker has an entirely different character, in a good way IMHO. The only other set of ears available is the wife, so I said nothing and just asked for impression and comment after
going back and forth on a few songs she knows well. She said the the Omnis sounded more like a real band in the room or some
Such and added that they sounded very different.

Since the thread title is “large and precise soundstage”, I’m thinking dipole may be a strong contender that excels in the combination of the two. I just swapped my box speakers out and put dipoles in to A/B against the Omnis, and they approach the Omnis in size of soundstage, but rival “box” in the spatial positioning precision. I Put a summary of my initial impressions in post 288 here:

Omnidirectional speakers

I just posted this in the “Dipole vs box speakers” thread, so figured I should add here in the Omni thread too: Ok—here is my first in room response curve sweep for the Enterprise Omnis. I used the mic in my iPhone for the test. I took the measurement from the centered listening position...

audiosciencereview.com

 

[audiofooled]

Interesting stuff, but focused on unipolar forward firing “box” speakers. The part where he analyzed the dipole didn’t yield useful results, unless I did not understand correctly.

Yes, he focuses on forward firing speakers and how they perform in a room based upon the DI, which is the ratio of sound power, (the average of radiated power in all directions), and direct sound at particular frequency. He says that DI should be flat and above 6dB ranging from 700-7000Hz, based upon research on gammatone filters impulse response and time that the auditory system takes to process the sound.

The idea is that if the frequency response is flat along an axis other than 0 degrees, and provided that the DI and FR is flat along that axis and before mentioned frequency range, one would be able to toe the speakers in as to avoid the early lateral reflections up to a point that we actually process the direct sound before the reverberant field would affect the imaging. He says in small rooms this is very hard to do and I agree. But he shows the advantage of his design and that by using either toe in or bringing the speakers closer together you can get a very wide sweet spot where you would have good imaging, also neutral/natural sound.

The point is that if the loudspeaker is designed to be flat only at 0 degrees, you can't toe them in because in most cases the off axis response would be other than flat regarding DI within the critical frequency range. One would argue that we actually don't need flat DI, but at least smooth, which is also rarely the case and manufacturers usually do not publish the polar response data. If this is the case, then we actually know nothing about how the loudspeaker would perform in a room.

About the dipole speaker, he says his software isn't designed for it because it needs a DI calibration and dipoles radiate differently, but the loudspeaker he chose doesn't have much of a uniform polar response so it is safe to assume that the reverberant field would not have similar tonality as the direct sound. In room this means it would actually not be "room friendly", so to speak. As far as imaging, it would be placement and listening position sensitive. Perhaps it would have a wider sound stage because of the lack of directivity, but good imaging requires more of the direct sound.

It's always about trade-offs, but I like his approach, it makes sense to me and it has been my experience that sound stage width isn't something I want at any cost, but it's a property of the recording itself. There are recordings that are wide and others less so but equally enjoyable if the system is able to provide good imaging of what's in the recording itself. Radiation pattern control is a part of the solution IMO.

 

[jim1274]

Yes, he focuses on forward firing speakers and how they perform in a room based upon the DI, which is the ratio of sound power, (the average of radiated power in all directions), and direct sound at particular frequency. He says that DI should be flat and above 6dB ranging from 700-7000Hz, based upon research on gammatone filters impulse response and time that the auditory system takes to process the sound.

The idea is that if the frequency response is flat along an axis other than 0 degrees, and provided that the DI and FR is flat along that axis and before mentioned frequency range, one would be able to toe the speakers in as to avoid the early lateral reflections up to a point that we actually process the direct sound before the reverberant field would affect the imaging. He says in small rooms this is very hard to do and I agree. But he shows the advantage of his design and that by using either toe in or bringing the speakers closer together you can get a very wide sweet spot where you would have good imaging, also neutral/natural sound.

The “neutral/natural” sound is a key point—what good is huge immersive soundstage if music has coloration and other sonic flaws? Early reflections create more challenges with a multi-polar radiation—unipolar forward firing speakers are more tolerant to closer spacing to the front wall. With the Omni and dipole radiation pattern, you need to move well into the room to account for early reflections from the front wall. I’ve done more placement location testing with the Omnis and dipoles in an attempt to get the right balance of direct to reflected sound, both in speaker placement from front wall and adjusting listening position closer and further from the speakers. It all is a balancing act, finding that moving the Omnis much further from the front wall and closer to my normal listening position (the couch) to increase direct sound, the then closer proximity to rear wall notably changed the sound. By shortening the reflective sound time from the rear wall behind me, the sound appeared to be coming from the side and rear more—sounded like sound was coming from my side surrounds on my 7.4.1 ATMOS rig when playing a multichannel recording. I suspect a forward firing box speaker might have some of same effect when placed well into the room, but without the “balancing” effect of front wall reflections of an Omni or dipole. Before this experiment is over, I plan to set up a grid to try various front to rear positions of all 3 speaker radiation types and note the differences. I did that a bit with blue tape on the floor for the Omni location testing, but my cat pulled the tape up faster than I could put it down—maybe trick her with chalk lines instead.

The point is that if the loudspeaker is designed to be flat only at 0 degrees, you can't toe them in because in most cases the off axis response would be other than flat regarding DI within the critical frequency range. One would argue that we actually don't need flat DI, but at least smooth, which is also rarely the case and manufacturers usually do not publish the polar response data. If this is the case, then we actually know nothing about how the loudspeaker would perform in a room.

That is where the Omni excels—the 360 degree radiation pattern presents a very similar sound at any listening position. With a forward firing box speaker the sound changes significantly as you move away from the “sweet spot”. That may not matter if one is primarily listening from only one location. I did some Omni in room frequency response tests at various locations, even in another room. When measuring from the opening from living room well into the kitchen at the furthest position where I could still just see the Omnis, the response was still somewhat similar to the central sweet spot position in the living room—think I posted some graphs over in the Omni thread. When I rotate the box speakers back in, I’ll try the same experiment, but have a pretty good idea what results will be.

About the dipole speaker, he says his software isn't designed for it because it needs a DI calibration and dipoles radiate differently, but the loudspeaker he chose doesn't have much of a uniform polar response so it is safe to assume that the reverberant field would not have similar tonality as the direct sound. In room this means it would actually not be "room friendly", so to speak. As far as imaging, it would be placement and listening position sensitive. Perhaps it would have a wider sound stage because of the lack of directivity, but good imaging requires more of the direct sound.

I’m not sure if I agree with that if understood correctly. At any listening position much removed from the sweet spot, an Omni (and to lesser extent dipole) is as room friendly as it gets.

The point about tonality is well taken. That said, I’ve not seen a big tonality penalty on the Omni, but am looking closer at that now. My initial focus was more on soundstage envelopment, immersion, spaciousness or whatever term you prefer. Even if a box speaker at the sweet spot has better tonality at the sweet spot, that is negatively impacted as one moves further off axis of the central position.

It's always about trade-offs, but I like his approach, it makes sense to me and it has been my experience that sound stage width isn't something I want at any cost, but it's a property of the recording itself. There are recordings that are wide and others less so but equally enjoyable if the system is able to provide good imaging of what's in the recording itself. Radiation pattern control is a part of the solution IMO.

No question there is a soundstage component of the recording, but room and speaker location/radiation pattern are critical too. The soundstage aspect of the original mastering impact the resultant in room soundstage characteristics—wider recording mixes come through wider on both unipolar and multi-polar designs. The one type of recording that I found the Omnis (and dipole to an extent) are ones with a lot of reverb in the original.

 

[audiofooled]

I’m not sure if I agree with that if understood correctly. At any listening position much removed from the sweet spot, an Omni (and to lesser extent dipole) is as room friendly as it gets.

The point about tonality is well taken. That said, I’ve not seen a big tonality penalty on the Omni, but am looking closer at that now. My initial focus was more on soundstage envelopment, immersion, spaciousness or whatever term you prefer. Even if a box speaker at the sweet spot has better tonality at the sweet spot, that is negatively impacted as one moves further off axis of the central position.

It's all about balancing the energy, time of arrival and phase of the direct sound and reflections. With listening distance you also balance the direct/reverberant field in room. With wider/less directivity, the ratio of direct/reflected sound is such that you give more energy to lateral reflections. Sound stage would be wider but the imaging would be blurred and lose definition because early reflections are naturally the means of telling where the sound source is located. If the radiation pattern is wide but uniform you still have a chance of having neutral tonality but also lose imaging precision.

With controlled directivity and beam width, you get image precision, more sound stage depth, but sound stage width is dictated by how wide the actual recording is.

It's actually more complex than this, perhaps this presentation of Beolab 90, which has controlled beam width, can put things into perspective:

 

[Westsounds]

It's all about balancing the energy, time of arrival and phase of the direct sound and reflections. With listening distance you also balance the direct/reverberant field in room. With wider/less directivity, the ratio of direct/reflected sound is such that you give more energy to lateral reflections. Sound stage would be wider but the imaging would be blurred and lose definition because early reflections are naturally the means of telling where the sound source is located. If the radiation pattern is wide but uniform you still have a chance of having neutral tonality but also lose imaging precision.

With controlled directivity and beam width, you get image precision, more sound stage depth, but sound stage width is dictated by how wide the actual recording is.

It's actually more complex than this, perhaps this presentation of Beolab 90, which has controlled beam width, can put things into perspective:

It’s still an illusion, no matter how you package it, or for that matter put as many DSP’s and amps on it as B&O have done here. Not forgetting the exorbitant price tag they add to it to sell you these speakers.


That was an interesting video to watch actually, all propaganda of course and marketing BS in order for you to think their speakers do something magically that others don’t. Well they don’t, you could do it yourself for a very small fraction of the cost B&O are charging. Plus, their speakers are very ugly!

 

[Purité Audio]

The 90’s do, do something other speakers can’t variable directivity, they are really interesting if you have the chance listen to a pair and switch between ‘narrow’ and ‘wide’ modes.
Keith

 

[Westsounds]

The 90’s do, do something other speakers can’t variable directivity, they are really interesting if you have the chance listen to a pair and switch between ‘narrow’ and ‘wide’ modes.
Keith

Yes, ok they have multiple drivers that fire in different directions. This is something that has been done before, it’s not new. Plus DSP’s are not new, any ‘competent’ DIY’er could do something similar with multiple amps and DSPs and still not get anywhere near their price tag.

It is a complete all in one solution, I’m not disputing that. But they still look absolutely terrible, subjectively speaking of course

If you want a much cheaper fancy DSP with sound in all directions and sound coming from all nocks and crannies, some sound bars do it as impressively these days, such as Samsungs Q990C. Ok it’s not got the build, drive units or amplifiers to match the B&O, but it’s probably equally impressive under the right settings and capable of playing more audio formats and standards. But it’s also 0.00125% of the price

 

[goat76]

Not exactly related to the properties of speakers, but more about the properties of recordings that have natural-sounding soundstage...

I think John Cuniberti's OneMic series of recordings are great examples of how convincing the soundstage can be when everything is recorded from a single point in space with only one single stereo microphone. All the sound sources and the position of the singer are throughout and staged to give a convincing soundstage, and what comes with the package is that all the sounds from the recorded space, both direct sounds from the sound sources and the reflective sounds from the venue, meet up perfectly and natural at one single point in space where the microphone is placed, which almost resembles what a single listener would hear standing there (except that band now sounds as if they all where standing in front of listener).

 

[youngho]

I think John Cuniberti's OneMic series of recordings are great examples of how convincing the soundstage can be when everything is recorded from a single point in space with only one single stereo microphone. All the sound sources and the position of the singer are throughout and staged to give a convincing soundstage, and what comes with the package is that all the sounds from the recorded space, both direct sounds from the sound sources and the reflective sounds from the venue, meet up perfectly and natural at one single point in space where the microphone is placed, which almost resembles what a single listener would hear standing there (except that band now sounds as if they all where standing in front of listener).

The description of the microphone technique at https://tapeop.com/interviews/144/john-cuniberti/ reminded me of the Blumlein microphone technique, and indeed, the AEA R88 (https://aearibbonmics.com/products/r88-series/) is configured thusly. You can find more recordings at https://aearibbonmics.com/onemic/. Robert E Greene argues that such recordings are most accurately produced with speakers separated to 90 degree angle, if I'm paraphrasing him correctly.

 

[goat76]

The description of the microphone technique at https://tapeop.com/interviews/144/john-cuniberti/ reminded me of the Blumlein microphone technique, and indeed, the AEA R88 (https://aearibbonmics.com/products/r88-series/) is configured thusly. You can find more recordings at https://aearibbonmics.com/onemic/. Robert E Greene argues that such recordings are most accurately produced with speakers separated to 90 degree angle, if I'm paraphrasing him correctly.

Yes, I'm aware of the microphone used and the recording technique, and I think I have seen all the available videos of the OneMic Series recordings.

I think it's very cool, it sounds so natural when everything is recorded from one single point in space, as both the direct sounds from the sound sources and the reflected sounds from the environment end up coming in correctly to that point in space. The same natural thing can simply never occur with multiple microphones spaced out in the recording space.

It's a lot of preparation to get it to work though. Finding the perfect positions of all the instruments and amps to get the natural panning right, using the microphones on-axis and nulls cleverly both to enhance and avoid different things and setting levels and distances to get a well-balanced mix from the get-go. It can't be an easy task, but once it is all set it's just a good performance from the artists, and the record is almost finished.

 

[youngho]

Yes, I'm aware of the microphone used and the recording technique, and I think I have seen all the available videos of the OneMic Series recordings.

I think it's very cool, it sounds so natural when everything is recorded from one single point in space, as both the direct sounds from the sound sources and the reflected sounds from the environment end up coming in correctly to that point in space. The same natural thing can simply never occur with multiple microphones spaced out in the recording space.

It's a lot of preparation to get it to work though. Finding the perfect positions of all the instruments and amps to get the natural panning right, using the microphones on-axis and nulls cleverly both to enhance and avoid different things and setting levels and distances to get a well-balanced mix from the get-go. It can't be an easy task, but once it is all set it's just a good performance from the artists, and the record is almost finished.

Thanks for posting this! I wasn't aware that about these recordings or microphone, so I included the links for myself and other folks' reference. I did enjoy reading about the history behind another non-classical Blumlein technique recording: https://www.soundonsound.com/techniques/classic-tracks-cowboy-junkies-sweet-jane

 

[Axo1989]

Yes, ok they have multiple drivers that fire in different directions. This is something that has been done before, it’s not new. Plus DSP’s are not new, any ‘competent’ DIY’er could do something similar with multiple amps and DSPs and still not get anywhere near their price tag.

It is a complete all in one solution, I’m not disputing that. But they still look absolutely terrible, subjectively speaking of course

You think B&O loudspeakers are ugly? No, abusing apostrophes to make plurals out of acronyms is ugly.

If you want a much cheaper fancy DSP with sound in all directions and sound coming from all nocks and crannies, some sound bars do it as impressively these days, such as Samsungs Q990C. Ok it’s not got the build, drive units or amplifiers to match the B&O, but it’s probably equally impressive under the right settings and capable of playing more audio formats and standards. But it’s also 0.00125% of the price

Being more serious now, it's fair to say that they are high-priced speakers, of course. But as @Purité Audio has said, you oversimplify the application of technology in this case, as well as side-stepping that full-range high SPL in larger rooms requires speakers of scale—independent of the technical/design approach—and that always increases cost.

 

[jim1274]

It's all about balancing the energy, time of arrival and phase of the direct sound and reflections. With listening distance you also balance the direct/reverberant field in room. With wider/less directivity, the ratio of direct/reflected sound is such that you give more energy to lateral reflections. Sound stage would be wider but the imaging would be blurred and lose definition because early reflections are naturally the means of telling where the sound source is located. If the radiation pattern is wide but uniform you still have a chance of having neutral tonality but also lose imaging precision.

Understood that imaging precision has been a trade-off of soundstage size and “immersive” aspect in my comparisons. I suppose it comes down to ones personal preference of the trade-offs? I personally have found, at least at these early stages of my “soundstage” experiments, that the additive soundstage effect of the additional reflections from multi-polar radiation outweigh the loss of imaging precision. Balancing direct/reflective as you noted is absolutely key and a critical component on speakers that have Omni or dipole radiation patterns. If the multipolar dispersion speaker position is not dialed in, the sound suffers greatly—forward firing unipolar seems to be more forgiving as long as early side reflections are considered and adressed.

Neutral tonality is important too, but at least so far, I have not found notable anomalies as long as the Omnis and dipoles are located properly within the room. I’ve focused more on soundstage aspects so far, so that comment is only early observations subject to more A/B testing.

With controlled directivity and beam width, you get image precision, more sound stage depth, but sound stage width is dictated by how wide the actual recording is.

It's actually more complex than this, perhaps this presentation of Beolab 90, which has controlled beam width, can put things into perspective:

Yeah, I second the “more complex” statement for sure. I’ve read and watched presentations found on the forum and suggested by others in the threads I’ve posted to, ones by Toole, Griesinger, Gedees, and such. I’m still somewhat of a neophyte on the science end of this, but learning—you far more experienced folks have a leg up on that part. I have owned and listened to many speakers over 5 decades, so at least have some experience on the more pragmatic and subjective aspects of evaluation and comparisons. And thanks to all for not hammering me too hard when I stray outside the lanes..

 

[jim1274]

Not exactly related to the properties of speakers, but more about the properties of recordings that have natural-sounding soundstage...

I think John Cuniberti's OneMic series of recordings are great examples of how convincing the soundstage can be when everything is recorded from a single point in space with only one single stereo microphone. All the sound sources and the position of the singer are throughout and staged to give a convincing soundstage, and what comes with the package is that all the sounds from the recorded space, both direct sounds from the sound sources and the reflective sounds from the venue, meet up perfectly and natural at one single point in space where the microphone is placed, which almost resembles what a single listener would hear standing there (except that band now sounds as if they all where standing in front of listener).

This sounds like a good track to run through the monopole/dipole/omni comparison for soundstage aspects.

I found the track on Tidal and Qobuz from the “Desert Pavement” album, but not the “one mic series”—is the YouTube link the only option?

 

[jim1274]

The description of the microphone technique at https://tapeop.com/interviews/144/john-cuniberti/ reminded me of the Blumlein microphone technique, and indeed, the AEA R88 (https://aearibbonmics.com/products/r88-series/) is configured thusly. You can find more recordings at https://aearibbonmics.com/onemic/. Robert E Greene argues that such recordings are most accurately produced with speakers separated to 90 degree angle, if I'm paraphrasing him correctly.

Thanks for the links—another rabbit hole to dive into….

Made me think of Mapleshade Recordings a bit:

“Our recording are all recorded live to 2-track analog tape with no EQ, no overdubs, no filtering, no compression, or other studio cosmetics. The result is similar to that warm Sun Studio or Blue Note sound of the ’50s but even clearer and more live, blurring the barrier between the recording studio and the performance stage”

Not the same thing, obviously, and nothing new—Sheffield “direct to disc” from back in the day was similar.

Just noted as it is similar in the “minimalist” recording approach if I understood correctly.

I suspect everyone here knows “Jazz at the Pawnshop”, another classic live recording that could probably also be considered “minimalist”, a top candidate for “natural” sounding live capture.

The recording of "Jazz at the Pawnshop"

I hope this interesting description of the recording of "Jazz at the Pawnshop" has not been posted here before... JAZZ AT THE PAWNSHOP - An Audiophile Classics When recording engineer Gert Palmcrantz was loading his car with equipment outside Europa Film Studios on December 6th, 1976, it was only...

audiophilestyle.com

 

[youngho]

Understood that imaging precision has been a trade-off of soundstage size and “immersive” aspect in my comparisons. I suppose it comes down to ones personal preference of the trade-offs? I personally have found, at least at these early stages of my “soundstage” experiments, that the additive soundstage effect of the additional reflections from multi-polar radiation outweigh the loss of imaging precision. Balancing direct/reflective as you noted is absolutely key and a critical component on speakers that have Omni or dipole radiation patterns. If the multipolar dispersion speaker position is not dialed in, the sound suffers greatly—forward firing unipolar seems to be more forgiving as long as early side reflections are considered and adressed.

I wonder if this is quite a bit more complex than a simple tradeoff between "sharp imaging" (my words) or "definition" versus wide soundstage (increased ASW) and listener envelopment (LEV). Perhaps there are aspects of:

Auditory envelopment (AE) related to ITD at low frequencies @Thomas Lund ): https://www.audiosciencereview.com/...bass-and-subwoofers.51589/page-4#post-1871225

Envelopment from 50-700 Hz (@Thomas Lund ): https://www.genelec.com/-/blog/how-to-analyse-frequency-and-temporal-responses

"Frequencies below 500Hz are primarily responsible for perceptions of Resonance, Envelopment, Warmth”: http://www.davidgriesinger.com/ICA_2004 imbedded.pptx

"The special role of 500 Hz in binaural neural processing may not be entirely fortuitous. Because of the size of the human head, this frequency range corresponds to a minimum in coherence when the soundfield is isotropic": https://web.pa.msu.edu/acoustics/koller.pdf

700 Hz middle ear high pass filter (@j_j ): https://www.aes-media.org/sections/pnw/ppt/jj/aes_apr2019_hearing099.pptx, possible implications at https://www.audiosciencereview.com/...matter-in-audio-no.24026/page-30#post-1871687, more at https://www.audiosciencereview.com/forum/index.php?threads/our-perception-of-audio.501/page-17

Localization from ITD/phase lock from bass frequencies up to about 1 kHz (@j_j ): https://www.audiosciencereview.com/...matter-in-audio-no.24026/page-30#post-1874667

With two ears, ITD is comparison of time relationships between waveform < 500 Hz, mix of waveform and envelope 500 Hz to 2 kHz, envelope leading edge >2 kHz. Leading edges in ERB emphasized relative to steady state due to onset of compression (part of Haas effect). ILD communicated to brain (@j_j ): https://www.aes-media.org/sections/pnw/ppt/jj/auditory_mechanisms_01_28_21.pptx

“Frequencies above 1kHz are primarily responsible for perceptions of Timbre, Clarity, Intelligibility, Distance”: http://www.davidgriesinger.com/ICA_2004 imbedded.pptx

Transition from phase sensitivity to envelope onset around 1 kHz to 4 kHz (@j_j ): https://www.audiosciencereview.com/...matter-in-audio-no.24026/page-30#post-1874667

"As the frequency of a sound increases beyond 1000 Hz, there is a substantial degradation in the ability of the binaural system to make use of ITD in the waveform. Timing in the fine structure of a tone or noise ceases to be of value. Instead, listeners are able to make use of ITD in the envelope of sounds. If there is no structure in the envelope, as for a continuous sine tone, then listeners cannot localize. For noise, like the third-octave noises used in our experiments, the ITD in the temporal fluctuations can be used. Given the significance of envelope ITDs at mid and high frequencies, it would seem that the waveform cross correlation and waveform coherence, as measured in the experiments reported here, are less interesting than the cross-correlation and coherence of the envelope. However, the coherence of the waveform and of the envelope are statistically related": https://web.pa.msu.edu/acoustics/koller.pdf

ATF/HRST boosts ~1 kHz for waves from behind, near 3 kHz from front (Above 4 kHz, outer ears and pinnae scatter significantly, quite individual-specific above 6 kHz mostly with valley-and-peak structure that shifts with frequency, peaking near 7 kHz with source directly overhead), ILD large and reliable above 3 kHz: https://www.cogsci.msu.edu/DSS/2019-2020/Hartmann/Hartmann_1999.pdf

“The head masks sounds: this shadow effect reduces intensity, especially at higher frequencies [10]. For wavelengths shorter than head diameter, the head partially decreases acoustic energy by reflection and absorption. Thus, the lowest frequency at which the shadow effect occurs is approximately: fmin = v max = 343 0.175 ≈ 1960 Hz…ILD is thus virtually zero below 1500 Hz, and becomes relevant for wavelengths shorter than head diameter (> 1500 Hz)": https://www.sciencedirect.com/science/article/pii/S187972961830067X

“Sound stimulus frequency greatly affects the accuracy of localization [12,22,23], which is best for low frequencies (< 1000 Hz),poorest between 1000 and 3000 Hz, and intermediate for high frequencies (> 3000 Hz)…The accuracy of sound source localization thus depends on:•azimuthal position: better in front than to the side;•type of stimulus:◦ band width: the wider the band, the better the accuracy,◦ frequency: poorer between 1000 and 3000 Hz,◦ and speech or tonal type of sound": https://www.sciencedirect.com/science/article/pii/S187972961830067X

Tones have flat envelopes, so no “first arrival” information. Many reflections off small surfaces at high frequencies [>2 kHz], which interfere with each other and ITD, so hard to localize (@j_j ):" https://www.aes-media.org/sections/pnw/ppt/jj/auditory_mechanisms_01_28_21.pptx

“Comb-like filters tuned to the fundamental period of an amplitude waveform can separate the formants of a particular speaker or instrument from other signals and from noise…The alignment of phases in the upper harmonics of tones is vital to source separation and localization…Recent papers from the field of speech comprehension have come to the same conclusions about the importance of the amplitude waveform of sounds with distinct pitch. They call the process “Source separation by periodicity"" (http://www.davidgriesinger.com/Learning to Listen 14.pptx)

To me, as an uneducated layman, this suggests a number of possible implications:

What we perceive as a "large" (does that mean wide, deep, or both?) soundstage may actually be related to a number of factors, including Auditory Envelopment due to low bass reproduction to enhance perception of larger spaces (though this may be prone to distortion by the listening room), perception of envelopment due to frequencies below around 500-700 Hz, lateral reflections (possibly with a critical frequency range) as discussed by others with respect to ASW so not worth reiterating but also possibly second-image thresholds resulting in soundstage extending beyond the loudspeakers' separation), and perhaps additional effects related to listening environment (DR ratio to change perception of distance) and upper frequencies (higher frequencies muffled by air, harmonic phase alignment or envelop onset randomized by multiple reflections). The first factors listed above may related to various anecdotes about the soundstage "opening up" with subwoofers (sorry, I can't be bothered to provide examples). The latter ones may relate to the perceived effects of various diffusion products (see Ron Sauro's comments at http://nwaalabs.ipower.com/Files/NWAA Labs/Diffusion, When phase and energy becomes more important than directivity in the perception of space 2017 NOLA.pdf and https://www.stereophile.com/content/nwaa-labs-measurement-beyond-atomic-level, which I interpret as possibly resulting in the perception of more reflections having occurred, as in a larger room, plus the high frequency absorption that tends to occur with mathematical diffusion products).

What we perceive as "precise" soundstage may also be related to a number of factors, including localization as outlined above, DR ratio again, suppressing or delaying early reflections that may randomize phase or decorrelate envelope onset, but also our perception of what Griesinger calls "proximity," since he relates this to source separation and stream segregation, so if we're able to pick out and follow a specific musical "line" or "source" (whether a singer, instrument, or orchestral section). To give a different example, perhaps we're in a relatively crowded/noisy room but able to isolate a specific speaker a la the cocktail party effect. We may cognitively anchor this with visual input, i.e. seeing the speaker. With a musical recording, do we similarly anchor this ability to isolate the individual sources to which we're paying attention at one particular time with auditory localization cues? If so, perhaps different aspects of localization may be frequency and phase dependent, so maybe three ranges in order of relative importance: below 500-1000 Hz, above 2-3 (or 4?) kHz, and 0.5-1 to 2-3 khz. Add in room/modal distortion and the intrinsic first-pass filter around 700 Hz, I think there may be an interesting correlation with typical loudspeaker crossover frequency range choices.

Young-Ho

 

[Deleted member 48726]

Yes, ok they have multiple drivers that fire in different directions. This is something that has been done before, it’s not new. Plus DSP’s are not new, any ‘competent’ DIY’er could do something similar with multiple amps and DSPs and still not get anywhere near their price tag.

It is a complete all in one solution, I’m not disputing that. But they still look absolutely terrible, subjectively speaking of course

If you want a much cheaper fancy DSP with sound in all directions and sound coming from all nocks and crannies, some sound bars do it as impressively these days, such as Samsungs Q990C. Ok it’s not got the build, drive units or amplifiers to match the B&O, but it’s probably equally impressive under the right settings and capable of playing more audio formats and standards. But it’s also 0.00125% of the price

The amount of ignorance..

I wish you a happy life with your soundbar.

 

[jim1274]

I wonder if this is quite a bit more complex than a simple tradeoff between "sharp imaging" (my words) or "definition" versus wide soundstage (increased ASW) and listener envelopment (LEV). Perhaps there are aspects of:

Auditory envelopment (AE) related to ITD at low frequencies @Thomas Lund ): https://www.audiosciencereview.com/...bass-and-subwoofers.51589/page-4#post-1871225

Envelopment from 50-700 Hz (@Thomas Lund ): https://www.genelec.com/-/blog/how-to-analyse-frequency-and-temporal-responses

"Frequencies below 500Hz are primarily responsible for perceptions of Resonance, Envelopment, Warmth”: http://www.davidgriesinger.com/ICA_2004 imbedded.pptx

"The special role of 500 Hz in binaural neural processing may not be entirely fortuitous. Because of the size of the human head, this frequency range corresponds to a minimum in coherence when the soundfield is isotropic": https://web.pa.msu.edu/acoustics/koller.pdf

700 Hz middle ear high pass filter (@j_j ): https://www.aes-media.org/sections/pnw/ppt/jj/aes_apr2019_hearing099.pptx, possible implications at https://www.audiosciencereview.com/...matter-in-audio-no.24026/page-30#post-1871687, more at https://www.audiosciencereview.com/forum/index.php?threads/our-perception-of-audio.501/page-17

Localization from ITD/phase lock from bass frequencies up to about 1 kHz (@j_j ): https://www.audiosciencereview.com/...matter-in-audio-no.24026/page-30#post-1874667

With two ears, ITD is comparison of time relationships between waveform < 500 Hz, mix of waveform and envelope 500 Hz to 2 kHz, envelope leading edge >2 kHz. Leading edges in ERB emphasized relative to steady state due to onset of compression (part of Haas effect). ILD communicated to brain (@j_j ): https://www.aes-media.org/sections/pnw/ppt/jj/auditory_mechanisms_01_28_21.pptx

“Frequencies above 1kHz are primarily responsible for perceptions of Timbre, Clarity, Intelligibility, Distance”: http://www.davidgriesinger.com/ICA_2004 imbedded.pptx

Transition from phase sensitivity to envelope onset around 1 kHz to 4 kHz (@j_j ): https://www.audiosciencereview.com/...matter-in-audio-no.24026/page-30#post-1874667

"As the frequency of a sound increases beyond 1000 Hz, there is a substantial degradation in the ability of the binaural system to make use of ITD in the waveform. Timing in the fine structure of a tone or noise ceases to be of value. Instead, listeners are able to make use of ITD in the envelope of sounds. If there is no structure in the envelope, as for a continuous sine tone, then listeners cannot localize. For noise, like the third-octave noises used in our experiments, the ITD in the temporal fluctuations can be used. Given the significance of envelope ITDs at mid and high frequencies, it would seem that the waveform cross correlation and waveform coherence, as measured in the experiments reported here, are less interesting than the cross-correlation and coherence of the envelope. However, the coherence of the waveform and of the envelope are statistically related": https://web.pa.msu.edu/acoustics/koller.pdf

ATF/HRST boosts ~1 kHz for waves from behind, near 3 kHz from front (Above 4 kHz, outer ears and pinnae scatter significantly, quite individual-specific above 6 kHz mostly with valley-and-peak structure that shifts with frequency, peaking near 7 kHz with source directly overhead), ILD large and reliable above 3 kHz: https://www.cogsci.msu.edu/DSS/2019-2020/Hartmann/Hartmann_1999.pdf

“The head masks sounds: this shadow effect reduces intensity, especially at higher frequencies [10]. For wavelengths shorter than head diameter, the head partially decreases acoustic energy by reflection and absorption. Thus, the lowest frequency at which the shadow effect occurs is approximately: fmin = v max = 343 0.175 ≈ 1960 Hz…ILD is thus virtually zero below 1500 Hz, and becomes relevant for wavelengths shorter than head diameter (> 1500 Hz)": https://www.sciencedirect.com/science/article/pii/S187972961830067X

“Sound stimulus frequency greatly affects the accuracy of localization [12,22,23], which is best for low frequencies (< 1000 Hz),poorest between 1000 and 3000 Hz, and intermediate for high frequencies (> 3000 Hz)…The accuracy of sound source localization thus depends on:•azimuthal position: better in front than to the side;•type of stimulus:◦ band width: the wider the band, the better the accuracy,◦ frequency: poorer between 1000 and 3000 Hz,◦ and speech or tonal type of sound": https://www.sciencedirect.com/science/article/pii/S187972961830067X

Tones have flat envelopes, so no “first arrival” information. Many reflections off small surfaces at high frequencies [>2 kHz], which interfere with each other and ITD, so hard to localize (@j_j ):" https://www.aes-media.org/sections/pnw/ppt/jj/auditory_mechanisms_01_28_21.pptx

“Comb-like filters tuned to the fundamental period of an amplitude waveform can separate the formants of a particular speaker or instrument from other signals and from noise…The alignment of phases in the upper harmonics of tones is vital to source separation and localization…Recent papers from the field of speech comprehension have come to the same conclusions about the importance of the amplitude waveform of sounds with distinct pitch. They call the process “Source separation by periodicity"" (http://www.davidgriesinger.com/Learning to Listen 14.pptx)

To me, as an uneducated layman, this suggests a number of possible implications:

What we perceive as a "large" (does that mean wide, deep, or both?) soundstage may actually be related to a number of factors, including Auditory Envelopment due to low bass reproduction to enhance perception of larger spaces (though this may be prone to distortion by the listening room), perception of envelopment due to frequencies below around 500-700 Hz, lateral reflections (possibly with a critical frequency range) as discussed by others with respect to ASW so not worth reiterating but also possibly second-image thresholds resulting in soundstage extending beyond the loudspeakers' separation), and perhaps additional effects related to listening environment (DR ratio to change perception of distance) and upper frequencies (higher frequencies muffled by air, harmonic phase alignment or envelop onset randomized by multiple reflections). The first factors listed above may related to various anecdotes about the soundstage "opening up" with subwoofers (sorry, I can't be bothered to provide examples). The latter ones may relate to the perceived effects of various diffusion products (see Ron Sauro's comments at http://nwaalabs.ipower.com/Files/NWAA Labs/Diffusion, When phase and energy becomes more important than directivity in the perception of space 2017 NOLA.pdf and https://www.stereophile.com/content/nwaa-labs-measurement-beyond-atomic-level, which I interpret as possibly resulting in the perception of more reflections having occurred, as in a larger room, plus the high frequency absorption that tends to occur with mathematical diffusion products).

What we perceive as "precise" soundstage may also be related to a number of factors, including localization as outlined above, DR ratio again, suppressing or delaying early reflections that may randomize phase or decorrelate envelope onset, but also our perception of what Griesinger calls "proximity," since he relates this to source separation and stream segregation, so if we're able to pick out and follow a specific musical "line" or "source" (whether a singer, instrument, or orchestral section). To give a different example, perhaps we're in a relatively crowded/noisy room but able to isolate a specific speaker a la the cocktail party effect. We may cognitively anchor this with visual input, i.e. seeing the speaker. With a musical recording, do we similarly anchor this ability to isolate the individual sources to which we're paying attention at one particular time with auditory localization cues? If so, perhaps different aspects of localization may be frequency and phase dependent, so maybe three ranges in order of relative importance: below 500-1000 Hz, above 2-3 (or 4?) kHz, and 0.5-1 to 2-3 khz. Add in room/modal distortion and the intrinsic first-pass filter around 700 Hz, I think there may be an interesting correlation with typical loudspeaker crossover frequency range choices.

Young-Ho

Oh my…I am just working on “Psychoacoustics 101” course material and just got sent to the graduate level course…

Thanks for the study material…I think…

This is going to take a while to read and digest, at least whatever parts of it I will understand.