Omnidirectional speakers

[Newman]

Now I would readily concede that 18 milliseconds would be better, and I think I read somewhere a paper advocating 15 milliseconds as a standard for recording studios, BUT 10 milliseconds is presumably still a worthwhile goal in home audio, with the obvious advantage of actually being attainable.

It depends what you mean by "actually being attainable".

If you are engaging in 'audio self-harm' and sticking with stereo, then Toole shows the psychoacoustic advantage of allowing side wall reflections (bad news for dipoles, good for omnis). Well, it's pretty hard in a typical home room to get them delayed by more than 3 ms, never mind 10, or 15, or 18.

As for the rear wall (BTW that is the one behind the listener's head, as per the articles and diagrams being used on this page and quoted by Bjorn, and as per Toole's usage. It is not the one behind the speakers, despite Keith W and ShadowFiend using it that way.). Speakers of all directivities provide plenty of energy to the rear wall: it is not a point of difference. And the 10 ms delay in the diagram can only be achieved by having the wall at least 1.5m/5ft behind the listener. For a lot of us that is quite okay, but for quite a few audio listeners that will also be a problem. Nevertheless, it is not a point of difference between the speaker types under discussion.

As for the front wall, that the listener is facing, similar to the rear wall the 10 ms delay in the diagram can only be achieved by having the wall at least 1.5m/5ft behind the speaker. For a lot of us that is quite okay, but for quite a few audio listeners that will also be a problem. But even if you can do it, and have a dipole or omni that pushes sound that way, it isn't doing any good. The energy is coming from the same direction as the speakers themselves, which are already delivering plenty of direct sound from that same direction to create the desired effects of sound from that direction. The 10 ms delay avoids it doing serious harm, but you can't possibly get enough delay to do much good (although Barron, The Subjective Effects of First Reflections in Concert Halls—The Need for Lateral Reflections, 1971 demonstrates a spatial effect arising between 10 ms and 80 ms, that is for energy coming from the side. See my first para about the problem with that). Toole says the research indicates a delay of at least 80 ms in order to create envelopment effects (...and that they also need to come from other directions). Can't be done. That is why Toole recommends absorbers on that wall.

I've said it before: all this type of talk is a Stereo World Problem. The solution is cheap and widely available: multichannel speakers and a processor.

 

[Keith_W]

I've said it before: all this type of talk is a Stereo World Problem. The solution is cheap and widely available: multichannel speakers and a processor.

I agree with you, actually. One of my planned experiments is to create a multi-speaker setup to see if delayed and attenuated sound can be used to simulate reflections and enhance the feeling of spaciousness and immersion. My problem is that I have run out of DAC channels and I lack suitable speakers to try this experiment (I will need to borrow more speakers). There is an entire chapter in F. Alton Everest's "Master Handbook of Acoustics" devoted to late reflections outside the Haas fusion zone, and mentions Olive and Toole's anechoic chamber experiment with two speakers - one delivering direct sound, the other delivering the "reflection" with delay and attenuation as variables.

The question is - how would you create multichannel sound from stereo? I am planning to do it by simply copying the 2 channel signal and playing it back on extra speakers with delay and attenuation baked in. I would point the speakers away from the listening position towards the corners so that I get as much diffusion as possible. I am not sure how low the speakers need to go, my suspicion is as low as possible (need to do more reading on that). Does this seem like the right approach to you, or do you have another suggestion?

 

[jim1274]

Cheers to you too!

Yeah I recall the first time I saw that diagram - or the first time I paid close attention to it (in 2020 when I purchased the book @Bjorn found it in) - I thought it was indicating an 18 millisecond initial time-delay gap. Bummer, because most of our home audio rooms are far too small for that to be practical. But then a few days later I took second look and realized that no, the gap was actually only 10 milliseconds!

Now I would readily concede that 18 milliseconds would be better, and I think I read somewhere a paper advocating 15 milliseconds as a standard for recording studios, BUT 10 milliseconds is presumably still a worthwhile goal in home audio, with the obvious advantage of actually being attainable.

This would suggest to me, if I’m understanding correctly, that an Omni would be far more difficult to achieve adequate, let alone optimal, miilisecond delay from the side walls in a typical room, especially in a relatively narrow one like mine. A dipole reduced side wall reflective energy vs 360 dispersion seems a much better candidate to get the benefits of the reflected sound soundstage effects.

(Note that I've only been addressing the initial time-delay gap in my recent posts here; arguably the other half of the equation is getting a diffuse and spectrally-correct reflection field arriving after that time gap, decaying smoothly, and decaying neither too fast nor too slow. My opinion is that many if not most conventional monopole speakers produce a weaker-than-ideal and/or less-spectrally-correct-than-ideal "late onset" reflection field under these conditions, but concede that my opinion is in the minority.)

That conventional monopole comment mirrors what I have been hearing from my comparisons of monopoles to the dipoles and Omni soundstage. The multipolar designs have added a characteristic to the soundfield that is missing with the monopoles so far tested. What the trade-offs and sonic “penalty” are, well, that’s the question.

 

[jim1274]

It depends what you mean by "actually being attainable".

If you are engaging in 'audio self-harm' and sticking with stereo, then Toole shows the psychoacoustic advantage of allowing side wall reflections (bad news for dipoles, good for omnis). Well, it's pretty hard in a typical home room to get them delayed by more than 3 ms, never mind 10, or 15, or 18.

When you say “audio self harm” with stereo, are you suggesting stick with true discrete multi-channel recordings played through an appropriate surround sound system, or rather use some sort of DSP scheme utilizing the surround system to create the soundstage effect of say an Omni speaker?

Since the vast majority of recordings most folks listen to are only available in a stereo version, the former is not practical

As for the rear wall (BTW that is the one behind the listener's head, as per the articles and diagrams being used on this page and quoted by Bjorn, and as per Toole's usage. It is not the one behind the speakers, despite Keith W and ShadowFiend using it that way.). Speakers of all directivities provide plenty of energy to the rear wall: it is not a point of difference. And the 10 ms delay in the diagram can only be achieved by having the wall at least 1.5m/5ft behind the listener. For a lot of us that is quite okay, but for quite a few audio listeners that will also be a problem. Nevertheless, it is not a point of difference between the speaker types under discussion.

As for the front wall, that the listener is facing, similar to the rear wall the 10 ms delay in the diagram can only be achieved by having the wall at least 1.5m/5ft behind the speaker. For a lot of us that is quite okay, but for quite a few audio listeners that will also be a problem. But even if you can do it, and have a dipole or omni that pushes sound that way, it isn't doing any good. The energy is coming from the same direction as the speakers themselves, which are already delivering plenty of direct sound from that same direction to create the desired effects of sound from that direction. The 10 ms delay avoids it doing serious harm, but you can't possibly get enough delay to do much good (although Barron, The Subjective Effects of First Reflections in Concert Halls—The Need for Lateral Reflections, 1971 demonstrates a spatial effect arising between 10 ms and 80 ms, that is for energy coming from the side. See my first para about the problem with that). Toole says the research indicates a delay of at least 80 ms in order to create envelopment effects (...and that they also need to come from other directions). Can't be done. That is why Toole recommends absorbers on that wall.

Would this suggest that an optimal placement for the Omni would be equidistant from both the side and front walls to create equal delay times? I have no problem with increasing the distance to front wall, but in a long relatively narrow room the speakers gets closer and closer together to retain equidistant position as they are moved further and further from the front wall. Seems I need to do more placement experiments. I need to revisit what notes I took when initially just experimenting with Omni placement, but think I settled at about 4.5 feet from side walls and 6’ from front wall as being “good”.

I've said it before: all this type of talk is a Stereo World Problem. The solution is cheap and widely available: multichannel speakers and a processor.

Boy I sure hope this is wrong…spent 400+ hours to try and create the immersive soundstage with 2 speakers and a stereo signal…

Looks like my homework pile just got a lot taller…

I will say, prior experiments with “fake” surround using DSP modes on my multichannel surround system were not all that great, but admit I never did much experimenting. Looks like I need to revisit that. Even if that proves to be a better solution, these experiments will be useful for outdoors, actually to original reason I purchased the first Duevel Omnis in the first place.

 

[jim1274]

I agree with you, actually. One of my planned experiments is to create a multi-speaker setup to see if delayed and attenuated sound can be used to simulate reflections and enhance the feeling of spaciousness and immersion. My problem is that I have run out of DAC channels and I lack suitable speakers to try this experiment (I will need to borrow more speakers). There is an entire chapter in F. Alton Everest's "Master Handbook of Acoustics" devoted to late reflections outside the Haas fusion zone, and mentions Olive and Toole's anechoic chamber experiment with two speakers - one delivering direct sound, the other delivering the "reflection" with delay and attenuation as variables.

The question is - how would you create multichannel sound from stereo? I am planning to do it by simply copying the 2 channel signal and playing it back on extra speakers with delay and attenuation baked in. I would point the speakers away from the listening position towards the corners so that I get as much diffusion as possible. I am not sure how low the speakers need to go, my suspicion is as low as possible (need to do more reading on that). Does this seem like the right approach to you, or do you have another suggestion?

I suspect others have tried this and reported results somewhere out there in the audio forums.

I have a friend who likes to blast all his stereo recordings in 6 channel “stereo” mode through the front left and right, side surrounds, and rear surrounds. I tried it and am decididly not a fan of that approach, but it trips his trigger. I think some delay and attenuation scheme would be better, exactly what some DSP modes on an AV receiver attempt to do. Time to get my AVR manual out and throw that in the test mix, as if I needed more on my testing platter…

 

[ernestcarl]

The question is - how would you create multichannel sound from stereo? I am planning to do it by simply copying the 2 channel signal and playing it back on extra speakers with delay and attenuation baked in.

You need to invert one of the copied channels and set a level difference which when convolved will subtract or cancel out a significant portion of one channel’s content from the other but not completely to zero. Different algorithms involve different recipes. Since you already use JRiver, you could try its native upmixer.

 

[Bjorn]

Thank you Bjorn for providing the text that accompanies the diagram.

I was using the term "Reflection Free Zone" incorrectly. I was using it to refer to the time interval between the arrival of the direct sound and the early reflections. Instead, the correct definition seems to be something like "an area around the listening position within which no significant early reflections reach the listener."

The term I should have been using is "Initial Time-Delay Gap", which is the time interval between the arrival of the direct sound and the early reflections.



One would think so, BUT this is not what the diagram depicts! Look closely at the horizontal scale: 0 milliseconds is not even shown, but the arrival of the direct sound is, and assuming the horizontal scale is linear, the direct sound arrives at about 8 milliseconds.



Imo "controlling the competing early reflections from the walls, floor, and ceiling by the application of absorbers and diffusers" enables the physical space called the "reflection free zone".

These acoustic treatments create "an initial time-delay gap before the reflections from the rear wall arrive". This initial time-delay gap extends from the arrival of the direct sound at 8 miliseconds (according to the diagram) to the strong onset of the diffuse reflections at 18 milliseconds (according to the diagram).

So what I should have said was, the initial time-delay gap is 10 milliseconds.



Yes, I recall reading V. B. Pisha and Charles Billelo's two-part article on the LEDE room concept in Audio Magazine back in 1986 (it might have been 1987). I found what seems to be essentially the same article online here:

Designing a Home Listening Room (Sept. 1987)

A very similar diagram, though not identical to the one you posted, is found near the end of the article; it's a measurement made in Pisha's home listening room (which measured 19.5 by 13.5 by 8.5 feet):

View attachment 349445

Here is the caption: "Fig. 8B--Energy-time curve of Pisha's listening room of Figs. 6 and 7 after RFZ/RPG treatment, showing much improved response. An initial time-delay gap of 10 mS was created with an RFZ 24 dB below the direct sound." [emphasis mine]

It looks to me like the diagram shown in the Cox & D'Antonio book is very similar to the one in the Pisha & Bilello article, and imo BOTH diagrams are depicting an initial time-delay gap of 10 milliseconds.

(And, it looks like "10 milliseconds" as a target goes back much farther than I realized... like you said, there's little new under the sun!)

The intial scale from these old graphs are compressed in the beginning and not linear. That's seems to be the case with older graphs. We see the same thing with graphs from papers on LEDE.

You will see that at 8 ms (which you say is the direct signal) all the reflections are well attenuated and they are before that as well in the second picture below.

If the diffuse energy arrived after only 10 ms, it wouldn't have said it was arriving after 18 ms.

forming the reflection free zone described above; this extends to roughly 18 ms as shown in the lower graph in the figure.

The goal of a LEDE or LEDE/RFZ room was to extend the ISD gap at least 2 ms longer than the IDT of the recordring room (performer's area). Don Davis called this gap ISD (intital signal delay) in the studio and ITD (intial signal delay) is what it is called in the concert hall or recording room. This was required to hear all the acoustics of the performing room and which is needed for true accuracy. The distance the direct signal travels before it encounter its first audible reflection ended being the same as Beranek judged as the best concert halls, namely 20 ms.
Don Davis wrote: "
"It is no coincidence that the same 20 ms is the optimum delay for the maximum Haas effect in good, diffuse, semi-reverberant spaces."

Sure, there are studio's that are built with a shorter ISD gap due to restricted space. But the ideal is closer to 20-25 ms. Here's the ETC of a LEDE room in Sweden.

There were also guidelines for speakers in a LEDE room. Take a look at how good the polar of a speaker from the 80s was.

The decades up the 80s was very much the golden area of researchers into studios and psycoacoustics. We have better software and measuring gear today, but IMO the knowledge in the right circles was higher back then.

 

[youngho]

The intial scale from these old graphs are compressed in the beginning and not linear. That's seems to be the case with older graphs. We see the same thing with graphs from papers on LEDE.

The time axis looks extremely linear with the same distance between 10-20 ms and 20-30 ms, so it would be quite remarkable to interpret the distance between the Y-axis line, which is not labelled as zero, and the 10 ms mark as compression.

You will see that at 8 ms (which you say is the direct signal) all the reflections are well attenuated and they are before that as well in the second picture below.

The graph is labelled as "direct sound," so it's not just @Duke saying it's direct signal.

If the diffuse energy arrived after only 10 ms, it wouldn't have said it was arriving after 18 ms.

Unless someone made a mistake. It happens. I pointed out some labelling problems in Sean Olive's presentations on headphones, also I found one in Toole's characterization of listener target preferences in "The Measurement and Calibration of Sound Reproducing Systems."

The distance the direct signal travels before it encounter its first audible reflection ended being the same as Beranek judged as the best concert halls, namely 20 ms.

The three A+ halls in "Concert and Opera Halls" are Amsterdam Concertgebouw (ITDG 21 ms), Boston Symphony Hall (15 ms), Vienna Grosser Musikvereinssaal (12 ms).

 

[Blockader]

Hi Duke, would you be able to educate me on this one, because I don't know. How do dipoles create nulls on the sides? I was under the impression that it is due to cancellation from the out of phase front and back waves interacting where they meet at the side? If so, what happens to a dipole's radiation pattern if a wall interferes with it?

When an omnidirectional source encounters another omnidirectional source facing it with reversed polarity, they cancel each other out on both sides. This phenomenon can be visualized and is supported by mathematical explanations.

left is monopole, right is dipole.

This cancellation makes the directivity index of dipole speakers equal or almost equal to full range cardioid speakers.
The downside is, dipole speakers roll off faster than monopole speakers below their tuning frequency, indicating that dipoles are not as efficient in bass delivery- But they are quite controlled in their dispersion pattern in low frequencies.

Dipole panel speakers have aser-like directivity at high frequencies, minimizing ceiling and floor reflections almost entirely. This leads to incredible clarity unmatched by other types of speakers but also makes their sweet spot extremely narrow. They may also sound unnatural because human hearing sounds fused with floor reflections.

 

[Bjorn]

The time axis looks extremely linear with the same distance between 10-20 ms and 20-30 ms, so it would be quite remarkable to interpret the distance between the Y-axis line, which is not labelled as zero, and the 10 ms mark as compression.

The graph is labelled as "direct sound," so it's not just @Duke saying it's direct signal.

Unless someone made a mistake. It happens. I pointed out some labelling problems in Sean Olive's presentations on headphones, also I found one in Toole's characterization of listener target preferences in "The Measurement and Calibration of Sound Reproducing Systems."

The three A+ halls in "Concert and Opera Halls" are Amsterdam Concertgebouw (ITDG 21 ms), Boston Symphony Hall (15 ms), Vienna Grosser Musikvereinssaal (12 ms).

The book clearly states diffusion arrives after 18 ms, meaning the direct signal has to start at 0 ms. So there's isn't much discuss here. Graphs from that time looks like this though.

We also know well that LEDE/RFZ design required a longer ISD then 10 ms as I have explained Let's not argue for the sake of argument.

 

[xschop]

If one were to build a two-way omni-directional speaker (upward firing, stacked drivers) from an already existing 2-way forward firing box design, would the crossover have to be changed much, and how?
Thanks for all the great reading here.

 

[Duke]

The book clearly states diffusion arrives after 18 ms, meaning the direct signal has to start at 0 ms. So there's isn't much discuss here. Graphs from that time looks like this though.

We also know well that LEDE/RFZ design required a longer ISD then 10 ms as I have explained Let's not argue for the sake of argument.

I'm not arguing about what constitutes best practices for LDE/RFZ studio control room design. Recall that your graph is from a "small critical listening room", so presumably it is showing what can be accomplished in a small room.

I'm disagreeing with your analysis of that particular graph. I think the graph is linear, and it does not show 0 milliseconds because the time-gated microphone would not have picked anything up at 0 milliseconds since this was when the signal left the loudspeaker. I use time gating routinely, and you probably do too, and the time that the signal arrives at the microphone is never 0 milliseconds.

To put it another way, yes the diffuse reflections arrive after 18 milliseconds, but 18 milliseconds after what? After the direct sound, or after the signal leaves the loudspeaker? When does the horizontal axis in the measurement graph start scrolling? Is it when the direct sound reaches the microphone, or when the measurement system tells the amplifier to send the test signal to the loudspeaker?

I've ordered a replacement copy of Cox & D'Antonio's book, so that I will be going less by my suppositions.

What is your analysis of this graph which is very similiar to yours, shown near the bottom of the Pisha & Bilello article, whose caption clearly states that the time gap is 10 milliseconds? Here they are so you don't have to scroll back to post number 338:

Caption: "Fig. 8B--Energy-time curve of Pisha's listening room of Figs. 6 and 7 after RFZ/RPG treatment, showing much improved response. An initial time-delay gap of 10 mS was created with an RFZ 24 dB below the direct sound." [emphasis mine]

Link: https://www.gammaelectronics.xyz/audio_08-1987_room.html#google_vignett

If one were to build a two-way omni-directional speaker (upward firing, stacked drivers) from an already existing 2-way forward firing box design, would the crossover have to be changed much, and how?

The crossover would have to be changed. You'd no longer be remotely close to on-axis of the drivers, whose radiation patterns would be changinging with frequency. Without some sort of diffusor (like Duevel uses) the direct sound at the listening position would be very poor.

 

[xschop]

I'm not arguing about what constitutes best practices for LDE/RFZ studio control room design. Recall that your graph is from a "small critical listening room", so presumably it is showing what can be accomplished in a small room.

I'm disagreeing with your analysis of that particular graph. I think the graph is linear, and it does not show 0 milliseconds because the time-gated microphone would not have picked anything up at 0 milliseconds since this was when the signal left the loudspeaker. I use time gating routinely, and you probably do too, and the time that the signal arrives at the microphone is never 0 milliseconds.

To put it another way, yes the diffuse reflections arrive after 18 milliseconds, but 18 milliseconds after what? After the direct sound, or after the signal leaves the microphone?

I've ordered a replacement copy of Cox & D'Antonio's book, so that I will be going less by my suppositions.

What is your analysis of this graph which is very similiar to yours, shown near the bottom of the Pisha & Bilello article, whose caption clearly states that the time gap is 10 milliseconds? Here they are so you don't have to scroll back to post number 338:

View attachment 349618

Caption: "Fig. 8B--Energy-time curve of Pisha's listening room of Figs. 6 and 7 after RFZ/RPG treatment, showing much improved response. An initial time-delay gap of 10 mS was created with an RFZ 24 dB below the direct sound." [emphasis mine]

Link: https://www.gammaelectronics.xyz/audio_08-1987_room.html#google_vignett



The crossover would have to be changed. You'd no longer be remotely close to on-axis of the drivers, whose radiation patterns would be changinging with frequency. Without some sort of diffusor (like Duevel uses) the direct sound at the listening position would be very poor.

So would a coaxial driver with tweeter in center be more ideal? Like using a KEF driver?

 

[Duke]

So would a coaxial driver with tweeter in center be more ideal? Like using a KEF driver?

What are you doing to transition the sound coming from the speaker, in particular the shorter wavelengths, from directional to omnidirectional in the horizontal plane? Imo figuring out how you're going to address that issue comes before driver choice.

 

[Duke]

It depends what you mean by "actually being attainable".

If you are... sticking with stereo, then Toole shows the psychoacoustic advantage of allowing side wall reflections (bad news for dipoles, good for omnis). Well, it's pretty hard in a typical home room to get them delayed by more than 3 ms, never mind 10, or 15, or 18.

My preference is for minimizing early side-wall reflections, as I think they degrade image precision and soundstage depth. They can be delayed by 10 milliseconds or so in a normal room but it calls for an unconventional approach which relies on speaker directivity. I don't think this thread is the place for me to go into detail about my approach.

Speakers of all directivities provide plenty of energy to the rear wall: it is not a point of difference. And the 10 ms delay in the diagram can only be achieved by having the wall at least 1.5m/5ft behind the listener. For a lot of us that is quite okay, but for quite a few audio listeners that will also be a problem. Nevertheless, it is not a point of difference between the speaker types under discussion.

Agreed.

As for the front wall, that the listener is facing, similar to the rear wall the 10 ms delay in the diagram can only be achieved by having the wall at least 1.5m/5ft behind the speaker... The energy is coming from the same direction as the speakers themselves,

Again loudspeaker directivity can play a beneficial role in manipulating front-wall reflection strengths, arrival times, and arrival directions.

The 10 ms delay avoids it doing serious harm, but you can't possibly get enough delay to do much good (although Barron, The Subjective Effects of First Reflections in Concert Halls—The Need for Lateral Reflections, 1971 demonstrates a spatial effect arising between 10 ms and 80 ms, that is for energy coming from the side. See my first para about the problem with that). Toole says the research indicates a delay of at least 80 ms in order to create envelopment effects (...and that they also need to come from other directions). Can't be done. That is why Toole recommends absorbers on that wall.

If the desired reflections and their delays are already on the recording (and presumably they are), then arguably the role of the loudspeakers-and-room is to present that aspect of the recording effectively enough for it to be perceptually dominant. This is sometimes referred to as a "you are there" presentation.

I've said it before: all this type of talk is a Stereo World Problem. The solution is cheap and widely available: multichannel speakers and a processor.

But wouldn't it be nice for some people if there was ALSO a two-channel solution which only needed the venue spatial cues already present on the recording, instead of relying on the relatively small selection of multi-channel recordings and/or a processor whose settings might need to be adjusted from one recording to the next?

 

[xschop]

What are you doing to transition the sound coming from the speaker, in particular the shorter wavelengths, from directional to omnidirectional in the horizontal plane? Imo figuring out how you're going to address that issue comes before driver choice.

 

[Duke]

@xschop, VERY NICE!!

Imo you will need a lot more top-end energy to cover 360 degrees than what home-audio coaxials tend to put out. Imo something from the prosound world would make more sense. Prosound coaxials do not tend to go very deep so you will probably need a dedicated woofer or subwoofer section.

In an 8" coaxial, I suggest the Faital 8HX200:

Loading…

faitalpro.com

 

[jim1274]

If one were to build a two-way omni-directional speaker (upward firing, stacked drivers) from an already existing 2-way forward firing box design, would the crossover have to be changed much, and how?
Thanks for all the great reading here.

Do you mean like Duevel does in all their up-models above the Planets and Enterprise I am using for my testing comparisons?

Those models use that stacked drivers design if I understood you correctly:

Duevel Venus - omnidirectional highend home-audio speaker

the only one high-end audio horn-speakers with a perfect omnidirectional character, like the acoustical ideal of a point source, with a new quality of natural music reproduction.

www.duevel.com

 

[jim1274]

So would a coaxial driver with tweeter in center be more ideal? Like using a KEF driver?

I was wondering why Duevel didn’t do something like that myself.

It would seem that having both drivers on the same vertically aligned axis makes the most sense, exactly what Duevel does in all the higher models in their line. I suspect using side by side mid-woofer and tweeters in the lower end models was a cost saving issue?

It’s interesting how they use 2 completely different dispersion designs on these two models—another cost measure with balls being cheaper implementation on the entry level Planets?

 

[jim1274]

The three A+ halls in "Concert and Opera Halls" are Amsterdam Concertgebouw (ITDG 21 ms), Boston Symphony Hall (15 ms), Vienna Grosser Musikvereinssaal (12 ms).

Just checked the stereo source DSP program surround options for my Yamaha surround receiver—two of the three you noted are included:

Amsterdam
Vienna

Other available ones:
Freiburg Church
Munich Hall
Royaumont Church
Chamber
Village Vanguard
Warehouse Loft
Cellar Club
Roxy Theater
The Bottom Line
9 channel stereo

Maybe my soundstage immersion and such problem has just been solved? Will know soon, plus the surround and 2 channel systems are seperate so easy to do instant level matched A/B comparison.