omnidirectional loudspeakers = best design available

[oivavoi]

They are generally recording and mastering stereo music with the expectation that it will be listened to in stereo. I understand that you're not using the same speakers and aren't in the same room, but I disagree that the whole stereo baby can be thrown out with the bathwater under the guise that the audio reproduction setup isn't EXACTLY the same.

But omni is still stereo though! The difference is that you get more indirect sound, compared to the direct sound (at least if you sit a bit away from the speakers), but this indirect sound is then much more similar to the direct sound. With coventional speakers you get somewhat less indirect sound (again, sitting away from the speakers), but you still get lots of indirect sound, and this indirect sound will be very different from the direct sound.

So which one is more correct? I don't think it's obvious, to be honest.

I see this as a matter of degree. It's similar to the debate on wide vs narrow dispersion with conventional box speakers. Which one is better? Both has their use, I think. I see if of different flavors of the same cake.

Fwiw, my own preference is to listen to wide-dispersion speakers (in the future possibly omnis) in the near-field. That way one gets much late indirect sound which is similar to the direct sound, but the direct sound still dominates the perception and creates good stereo images.

 

[Duke]

I'm familiar with the M3si, baby brother of the M1. They weren't really close to omnidirectional. Bidirectional and probably wider dispersion than usual is how I'd describe the polar pattern.

I agree with your description. The M-1's were bi-directional.

You need to rationalize how music that is recorded and mastered specifically for STEREO REPRODUCTION would or could benefit by being reproduced on an Omni speaker. You definitely aren't listening to the sound that the mastering engineer was.

Let me quote from a post by a retired recording engineer, from another forum:

"As a retired recording engineer, I can tell you first hand that studio and home setups are as different as chalk and cheese.

"In the studio, we don’t listen to music. We listen to instruments, voices and mixes.

"B I G difference."

A well-energized reverberant field in the mixing room is COUNTER-PRODUCTIVE to what the recording engineer is trying to do. Now let's look at how music is presented in a good venue, like a recital hall or a concert hall.

1. First you have a clear stream of direct sound.

2. Then you have a time gap which is largely free from early reflections.

3. Then you have a well-energized, spectrally-correct stream of reverberant energy which arrives from all directions and which decays rather slowly.

In my opinion THAT situation is also a worthy goal for music playback. So I think this is where we disagree:

I think your priority is replicating what the recording engineer heard.

And I cannot speak for oivavoi [who posted similar thoughts while I was typing] or MattHooper, but my priority is replicating the perception of hearing live music.

To you perhaps these two priorities are synonymous, but to me they are not.

Whether or not you agree with my analysis of where our priorities diverge, I request that you not resort to innuendoes and name-calling. If your science is good, it can stand on its own without that sort of thing.

 

[oivavoi]

If Omnidirectional speakers produced better sounding music playing the market heavily produced stereo recorded/mastered music then large companies would definitely be interested in releasing new products to capitalize on that advantage. Hell, they already try to capitalize on any unreal advantages to the best of their abilities by making all sorts of weird design choices. Let's not pretend that it's uncommon for someone to run an audio company that's heavily based on "woo" while claiming sonic superiority.

Just following up on this (I think you edited it in afterwards):
There are actually large companies pushing omni or omni-ish designs. But they do it in the consumer entry-level products. Apple does it with the homepod (quasi-omni), Samsung with several of their wireless speakers, Harman Kardon as well with one of their speakers. Most of the commercial audio research these days goes into these kind of products, so I think there must have been some testing leading them to go in that direction. Samsung actually has one of the largest audio research facilities at the moment. They stole quite a lot of smart folks form Harman. But their speakers are not comparable to any of the high-end true omnis of course.

As to why there haven't been any commercial attempts at omnis in the high-end, I think that WAF factors have a lot to do with it. Omnis need air, and should be placed one meter from walls. That's a tough call in most homes. Similarly, horns generally benefit from being large. But almost all commercial offerings with compression drivers etc have fairly small waveguides. I can't think of any really big horn offerings from the larger companies. But it's not because it's acoustically superior (it's not), but because that's what it's possible to sell.

Here's the current system of Bjørn Kolbrek, probably the biggest authority of horn loudspeakers:

The reason those beasts are not sold by klipsch or harman is not because current klipsch waveguides are better (far from it), but because Klipsch assumes that they would not be able to sell many such speakers.

 

[Harmonie]

Conceptually, the Walsh invention would seem hold the most promise, as it consists of a single driver for mids and highs. Ohm never really got it to work as advertised. Morrison is a variation of the Hegeman design. Three way (I think) with passive crossover, conventional mid and HF drivers firing up into a spherical lens.

The MBL site is not exactly forthcoming with technical information, but the large speakers appear to be multidriver with crossovers. Interestingly they claim their wave launch is 180 degrees, but the drivers appear 360. MBL literature mimics the Amar Bose idea of direct/reflective concert hall thing.

Their large speakers are shown in huge 'living rooms' and I imagine that in such large open spaces the speakers do present an impressive sonic artifact. I'm guessing that many ASR readers have smaller listening rooms, and are using the small monitor-type speakers reviewed here, in a nearfield listening position, or possibly larger floor standing speakers in a more normal sized living room.

But consider, if you have twenty or thirty thousand cubic feet of space to fill, small boxes, or even larger floor standing conventional loudspeakers just aren't going to fill the bill. So what are you supposed to do? Obviously in such an environment you are not going to employ a 'critical listening' monitor in an attempt to 'recreate' whatever the recording engineer heard at his console location. But that is not what the buyer of these is probably looking for, in such a large space, is it?

View attachment 104125

Why are such omnis placed against the wall ?

 

[Duke]

@Shazb0t, would you have any interest in conducting a listening test of your own?

I realize this is a long shot because you recently posted that "subjective claims, like the "testing" you've performed, aren't just worthless, but in this specific scenario are also completely illogical." So it would be inconsistent for you to conduct a subjective listening test on an illogical scenario.

But if this is something you might consider, let me know.

 

[MattHooper]

So the "testing" that you did was able to show that music recorded and mastered in stereo played back on an Omni speaker was like "being at the live performance"? How exactly does that magic work? My point is subjective claims, like the "testing" you've performed, aren't just worthless, but in this specific scenario are also completely illogical. You don't have to agree with me.

There's a reason that science based speaker design and engineering teams with large corporate budgets and a desire to outperform their peers in a highly competitive market aren't pursuing the current Omni speaker technology for stereo reproduction. It's not a conspiracy to stick us all with bad sounding music. You know, Occam's razor and all.

Well, you don't seem to be in a state of mind to take what anyone else says seriously.

But, it was your contention that omnis were fundamentally ill-suited to reproduce the original performance. I've at least had SOME experience testing that claim, at least for myself. I didn't just have a recording of an instrument to reproduce; I had the actual instrument (and voices), to see how the reproduced sound compared to the sound of the actual instrument the microphone recorded. And I often even did live-vs-reproduced comparisons with various speakers - playing a recording of my son's voice, then comparing it with him actually speaking in the same room.
Same with his saxophone. Same with my acoustic guitar, etc.

And I found that omni reproduced the sound of the "live" instrument most like the live instrument itself sounded.

I'm clearly not going to convince you of anything nor will I try. Just offering another bit of data input, in terms of reported experience, on this subject.

 

[Sancus]

A big problem for me with this idea that omnis are the ideal speaker is that stereo is an inherently compromised form of audio reproduction. At the end of the day, all forms of wide++ dispersion stereo speakers are trying to add ambience that isn't present in the original recording, by way of bouncing more sound off walls and adding extra reflections.

There's nothing wrong with that -- I personally am not interested in obsessing over the intent of the artist/mixer as the circle of confusion makes it far too difficult to reach any meaningful conclusion. Though I'll tend to agree that a pair of moderate to low dispersion loudspeakers in a somewhat absorptive, treated room is more likely to match up with that intent than any exotic speaker design.

Accepting that the goal here is to make things sound subjectively better and NOT to exactly duplicate the sound of the recording, then personally it makes far more sense to me to directly control the reflections via having a large number of narrow dispersion speakers in multi-channel. That way you skip the whole room interaction part as much as possible. And in addition, you can very easily adjust the amount of reflections you want based on the type of music(if using upmixing). With multi-channel sources the sound engineers can even directly control the character of all reflections much more precisely.

 

[oivavoi]

Accepting that the goal here is to make things sound subjectively better and NOT to exactly duplicate the sound of the recording, then personally it makes far more sense to me to directly control the reflections via having a large number of narrow dispersion speakers in multi-channel. That way you skip the whole room interaction part as much as possible. And in addition, you can very easily adjust the amount of reflections you want based on the type of music(if using upmixing). With multi-channel sources the sound engineers can even directly control the character of all reflections much more precisely.

I agree that multichannel probably is the ideal solution. True acoustic Auro 3d recordings come very close to the original idea of high-fidelity, to transfer the soundfield of the recording room to the playback room. I hope that there is a kick-ass auro 3d setup in my future. (in addition to a pair of omnis for the living room where the wife will never accept 13 loudspeakers)

 

[nerdoldnerdith]

I think we're speaking across terms here, in multiple ways.

When OP, others, and I refer to omnidirectional speaker designs, we are referring to very specific dispersion pattern that only a tiny handful of speakers, mostly from niche companies, actually reproduce. This type of omnidirectional speaker is *not* simply a speaker that spits out sound in every direction; it is a speaker that has the exact same frequency response at least 360 degrees horizontally but ideally 360 degrees both horizontally and vertically. There is no speaker that does 360 degrees vertically, but the closest thing is the Morrison Audio speaker that does 180 degrees. Bipoles, dipoles, baffle-less designs, wide-dispersion designs, designs that are omni up to a certain frequency, designs that fire backwards, etc. are not omnidirectional speakers in this category, and they will not reproduce a sound field anything like true omnidirectional speakers do. An omnidirectional speaker sounds like live music playing in one's room because it approximates the same radiation pattern as live music being played in one's room, which is collectively omnidirectional. Anything else will not have that same effect and will produce an audible mismatch between how live music ought to sound in the room and the pattern being produced by the speakers.

When we talk about the experience of live music, we are talking about creating the illusion that the band itself is in your listening room, with the sounds of their instruments and voices bouncing around the acoustic environment exactly like the instruments' sounds would do if they were literally in the room. We are not talking about recreating the experience of going to a live concert and sitting in a concert hall. When this is successfully done, as it is with the Morrison Audio speakers, it creates a true sonic hologram of music with surgical precision and accuracy to the source, because the speakers are giving your ears complete and accurate information about where sound is being produced in the recording. This could not be more different than the cheap effect you get by bouncing sound every which way around your room.

 

[Shazb0t]

@Shazb0t, would you have any interest in conducting a listening test of your own?

I realize this is a long shot because you recently posted that "subjective claims, like the "testing" you've performed, aren't just worthless, but in this specific scenario are also completely illogical." So it would be inconsistent for you to conduct a subjective listening test on an illogical scenario.

But if this is something you might consider, let me know.

What do you propose?

 

[Sancus]

I think we're speaking across terms here, in multiple ways.

When OP, others, and I refer to omnidirectional speaker designs, we are referring to very specific dispersion pattern that only a tiny handful of speakers, mostly from niche companies, actually reproduce. This type of omnidirectional speaker is *not* simply a speaker that spits out sound in every direction; it is a speaker that has the exact same frequency response at least 360 degrees horizontally but ideally 360 degrees both horizontally and vertically.

Whether or not the frequency response of the off-axis sound is bad or not doesn't change the fact that you're bouncing sound off the walls to produce reflections. You don't have actual sound sources at those angles. I completely agree that if the off-axis frequency response of an omni is bad, then the situation is even worse, not only are your reflections heavily affected by the room but they're going to sound wrong to start with.

But even a perfect omni is still bouncing sound around.

I agree that multichannel probably is the ideal solution. True acoustic Auro 3d recordings come very close to the original idea of high-fidelity, to transfer the soundfield of the recording room to the playback room. I hope that there is a kick-ass auro 3d setup in my future. (in addition to a pair of omnis for the living room where the wife will never accept 13 loudspeakers)

Yeah I think if you're limited to a certain # of speakers, omnis may very well be a good idea. I am somewhat surprised that none of the popular smart speakers have gone this direction, while they're mostly very wide dispersion I don't think any of them are truly omnidirectional. Actually I'm wrong about this the Apple Homepod is clearly trying to be an omni with 360 degree dispersion up to 10K horizontally. Perhaps it is just impractical for now -- the only speakers that seem to come anywhere close to the ideal seem to be extremely expensive. And even then, no one has produced any real measurements of these Morrison speakers to prove that their performance is anywhere near what is claimed, so those claims are highly suspect to me.

 

[Shazb0t]

But omni is still stereo though! The difference is that you get more indirect sound, compared to the direct sound (at least if you sit a bit away from the speakers), but this indirect sound is then much more similar to the direct sound. With coventional speakers you get somewhat less indirect sound (again, sitting away from the speakers), but you still get lots of indirect sound, and this indirect sound will be very different from the direct sound.

So which one is more correct? I don't think it's obvious, to be honest.

I see this as a matter of degree. It's similar to the debate on wide vs narrow dispersion with conventional box speakers. Which one is better? Both has their use, I think. I see if of different flavors of the same cake.

Fwiw, my own preference is to listen to wide-dispersion speakers (in the future possibly omnis) in the near-field. That way one gets much late indirect sound which is similar to the direct sound, but the direct sound still dominates the perception and creates good stereo images.

This is an interesting concept to me because I obviously have not thought about it this way. In your opinion, knowing the reproduction at the end of the chain is going to be a single (Or pair? Or triplet? How do you decide?) of omni speakers, what would the ideal way of recording and mastering the performance be? Would you do everything the same as how stereo music is currently recorded and mastered? I'm interested.

Well, you don't seem to be in a state of mind to take what anyone else says seriously.

But, it was your contention that omnis were fundamentally ill-suited to reproduce the original performance. I've at least had SOME experience testing that claim, at least for myself. I didn't just have a recording of an instrument to reproduce; I had the actual instrument (and voices), to see how the reproduced sound compared to the sound of the actual instrument the microphone recorded. And I often even did live-vs-reproduced comparisons with various speakers - playing a recording of my son's voice, then comparing it with him actually speaking in the same room.
Same with his saxophone. Same with my acoustic guitar, etc.

And I found that omni reproduced the sound of the "live" instrument most like the live instrument itself sounded.

I'm clearly not going to convince you of anything nor will I try. Just offering another bit of data input, in terms of reported experience, on this subject.

I'm not a supervillain, I promise. I agree that we aren't going to convince each other. I also respect your right to a subjective opinion. My problem with this thread is that the OP was very absolute in his statements and as we both know, only Sith deal in absolutes. I may be projecting that belief too much on some of you, I apologize for that.

A big problem for me with this idea that omnis are the ideal speaker is that stereo is an inherently compromised form of audio reproduction. At the end of the day, all forms of wide++ dispersion stereo speakers are trying to add ambience that isn't present in the original recording, by way of bouncing more sound off walls and adding extra reflections.

There's nothing wrong with that -- I personally am not interested in obsessing over the intent of the artist/mixer as the circle of confusion makes it far too difficult to reach any meaningful conclusion. Though I'll tend to agree that a pair of moderate to low dispersion loudspeakers in a somewhat absorptive, treated room is more likely to match up with that intent than any exotic speaker design.

Accepting that the goal here is to make things sound subjectively better and NOT to exactly duplicate the sound of the recording, then personally it makes far more sense to me to directly control the reflections via having a large number of narrow dispersion speakers in multi-channel. That way you skip the whole room interaction part as much as possible. And in addition, you can very easily adjust the amount of reflections you want based on the type of music(if using upmixing). With multi-channel sources the sound engineers can even directly control the character of all reflections much more precisely.

I wholeheartedly agree with this. If the OP had been espousing the superiority of properly recorded/mastered mulitchannel music against stereo it would have been a much more interesting post IMO.

I think we're speaking across terms here, in multiple ways.

When OP, others, and I refer to omnidirectional speaker designs, we are referring to very specific dispersion pattern that only a tiny handful of speakers, mostly from niche companies, actually reproduce. This type of omnidirectional speaker is *not* simply a speaker that spits out sound in every direction; it is a speaker that has the exact same frequency response at least 360 degrees horizontally but ideally 360 degrees both horizontally and vertically. There is no speaker that does 360 degrees vertically, but the closest thing is the Morrison Audio speaker that does 180 degrees. Bipoles, dipoles, baffle-less designs, wide-dispersion designs, designs that are omni up to a certain frequency, designs that fire backwards, etc. are not omnidirectional speakers in this category, and they will not reproduce a sound field anything like true omnidirectional speakers do. An omnidirectional speaker sounds like live music playing in one's room because it approximates the same radiation pattern as live music being played in one's room, which is collectively omnidirectional. Anything else will not have that same effect and will produce an audible mismatch between how live music ought to sound in the room and the pattern being produced by the speakers.

When we talk about the experience of live music, we are talking about creating the illusion that the band itself is in your listening room, with the sounds of their instruments and voices bouncing around the acoustic environment exactly like the instruments' sounds would do if they were literally in the room. We are not talking about recreating the experience of going to a live concert and sitting in a concert hall. When this is successfully done, as it is with the Morrison Audio speakers, it creates a true sonic hologram of music with surgical precision and accuracy to the source, because the speakers are giving your ears complete and accurate information about where sound is being produced in the recording. This could not be more different than the cheap effect you get by bouncing sound every which way around your room.

As you said, you're referring to an ideal point source loudspeaker. I have never seen one. I'm not convinced that Morrison Audio, which you already admit is 180 degrees off this ideal, is capable of flat even sound in the 180 degree sphere that it claims. Feel free to send one to Amir for measurement to prove that it is. This thread would read as less of an ad for Morrison Audio if one of you guys with these speakers manned up!

 

[Duke]

Bipoles, dipoles, baffle-less designs, wide-dispersion designs, designs that are omni up to a certain frequency, designs that fire backwards, etc. are not omnidirectional speakers in this category, and they will not reproduce a sound field anything like true omnidirectional speakers do.

Agreed.

An omnidirectional speaker sounds like live music playing in one's room because it approximates the same radiation pattern as live music being played in one's room, which is collectively omnidirectional.

I understand that line of thinking. I owned omnis for many years.

When we talk about the experience of live music, we are talking about creating the illusion that the band itself is in your listening room.

This is ONE VERSION of creating the illusion of live music. This might be called the "They Are Here" experience.

We are not talking about recreating the experience of going to a live concert and sitting in a concert hall.

Actually this is exactly what I'm talking about. It is the OTHER VERSION of creating the illusion of live music, and might be called the "You Are There" experience.

I'm not saying the one's right and the other's wrong, but they are different end goals that call out different priorities.

When this is successfully done, as it is with the Morrison Audio speakers, it creates a true sonic hologram of music with surgical precision and accuracy to the source, because the speakers are giving your ears complete and accurate information about where sound is being produced in the recording. This could not be more different than the cheap effect you get by bouncing sound every which way around your room.

For what it's worth, Don Morrison and I think we're close enough to being "on the same page" that we're friends. If you'd like, I can offer an explanation as to why the polydirectional approach I advocate isn't a "cheap effect".

 

[oivavoi]

In your opinion, knowing the reproduction at the end of the chain is going to be a single (Or pair? Or triplet? How do you decide?) of omni speakers, what would the ideal way of recording and mastering the performance be? Would you do everything the same as how stereo music is currently recorded and mastered? I'm interested.

Good question. Concerning studio-generated electronic music I would probably add less reverb. There was a study done some time ago which showed that mastering engineers in lively control rooms add less reverb than mastering engineers in dry control rooms. That makes sense, as reverb is a way of compensating for the lack of reflections, and vice versa. It's reasonable to assume that omni speakers can benefit from drier recordings. But this is only conjecture on my part, given that I havent owned any omnis in my home, so I havent had the time to compare.

I'm not a supervillain, I promise.

I believe you!

This thread would read as less of an ad for Morrison Audio if one of you guys with these speakers manned up!

I actually proposed to Don Morrison to send one of his speakers to Amir. Still waiting on my pair to get finished, but when they do get finished I have thought about making Amir a stopgap, if he's interested and they haven't been measured by then.

 

[EJ3]

my priority is replicating the perception of hearing live music.

SAME!

 

[Duke]

I'm not a supervillain, I promise. I agree that we aren't going to convince each other. I also respect your right to a subjective opinion. My problem with this thread is that the OP was very absolute in his statements and as we both know, only Sith deal in absolutes. I may be projecting that belief too much on some of you, I apologize for that.

You didn't direct that at me, but I thank you.

What do you propose?

Do you have a second pair of speakers which you could easily move into the same room and same system as your main speakers?

What I have in mind is, place the secondary speakers on the floor behind the main speakers, facing up, hopefully with the main speakers shielding the secondary speakers so that they do not have a direct sound path to the listening area. Then listen to both sets simultaneously, vs just your original speakers, ideally adjusting the volume level such that the secondary speakers don't convey an unfair SPL advantage.

This would be far from an ideal polydirectional setup, and I have no idea what your system is like so I have no idea whether it's even feasible.

If this does what I expect, the loudspeakers will be less apparent as the sound source with the secondary speakers on, and you'll have a bit more sense of envelopment in the acoustic space on the recording. Timbre may or may not be improved. The tonal balance may become overly thick in the upper bass and lower midrange region. I also expect image specificity and overall clarity to be degraded... optimization isn't practical for this experiment.

Let me know if you have any questions.

And, thank you for considering this, even if you decide against it.

 

[mhardy6647]

What is the optimal number of omni speakers to have in a room?

It's either one, zero, or infinite. Pretty sure it is one of those three.
I will run some simulations and get back to all y'all on this.

 

[Newman]

Imo omnis do some things very well and some things not so well... Imo one thing a good omni NAILS is, getting the spectral balance of the reverberant field spot-on. I am well aware that the approach preferred around here is for the direct sound to be flat and for the room response to be gently downward-sloping, rather than them both being identical. Imo this preferred approach is making a virtue of necessity: It is inevitable that conventional cone-n-dome speakers will beam, therefore it is inevitable that the off-axis response will be rolled-off somewhat relative to the on-axis response. Having tried it both ways, I find merit in minimizing the spectral discrepancy between the direct and reflected sound.

...To those inclined to scoff at omnis, do you recall which speaker was Floyd Toole's choice from among all the speakers tested at the NRC in Canada, or how fondly he spoke of it in the third edition of his book (page 190)? No it wasn't a true omni, but it wasn't far off either....

Your words, “the approach preferred around here”, is actually the approach that listeners prefer, coming out of the research.

And, as for Toole’s Mirage M1 that you (repeatedly in this thread) mention, you are leaving out critical context: he wrote that he had (mis?)-conceived of a listening room in his home that turned out to be horrendous, virtually a giant echo chamber that just plain sounded bad, and his domestic situation made acoustic treatment impossible. And when he tried to use the room to play classical music of the time which, he said, was too-often horrendously poorly recorded and placed large sections of the orchestra wholly in one speaker, he needed a loudspeaker that was really bad at soundstage reproduction and greatly blurred the sonic image. Enter the Mirage M1. Which he promptly left behind when he sold the house, never intending to have such a room again. Context.

 

[Newman]

Live music and therefore sound propogation happens omnidirectionally, and is how our ear-brain mechanisms have evolved to understand sound.

A musical instrument (acoustic) is more omni than directional. So you will always get a lot of ambient sound from a musical instrument--a sound 'quality' that will just not be present from a directional point source.

When we talk about the experience of live music, we are talking about creating the illusion that the band itself is in your listening room, with the sounds of their instruments and voices bouncing around the acoustic environment exactly like the instruments' sounds would do if they were literally in the room.

Might as well kill 3 birds with one stone.

If I stand in front of you and talk, my voice is not anything like omnidirectional, and if I play a violin or guitar or clarinet while standing there, its music is also not omnidirectional, not even close. So, if an omnidirectional speaker is placed where I am standing and plays a recording of my speech and instrumental playing, and redirects all the sound omnidirectionally, that loudspeaker is performing a gross reproductive inaccuracy. An act of high unrealism.

The whole idea that omnidirectional playback is correct, or ideal, is a myth.

Here are the actual directivity vs frequency plots of voice and various instruments, © Toole:

The fact that they are not all the same means that no one loudspeaker can be perfect at reproducing all their directionalities. However, in broad and general terms, the speaker type that does best at reproducing the directionality of some of the most critical original sources such as voice, string and wind instruments, is ..... your typical front-firing loudspeaker that trends to omnidirectional in the bass!

(P.S. An omnidirectional speaker is a flat line on the zero axis at the bottom of the above chart. Pretty bad eh?)

So, if we compare the human voice directivity curve, above, to some forward-firing loudspeakers © Toole:

Again, imagine an omnidirectional loudspeaker on the above graph as a flat line on the zero axis. We can easily see that various conventional loudspeakers on the graph are far superior to an omnidirectional at reproducing something approaching the directivity of a human voice in a natural way. Furthermore, if we imagine adding the various other instruments from the top graph onto the bottom chart, we see the conventional loudspeakers even better at matching their directivities, and the omnidirectional even worse again. In fact, the omnidirectional is completely uncompetitive at the one feature that has been promoted as its natural advantage.

Thus we see that all the above arguments that idealise the directivity of omnidirectional loudspeakers, are based on a false premise, which changes all your conclusions.

Cheers

 

[BenB]

It's either one, zero, or infinite. Pretty sure it is one of those three.
I will run some simulations and get back to all y'all on this.

This may be a joke, but I see a lot of truth to it. If we are to approximate the dispersion of most sound sources as omni (even though there's evidence this is wrong), and if we want to re-create the experience of having those sound sources in front of us authentically, we need to have an omni speaker located where each source was located (relative to the listener). Having two separated omni speakers create a phantom center is not going to generate the same room interactions that a source actually in the center would.

I think I've read and considered the implications of each post in this thread (but not all links, etc). I'm fairly well convinced that a center channel speaker should have dispersion that's equal in the horizontal plane from +90 to - 90 degrees, and have no dispersion behind it, since any reflections from behind it should already be in the mix (either recorded authentically, or placed there by the sound designer). This thread has had little attention paid to vertical dispersion, and whether it should be broad or limited or if it really matters, and if so how. I have thoughts on that from prior experience and research. I'm not sure what dispersion stereo speakers should have ideally, even though that's the primary focus. Based on this thread, I'm also not sure whether when I listen to that center channel, I should have my walls treated or not. I suppose a speaker designer need not concern himself with such questions as wall treatments.

I will suggest the following thought experiment (to all thread participants):

Consider going to your favorite venue, and recording your favorite live performance with a single omni-directional microphone, placed in your preferred location. All the reflections of the venue will be captured with proper levels and delays.
Now consider playing back that recording on a single speaker (your dream speaker), and listening to it in an anechoic chamber.
How do you think you would like the sound?