omnidirectional loudspeakers = best design available

[matt3421]

speaking of omnis, does anyone have the homepod mini?

 

[Blumlein 88]

The instances where I've had customers and colleagues go from three-channel stereo back to two-channel stereo have all involved switching to highly directional main speakers strongly toed-in, such that their axes criss-cross in front of the center sweet spot. Credit to Earl Geddes for this idea, which (somewhat counter-intuirively) results in good soundstaging across a wide listening area.

I've crossed my speakers just in front of the LP for years and years. So that Geddes fellow must be pretty smart.

 

[andreasmaaan]

My understanding is that "ASW" is conveyed primarily by the early sidewall reflections, while "envelopment" is conveyed primarily by the later-onset reflections which arrive from all around. And my understanding is that significant early reflections tend to work against envelopment, which implies a tradeoff relationship between the two. And that has been my experience, but I do not claim my experience to be all-encompassing or derived under controlled blind testing conditions.

My memory of the research is a bit hazy on this question, but I'm going to refresh my memory and see what I can turn up.

FWIW, I haven't tested myself whether such a tradeoff is part of the deal. My personal (uncontrolled) experience is with (reasonably) constant-directivity speakers, toed-in past the listener so that the strongest lateral early relfection is off the opposing sidewall, a la Geddes. I find this produces a nice balance between ASW and LEV, without significantly harming image precision. I also like to treat the front and back walls with broadband absorption FWIW.

 

[andreasmaaan]

Yes the sides cancel out and you have the Mid left. Should be the same thing.

Ok, perhaps I misunderstood you. Mid/side processing should consist of side signals (L-R) and mid signal 0.5*(L+R). As I understood your earlier description ("3 speakers with the center channel made up of a mix of L+R and the level reduced"), side signals consisted of simply L and R.

Do you have a link to this research by any chance?

 

[Newman]

Toole likes upmixed stereo, and I've never heard upmixed stereo that I liked at all. I like mch when the source is. Upmixing no.

Correction: you may not have meant it, but your words above suggest that he likes any old upmixing. He dislikes most stereo upmixers, strongly so. He is very selective about which upmixers do it well. Very, very selective. The only one I have seen him mention in a positive light is Logic7.

Also, I don’t think he is saying “I like it, you may not”, as if it’s just personal taste peculiarities. I think he is saying that the attributes that upmixing brings to stereo are attributes that have near-universal preference.

IMO it is something to pursue and get right, because the benefits are universal.

P.S. so far I am with you, my limited exposure to generic upmixed stereo products (Dolby PL II Movie, Dolby PL II Music, DTS Neo 6 Cinema, DTS Neo 6 Music) has not been enjoyable. Nor has Toole liked them, AFAICT. I look forward to finding a good one.

cheers

 

[Blumlein 88]

Ok, perhaps I misunderstood you. Mid/side processing should consist of side signals (L-R) and mid signal 0.5*(L+R). As I understood your earlier description ("3 speakers with the center channel made up of a mix of L+R and the level reduced"), side signals consisted of simply L and R.

Do you have a link to this research by any chance?

I don't have the link recorded. It is a paper on the web from I think the 1960's. I don't know if I've posted it here, I have posted it over on CA under the username esldude. I'll see if I can find it.

 

[BenB]

The instances where I've had customers and colleagues go from three-channel stereo back to two-channel stereo have all involved switching to highly directional main speakers strongly toed-in, such that their axes criss-cross in front of the center sweet spot. Credit to Earl Geddes for this idea, which (somewhat counter-intuirively) results in good soundstaging across a wide listening area.

As I mentioned earlier, I absorb the contralateral reflection from my left speaker, because my right wall is too close. So the idea of directional speakers allowing for a smaller room is rather suspect to me. I can understand how exaggerating the contralateral reflections (while reducing the ipsilateral ones) for something that's supposed to be centered in the mix is appealing: you still get reflections on both sides, but the are delayed more, and come at a greater angle. However, having a strong contralateral reflection for something that's panned significantly off-center doesn't sound appealing to me. Why should it be that something that's a bit off to my left should echo strongly on my right, but not my left? I find myself similarly distracted (aggravated) when spaced pairs of microphones pick up the same off-center sound when the delay is long enough, and the frequency high enough that the sounds don't correlate at the listening position (as can be the case with way off-center cymbal hits, for example).

 

[Newman]

(writing to Shazb0t)
...why be ragging on omnis for being impossible to actually re-create The Original Performance, when it's not really possible for any speaker?....

Perhaps because the OP opened this thread with, “Omnidirectional loudspeakers produce the most realistic musical soundstage in the home” .... “The superiority of the design is easily heard” .... “Live music and therefore sound propogation happens omnidirectionally, and is how our ear-brain mechanisms have evolved to understand sound” .... “Most loudspeakers beam the sound toward the listener in a totally unnatural way” .... “they actually excite the listening room LESS than conventional speakers” ....

So it’s not about whether they are perfect: it is about whether omni speaker reproduction is ‘natural’, whether live music is omnidirectional so omnidirection speakers are doing it ‘the natural way’. It is OK, IMO, to ‘rag on’ about how those statements are not true. That, I think, is where @Shazb0t is coming from.

 

[Sancus]

Correction: you may not have meant it, but your words above suggest that he likes any old upmixing. He dislikes most stereo upmixers, strongly so. He is very selective about which upmixers do it well. Very, very selective. The only one I have seen him mention in a positive light is Logic7.

He uses Auro3D these days. Which is distinct from Auro2D, I should note. I also think Auro3D is by far the best, however it requires at least 4 height channels.

 

[Blumlein 88]

Ok, perhaps I misunderstood you. Mid/side processing should consist of side signals (L-R) and mid signal 0.5*(L+R). As I understood your earlier description ("3 speakers with the center channel made up of a mix of L+R and the level reduced"), side signals consisted of simply L and R.

Do you have a link to this research by any chance?

Haven't found the one I'm looking for. Did find this interesting one by Steinberg and Snow. Included in a Paul Klipsch monthly newsletter of some sort from 1964. It is the 2nd article in this jumble of articles. It was done in the 1930's.

https://www.aes.org/aeshc/docs/bell.labs/auditoryperspective.pdf

People behind a curtain were walking around a stage while playback of them speaking was done over various combinations of 2 or 3 channel playback. Observers wrote where they heard the sound coming from on a grid. Here is the diagram of the results if you can decipher them.

BTW, I found this using the www.yippy.com search engine which seems to give nice results on technical items vs google. It is an IBM search powered by their Watson AI.

 

[Shazb0t]

Yes, that is why I found your previous comment curious:

It's all an illusion, and why be ragging on omnis for being impossible to actually re-create The Original Performance, when it's not really possible for any speaker?

As Floyd and others have pointed out, the way most music is mic'd, and the way microphones/stereo works, means it's not suited to "accurately reproduce the original live performance." So, depending on our goals, we pick our compromises, or solutions. I found that my omnis, while not in fact reproducing the original sound, produced qualities that *mimicked* the sensation of hearing real instruments, and so to some degree mimicked (one may even say, carefully, "restored") a sense of the original sound. And I had the original sound to actually compare.

I don't see any inconsistency with what I've previously said. I interpret Toole as basically making the same point, albeit more eloquently. I'll counter your take with my own emphasis.

"Which, of course, is quite impossible with only two channels! What we hear is only hints of what might have been, as tweaked by recording and mastering engineers. Nothing approaching the original sound field is captured, stored or reproduced. An active imagination is required, and that very likely is strongly individualistic. The problem is the "system" (stereo), not the loudspeakers. This does not mean that music cannot be extremely pleasurable, but the expanded "circle of confusion", if reality is the goal, is not a circle at all. It is a dead end, so long as we stick with two channels. Let the flames begin . . ."

My point is that Omni speakers can't take music recorded and mastered for conventional stereo reproduction and recreate or "restore" it accurately to the original live performance. No speakers can, including conventional forward firing loudspeakers. People who state that this magic is somehow possible either don't understand what they're talking about or are drinking their own cool aid. I'm not claiming that conventional forward firing loudspeakers recreate a live performance in my listening room, but as far as I can tell the OP and you are making the claim that Omnidirectional speakers can! You can believe what you want but it should be clarified that the claim that Omni can take a stereo recording and recreate an accurate live performance like it's happening in your listening room is false. It is no more true than making the claim that stereo through conventional speakers is going to recreate a live performance.

Alternatively, the benefit of conventional forward firing loudspeakers is that you get to listen to the music through the same type of setup that it was mastered and approved on by the artist who created it. Being that most music is made in a studio this way you have a much higher chance of hearing it as it was intended to be heard by the artist who created and released it. Throwing Omni into that chain adds permanent embellishment to the entire system. You may find that embellishment appealing, but it's not any more accurate than the conventional system. In fact, it is logically less accurate to the artists intent. If you have a valid counterargument to this point then we can continue this back and forth. If you don't then I think it's best to just let it go. I don't see either of us changing our minds and we've both said our peace.

 

[krabapple]

Where I do disagree somewhat is with the juxtaposition with dr. Toole as the only alternative, kind of. You didn't say that exactly (please don't take this the wrong way, I'm simplifying), but there is some tendency among people to lift up Toole's opinions as the final word. One of the merits of Toole's book is that he (mostly) presents a broad overview of the state of audio research, not just his own studies, so it's possible to assess his claims. He's often more open to diverging opinions than many of his followers, I think... (as far as I know Toole never compared stereo and multichannel himself, for example - his views here are based on the studies of others).

He has certainly used both stereo and multichannel in his own listening setups over the years, so why do you think he would not have formed a comparison-based opinion? And of course he can turn off an upmixer any time he wants.

 

[AdamG]

Very interesting conversation. I’m going to ask the stupid question, mostly cause I don’t like to assume something. This Subject and subsequent conversation applies to some degree to Electrostatic Speakers as well, correct?

 

[Blumlein 88]

Very interesting conversation. I’m going to ask the stupid question, mostly cause I don’t like to assume something. This Subject and subsequent conversation applies to some degree to Electrostatic Speakers as well, correct?

Well, no.

ESLs have the same sound from the front and back except the rear wave is 180 degrees out of phase with the front. With nulls of almost no sound to the right and left of the speaker panel.

If I wanted to be some kind of crazy purist, I'd say all recordings done with a ribbon microphone pair should be played back over dipolar ESLs.

All recordings done with a spaced pair of omnis should be played back over only MBLs.

All recordings done with cardioid mics should be played back over monkey coffins.

 

[andreasmaaan]

Haven't found the one I'm looking for. Did find this interesting one by Steinberg and Snow. Included in a Paul Klipsch monthly newsletter of some sort from 1964. It is the 2nd article in this jumble of articles. It was done in the 1930's.

https://www.aes.org/aeshc/docs/bell.labs/auditoryperspective.pdf

People behind a curtain were walking around a stage while playback of them speaking was done over various combinations of 2 or 3 channel playback. Observers wrote where they heard the sound coming from on a grid. Here is the diagram of the results if you can decipher them.

Thanks Perhaps I'm misinterpreting the diagrams, but it seems to me that 2-channel stereo vs 3-channel gave similar levels of perceived depth overall, with 3-channel giving a slightly narrower but no less realistic perceived depth to the mid images, and a more realistic perception of depth to the side images?

Also, I'm not sure this is quite relevant to the discussion about M/S processed 3-channel stereo, because in this study it seems that the signals were simply added for the centre channel, with no side processing for the sides (which explains why the side images were dragged to the centre)... But I know it's not the study you were originally referring to!

BTW, I found this using the www.yippy.com search engine which seems to give nice results on technical items vs google. It is an IBM search powered by their Watson AI.

GTK, thanks

 

[AdamG]

Monkey Coffins? Not sure but is this in reference to your regular box speaker?

 

[Blumlein 88]

Monkey Coffins? Not sure but is this in reference to your regular box speaker?

Yes. Cones and domes if you prefer. Box speakers.

 

[richard12511]

Very interesting conversation. I’m going to ask the stupid question, mostly cause I don’t like to assume something. This Subject and subsequent conversation applies to some degree to Electrostatic Speakers as well, correct?

I would say no. At least with the electrostats I've heard(ML), they have more in common with a narrow dispersion horn speaker than they do an omni speaker. The electrostats I've heard throw a super clear and precise, yet super unstable image, which is the same as what my JTRs do, and it's the exact opposite of what a good omni will give you.

I get why you asked that, though. They do seem to be getting somewhat lumped together here, and I'm not sure I totally understand why. I think @Duke has actually made some really great points re: min/maxing early vs late arriving reflections, but (at least based on what I've heard) his points are good arguments in favor of dipoles, not omnis.

BTW, I'm somewhat shopping for a decent omni for my garage setup, but nothing super expensive. The Revel M105s are oddly not wide enough dispersion for the amount of pacing around I do while working out. Any measurements out there of reasonably priced omnis? I was looking at Ohm, but it seems they're not well regarded here. I've heard and enjoyed the giant $200,000 MBLs, but no way can I afford even 1/10th of that for a secondary system. Morrison audio has been brought up a few times, but they're still too expensive(from what I've seen). Maybe if I can find a really good used price, but still, I can't find good measurements, and I'm super hesitant to buy speakers sans measurements these days.

 

[AdamG]

I would say no. At least with the electrostats I've heard(ML), they have more in common with a narrow dispersion horn speaker than they do an omni speaker. The electrostats I've heard throw a super clear and precise, yet super unstable image, which is the same as what my JTRs do, and it's the exact opposite of what a good omni will give you.

I get why you asked that, though. They do seem to be getting somewhat lumped together here, and I'm not sure I totally understand why. I think @Duke has actually made some really great points re: min/maxing early vs late arriving reflections, but (at least based on what I've heard) his points are good arguments in favor of dipoles, not omnis.

BTW, I'm somewhat shopping for a decent omni for my garage setup, but nothing super expensive. The Revel M105s are oddly not wide enough dispersion for the amount of pacing around I do while working out. Any measurements out there of reasonably priced omnis? I was looking at Ohm, but it seems they're not well regarded here. I've heard and enjoyed the giant $200,000 MBLs, but no way can I afford even 1/10th of that for a secondary system. Morrison audio has been brought up a few times, but they're still too expensive(from what I've seen). Maybe if I can find a really good used price, but still, I can't find good measurements, and I'm super hesitant to buy speakers sans measurements these days.

‘Hi Richard,

Thank you for the clarification and expounding what I have read in this thread previously. Appreciate the effort. About those JTR’s. Jealous. Almost went with an all JTR system, I have dual 2400ulf’s but our room is a multipurpose space and when I showed the Admiral the JTR210/212’s I was considering I was confined and threatened with Bread & Water. So, the ESL-X’s were my next choice. Still regret not going all JTR. Maybe some day.

 

[Duke]

As I mentioned earlier, I absorb the contralateral reflection from my left speaker, because my right wall is too close. So the idea of directional speakers allowing for a smaller room is rather suspect to me.

I suspect the asymmetry of your room is your issue, not contralateral reflections in general. I've yet to encounter an issue with them, but I've yet to try it in a room like yours. And it sounds to me like you've found an effective solution.

This Subject and subsequent conversation applies to some degree to Electrostatic Speakers as well, correct?

The short answer is, I think so. And as you can already tell, I have a longer answer in mind.

You see, imo yours is an excellent question because its implications reach far beyond electrostatics: Just how widely applicable is this subject and the subsequent conversation?

I think there is potentially significant common ground among omnis, dipoles, bipoles, other polydirectionals, cardioids, constant-directivity narrow-pattern monopoles, well-behaved wide-pattern monopoles, Live-End/Dead-End, Reflection Free Zone, multichannel upmixing, and doubtless other approaches.

Their conceptual common ground, subject of course to appropriate set-up, is imo articulated well by oivavoi:

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. [emphasis Duke's]

Imo what all of these different approaches have in common is the pursuit of “much late indirect sound which is similar to the direct sound, but the direct sound still dominates the perception and creates good stereo images.”