omnidirectional loudspeakers = best design available

[MattHooper]

"Here we are", indeed. Your landing place is what happens when internal self-logic is the guiding force, and not data.

There’s another place that some people end up, when they believe they’re being guided strictly by data (or their own interpretation of it) without sufficient experience.

Sometimes personal experience can be misleading - see audiophiles imagining they hear differences between AC cables and the like. But not everything audiophiles hear is imaginary, and sometimes we really can learn things from personal experience with certain types of gear.

Someone may have an admirable zeal for collecting research citations. But there’s always the issue of interpretation, and sometimes a deficit in experience shows up in the interpretations.

Some of us - Me, Floyd Toole, and some others - have had extensive experience dialling in high quality Omnis to our purposes. And we have found, even within the context of experience with other excellent direct radiating speakers or excellent surround systems - that Omnis have produced some uniquely compelling characteristics. Again… all in the context of suiting personal preference or particular goals, that Omnis are suitable for achieving, even if imperfectly.

Which is why we don’t make the mistake of warning people away from Omnis, as if they are the audio equivalent of a Pied Piper leading somebody away from some other proper form of audio ecstasy.

 

[MattHooper]

I think it’s obvious that Omni speakers do not perfectly replicate the radiation pattern of real voices and instruments. There’s going to be variations in radiation patterns given different instruments, and so the Omni “ one size fits all” radiation pattern of all frequencies being Omni is clearly going to be imperfect.

But a lack of perfection reproduction in this way shouldn’t blind us to what an Omni might be “ doing right” in perhaps a more generalized/imperfect way with some respects of the sound. The idea that an Omni cannot have any real relationship with a “more natural sounding presentation” would seem a bridge too far. After all, as I pointed out earlier, Dr Toole himself talked about using Omni in his own room to better mimic certain spatial aspects of real orchestral sound.

On a personal level, whatever may be cited as “wrong” about the Omni presentation, I still found they produced for me the most realistic impression of real instruments in real acoustic space that I experienced in my home. And that held up when I did live versus reproduced sound comparisons.
(Second best were my Thiel 3.7s).

 

[MattHooper]

If we are speaking about the major tradeoff between enveloping reverb/ambience vs. localization stability/precision, I would say that the advantage of achieving the former to the fullest, inevitably means a compromise on the latter aspect.

Maybe I am biased here, as I pay a lot of attention to localization (which basically every recording engineer experienced in classical recordings would, as positioning main microphones and panning spot microphones for matching localization and coherent imaging, is one of the things to do the most during mixdown). So for me personally, omnis have never been an option.

I don’t think we’re too far off in our goals perhaps.

At the forefront of what I care about in reproduced sound is:

1. Timbral authenticity/beauty (first thing I notice)

2. Sonic density and palpability. I’m always somewhat fighting against the diaphanous quality of stereo phantom images. There’s always a more ghostly, phasey incorporeal quality versus the real thing. Therefore any systems that bring more density and palpability to the sound catch my ear. And often (but not always in my experience) a speaker that brings imaging focus and precision helps with this. It’s one reason why I’ve been such a long time fan of Thiel speakers because this is what I perceive that they really bring to the party - an amazing assuredness in imaging and precision, with a particular Sonic density to the Sonic images as a result. So I value that highly as well.
(I’d also point out that, in my experience, a sense of sonic density doesn’t always have to come from sheer image focus. Sometimes certain frequency profiles or other forms of distortion may help. For instance a bit of emphasis - say between 300-400 or 150-250Hz depending - might give a male voice more chest like resonance and solidity. And it’s been my impression that certain tube amp and vinyl distortions can add and oppression of more Sonic density, and palpability as well in some situations).

3. Spatial properties. The sense of the speakers disappearing as a source of the sound. The sense of “ real sounds occurring in real acoustic space” etc.

As you indicate… it’s a balancing act trying to get all these things together, especially between the special qualities and the focus and density of imaging. Eg the type of trade-off you’re gonna get with a typical speaker in a typical room, where toeing in and toeing out the speakers well often yield to trade-offs between image focus and more relaxed spatial difficulties.

So I’m always trying to balance those.

I’d say that for me, my bigger Thiel 3.7 speakers came the closest to my platonic ideal in that regard. They managed to both cast monstrously wide and deep soundstages when the recording permitted, yet with amazing density and specificity of imaging.

The MBLs edged the Thiels out in sheer “ disappearing act” and convincing imaging and spatial qualities, though with less image focus. (Though still for my taste - plenty precise enough to still be satisfying and believable).

More recently I have got the best combination of soundstaging and sonic density from my slightly smaller Thiel 2.7 speakers after I discovered the effects of adding a curved diffuser just behind and in between the loudspeakers. The 2.7s were already among the most sonically dense imaging speakers, I know of, but adding that diffuser somehow took it to another level, where the images became even more solid and dense. It can feel uncanny sometimes.
I don’t have a picture using it with my Thiels, but I also use it with my Joseph speaker speakers which can use a little help sometimes in the sonic density department (they focus images really precisely, but still don’t have the palpable solidity of the Thiels, but they come a lot closer with the addition of this diffuser that I simply put on my home theatre centre channel between my two channel speakers)

I wish I’d tried that back when I had the Omnis. It’s possible it would’ve yielded some really cool results.

 

[MarkS]

Maybe I am biased here, as I pay a lot of attention to localization (which basically every recording engineer experienced in classical recordings would, as positioning main microphones and panning spot microphones for matching localization and coherent imaging, is one of the things to do the most during mixdown).

My all-time favorite classical recordings were done by Telarc with (as I understand it) no spot miking at all.

I attend a lot of live classical performances, usually in a mid-hall seat, and "coherent imaging" is not something I ever hear.

 

[Mnyb]

Was not OP shilling Morrison speakers from the get go ? Concept is very limited imo ? probably a fine product if you specifically want omni.

 

[ShadowFiend]

My all-time favorite classical recordings were done by Telarc with (as I understand it) no spot miking at all.

I attend a lot of live classical performances, usually in a mid-hall seat, and "coherent imaging" is not something I ever hear.

I agree with you, and when listening to the symphony even at the second row seat of the big concert hall, the extreme „coherent Imaging“ is also not existed. I only experienced that in the small chamber music concert when sitting close to musicians.

 

[Arindal]

you really haven't read Toole's books, have you?

I actually did, back in the days. But you seemingly have not read the standards like Zwicker, Zollner, Fastl, Dickreiter, Sengpiel, Brüderlin, as well as the more practical books on instruments´ acoustics and microphonization, haven't you? Highly recommended!

try harder to be fact-based.

Could you pls link to the so-called ´facts´ stating that a human voice or clarinet sounds as desired with the directivity pattern of a trumpet? I am really very curios to read about it! It is such an absurd claim that even people who sympathize with all the ´Harman curve´ stuff, should laugh about themselves.

you support my conclusion that the OP's claim of the critical superiority of the 'natural' dispersion of omnis, is debunked, but you have your own reason for landing there.

If you look solely at ´natural dispersion´ in the sense of tonally balanced reflections and directivity, nothing is debunked. Despite my personal resentments, I would rather say that supporters of omnis have a point here, and the theory that loudspeaker directivity pattern should be resembling natural instruments´ patterns, is ill-conceived from the very basic layer of how stereophony works and how different the most important instruments behave, and therefore is completely debunked.

My reason for not liking omnis, to a great extent has to do with phantom localization quality and perceived proximity. Two aspects which are outright denied by Dr. Toole and Amir to play a role in loudspeaker quality evaluation, or by their own ´scientific standards´, taken at face value, are proven to speak in favor of omnis. If you accept my arguments that localization should be as precise, stable and as proximate as in the studio control room, you at the same time dismiss everything that Toole/Olive/Amir/Harman have been stating about reflections and perceived imaging.

So, which pill would you choose?

What theory?

Any theory defining sound quality as reproducing what is in the recording and coming as close as possible to what has been heard in the studio control room. If you want to know more about the ´why´, I recommend to read Linkwitz´ papers on the topic of balanced indirect soundfield.

this is what's happening here, isn't it? You have a gut-based feeling, boosted with internal logic, and no data.

What tells you I do not have data? Take the simplest spinorama calculations of reflection window tonality as data or the in-room-response or even better the diffuse field response. Increasing, oder very uneven directivity index inevitably leads to colorated indirect sound. The data is there, we can discuss its implication on reproduction quality.

 

[Arindal]

My all-time favorite classical recordings were done by Telarc with (as I understand it) no spot miking at all.

Could you name an example? Telarc has a track record of pretty different sounding recordings, and while I do very much like some of these, I find it unlikely that good recordings involving orchestra or choir, have been done without any spot microphones. There have been such attempts, for example by Denon (One Point), BIS and Chesky, but they exhibit the shortcomings of this technology pretty obviously.

attend a lot of live classical performances, usually in a mid-hall seat, and "coherent imaging" is not something I ever hear.

Such concert venues indeed exist in the sense of mid-hall seats being outside the critical listening distance already (oftentimes these are box-shaped concert halls with dominant side-wall and ceiling reflections, such as Vienna Musikverein, Tonhalle Zurich, Berlin Konzerthaus, Munich Herkules). I would personally recommend seats in the first 8-10 rows in this case, as this is the perspective most of recording engineers would choose for their imaging.

when listening to the symphony even at the second row seat of the big concert hall, the extreme „coherent Imaging“ is also not existed.

That is interesting. Did you attend a performance of an oratorio or symphony with soloist singers in this one? It should usually reveal localization capabilities.

 

[ElJaimito]

The most important aspect of home audio reproduction, is the role of the loudspeaker. Omnidirectional loudspeakers produce the most realistic musical soundstage in the home; however they remain the least understood by the public and audiophools alike. The superiority of the design is easily heard when in person, and when measured, particularly in the off-axis domains both vertically and horizontally. Live music and therefore sound propogation happens omnidirectionally, and is how our ear-brain mechanisms have evolved to understand sound. 98% of loudspeakers are designed incorrectly; yes you read that right and it's easily verifiable w/ measurements. Most loudspeakers beam the sound toward the listener in a totally unnatural way, and suffer what are called 'lobing effects' and again, are easily measured particularly when you start to move off-axis. (marketing department of companies don't measure nor publicize these measurements once out of the sweet spot, because they are horrible). These concepts have been substantially explored by the late Sigfried Linkwitz of Linkwitz Labs; I believe all his research and papers are available at the website. Further explanation is available at the website of Morrison Audio loudspeakers, highly recommended. It is important to note, that there is major distinction between polydirectional speakers, and omnidirectional.

Makers of omnidirectional loudspeakers include:

Ohm Acoustics
German Physiks
MBL
Mirage (out of business; still available used)
Linkwitz Labs (LX Mini is a hybrid omni)
Duevel
Morrison Audio

I would encourage anyone who is serious about music, and wants the most realistic soundstage in their home, to pursue omnidirectional loudspeakers. Contrary to audiphool misunderstanding, they actually excite the listening room LESS than conventional speakers, and require LESS or no special room treatments.

Rules for making a great omni:

-design should be 2-way. Single driver is inadequate; 3-way is unnecessarily complicated
-woofer driver should face UP, with lots of room behind it to reduce or eliminate back wave from radiating back out the cone
-tweeter should also be facing UP
-both woofer and tweeter should be place immediately together, and with dispersion caps or guides to disperse the outgoing sound both vertically and horizontally
-cabinet should be totally inert, as measured by accelerometer
-speaker should be able to be driven using either a passive or active crossover
-inputs should be Neutrik Speakons; Benchmark Media has measured conclusively the lowered distortion of Speakons compared to binding posts (spades or bananas)
-listening height of drivers should be at listener's seated ear level OR LOWER

This considered, the 2 best omni designs, and therefore the 2 best loudspeaker designs in the world right now, are from Duevel in Germany, and Morrison Audio in Canada. All others on the list are "honorable mention".

I'll have to take issue with your first (and unsubstantiated) declaration: omnidirectional speakers I assert give the least high fidelity reproduction of any type, in any and all acoustics. I don't think I agree with any of your other assertions either. Best.

 

[ShadowFiend]

It has been interesting to follow the trajectory of this thread.

As hinted in the title, it started with a bold proclamation of the clear and indisputable superiority of the omnidirectional speaker principle for sound reproduction.

• They produce the most realistic soundstage
• Their superiority is easily audible
• …and easily seen in the measurements
• They are naturally aligned with our ear-brain mechanism
• All other loudspeakers are designed incorrectly
• …and easily verifiable with measurements
• All other loudspeakers are totally unnatural
• Anyone who is serious about music should adopt them
• The 2 best omni speakers are automatically the 2 best loudspeakers in the world
• So far superior to a standard speaker, it is not even close (post 3)
• All forward firing speakers are inherently flawed and totally outdated (post 138)
• If you want to progress you have no option but to go omni

Slowly but surely, a science-based discussion emerged in which every important aspect of the opening declaration was debunked. Inherent superiority became inherent inferiority.

It was not plain sailing from A to B, though, because, just like any audio thread to discuss an unusual technology, it attracts current owners, past owners, and excited fan type observers, who tend to search the internet for any and all discussion of their favourite toy. Not just on Day 1 of the thread, but newcomers find it again and again, for years. Understandably, they are reluctant to concede that the ‘obvious’ advantages may be disadvantages when put to the Bunsen burner. But I think the thread got there in the end.

And the most recent revival of the thread has settled into a general chat line for omni speaker talk, unrelated to the topic title. All good.

But since the current discussion is about whether to ‘manage’ the way-off-axis output (and hence reflections), or to ‘free’ them, I reckon it’s worth a quick reminder of where the science-based discussion landed.







cheers

Another ranting and trying to prove superiority without evidence.

1. Firstly, in diametrical opposition to the claims of proponents, the dispersion of an omni is completely unlike the dominant musical instruments or the human voice. Conventional speakers are a much closer approximation.

This is a weak argument. here is why:
1. If we treated music instrument distinctively, while dispersion of musical instruments and human voice is not omni, its is varied greatly between instruments. So any speaker, not just omni, is only right with a a certain instruments/voice and completely wrong with another.
And closer approximation is not equal to correct.

Even Dr Toole noted in 4th edition of his book "High frequencies from violins radiate vertically away from the top plate of the instrument, while other frequencies radiate
in other directional patterns. Those from a trumpet project strongly outward from the bell of the instrument. Other instruments may radiate almost omnidirectionally, or with a pattern of a dipole radiator (figure eight) over different frequency ranges."

Detailed about directivity of instruments. Source: "Directivity of musical instruments" - Aalto University

2. On recordings, especially in orchestra works, when the full orchestra or big parts of orchestra is playing, so the directivity are much more complicated than each instruments/voice. Not to mention the reverb part of sound recordings.

Secondly, psychoacoustic research into preferred vs non-preferred room reflections has shown that the reflected content that the listener experiences from an omni, is of the wrong amplitude, wrong timing, and from the wrong directions. And all of those wrongs can be righted by using a conventional multichannel setup.

1. What experiment/research support your claim?

The paper "Effects of loudspeaker directivity on perceived sound quality - a review of existing studies" by William Evans , Jakob Dyreby , Søren Bech, Slawomir Zielinski, and Francis Rumsey on AES Convention 126 in 2009 summarizes many research/experiment about the directivity preferences on speaker, and no research involved omnidirectional speakers, not to mention a good omnidirectional speaker like big MBL. So what is the backup of your claim? Are you hallucinate to get this fact.

2. An multichannel setup is better than 2 channel setup, but this is only on "real" multichannel recordings. If your source is mono/stereo music, which counts for more than 99% of music in the world, you need an "upmixer", right? So another question is, which research provides evidence that upmixed stereo music on multichannel setup is superior to reflection-enhanced stereo music setup (dipole, omnidirectional) on blind testing? For what I know, there is none.

Even the proponent of multichannel system like Dr Toole provides a balanced view on the chapter 8.6.1 "Upmixing, Downmixing and Rendering" of his book.

I think the above landing points are worth reiterating, because I am pretty sure that most people who went to omni speakers did so on the understanding that they were pursuing ultimate sound reproduction, ie they have very high standards for desired sound quality and are keen enough to pursue it, and omni was being touted as the ultimate way to approach it. To those people, learning that the core principles of omni speakers are quite problematic, inherently so, and pursuing them can do little other than lead them away from ultimate sound reproduction, should be an enlightenment that they welcome. And worth reiterating from time to time.

On the contrary, all of people go with omni directional speaker I know do not try to get dogmatic view of "ultimate sound reproduction". They go with omni directional speaker because for them, omni speakers reproduce the experience they have with their favourite music in concert hall better than all the conventional box speaker they tried. That is it, so simple.

 

[ShadowFiend]

That is interesting. Did you attend a performance of an oratorio or symphony with soloist singers in this one? It should usually reveal localization capabilities.

Yes, I attend Beethoven 9 and choral music like Mozart Requiem several times. If you talks about localization capabilities like the ability to identify position of baritone/Bass, tenor, contralto/mezzo, soprano then of course, it is possible even in midhall seat and omnidirectional speaker can definitely do it. But the localization to differentiate between two wind players is not easy, especially when they are sitting close to each others.

And what annoys me that on many recordings, when violin playing, which contains of more than 20 instruments located in wide area, it seems that they all comes from one small point in the soundstage, especially when listening on studio monitor. And Omni speaker correct that annoying very well.

 

[Arindal]

But the localization to differentiate between two wind players is not easy, especially when they are sitting close to each others.

That is to be expected, particularly with instruments being further away from the listener, tending towards an omnidirectional pattern and showing a rather non-transient, more constant tone emanation over time. Our ability to localize, relies vastly on harmonics and transients, for example the ´attack´ of percussions and brass, as well as sibilants of the human voice.

what annoys me that on many recordings, when violin playing, which contains of more than 20 instruments located in wide area, it seems that they all comes from one small point in the soundstage

Fully understand that you find this annoying, but my observation would be that this has become a rather rare type of aesthetics in recent decades of recording classical music. I mainly know that from minimalistic recordings trying to expand the stereo base pushing violins and celli to the extreme flanks (early Deccas and RCA Victor come to mind), or by some conductors who specifically liked the ´conductor´s perspective´, like some Karajan late recordings for DGG and Celibidache for Sony.

One of the rare examples which are among my favorite recordings (admittingly from 1954):

Could you name a more recent example please?

 

[ShadowFiend]

Recent recordings have much less of that, but I still remember many recordings of HIP performances on Harmonia Mundi around 1990-2000 have this kinds of deficiencies.

 

[MattHooper]

Secondly, psychoacoustic research into preferred vs non-preferred room reflections has shown that the reflected content that the listener experiences from an omni, is of the wrong amplitude, wrong timing, and from the wrong directions.

1. What experiment/research support your claim?

Indeed. It does seem like a rather sweeping claim.

Consider that TOOLE WROTE:

“As I describe in the 3rd edition - Section 7.4.6 - I purchased a pair of nearly omnidirectional Mirage M1s for my large, somewhat live, classical "concert hall" - the largest I could afford at the time . They did well in small room double-blind tests at the NRCC,”

If Omni radiation pattern is “ wrong wrong wrong” and non-preferred, why did the Mirage speakers do so well in double blind comparisons in a small room?

Not to mention why would Toole himself choose them as his own loudspeakers for a long time and enjoy the presentation?

(Hint; because Toole has a more nuanced understanding of the data, along with personal experience with a good omni , and so hasn’t adopted an irrational anti-Omni vendetta).

2. An multichannel setup is better than 2 channel setup, but this is only on "real" multichannel recordings. If your source is mono/stereo music, which counts for more than 99% of music in the world, you need an "upmixer", right? So another question is, which research provides evidence that upmixed stereo music on multichannel setup is superior to reflection-enhanced stereo music setup (dipole, omnidirectional) on blind testing? For what I know, there is none.

As I mentioned before: I have a very good surround system - my room having been renovated for a surround home theatre set up employing a professional acoustician who designed a number of our expensive POST PRODUCTION mixing studios as well as high-end home theatres. I’ve been told by some other Home theatre contractors that mine was one of the best consumer surround set ups they had experienced in terms of rich sound and envelopment.

But I also had the MBL omnis to play with for about 10 years, in the same room.

And when I tried using the MBLs as the L/R speakers for my surround set up, the effect was just fantastic. There was a very distinct jump in the sense of realism in all sorts of content. No sense of the sound coming from loudspeakers at all. And the spread of many background and atmosphere sounds around the projection screen became intensely realistic, like the air and atmosphere of that scene simply merged into the room.

It really had me thinking about what it would be like to replace all of the Home theatre loudspeakers with the MBLs.

This is one reason why I was so interested to read a report from Michael Fremer who got to live with a fully omnidirectional sound system from MBL . The system used larger MBLs for L/R but used the same 121 MBL model I owned for all the surround speakers.

I personally have not been able to find anybody reporting on the experience of a full Omni surround system except this report.
And given my own experience with the MBLs as part of my surround system, I’m not surprised at all by the type of experience MF describes.

 

[MattHooper]

I admit, I’m always puzzled when I see people say that live orchestral music has no imaging.

I used to go to the symphony regularly, and since I was fascinated by live versus reproduce sound, I would always close my eyes and listen - taking the character of the sonic experience.

I always heard imaging.

Of course it would vary, depending on my seating position. If I was further back in the hall then of course, individual players and sections would blend into one section, but certainly the sections were still in specific locations relative to one another, and soloists also would come from certain locations.

But I mostly favoured close up seating to the symphony because I liked the more vivid instrumental timber and spread of the sound.
And certainly there the localization of different sections and individual instruments and soloists was even more distinct.

 

[ShadowFiend]

I think no imaging is the relative term compare to the "pin point" imaging that people experience from many recordings. For example, when listen to various classical music recordings from 1970-1990 on my KH120 in nearfield, I can easily pin point in the 2D-sound field the position of each wind, brass players even when they sit close to each other or the position of viola, cello, violin section in point. This kind of imaging is IMHO a product of mixing and unlike the experience I have in concert. But many people are fonds with that and for them omni directional speaker is no imaging.

 

[MarkS]

Could you name an example? Telarc has a track record of pretty different sounding recordings

Stravinsky: The Firebird

Stravinsky: The Firebird. Telarc: CD80039. Buy CD online. Atlanta Symphony Orchestra, Robert Shaw

www.prestomusic.com

Recorded digitally in 1978

 

[MarkS]

If you accept my arguments that localization should be as precise, stable and as proximate as in the studio control room

I want the sound to be as close as possible to what I would hear in the audience (at some seat in some hall) at a live performance of the same material. Is that the same as what's heard (over speakers?) in the studio control room?

 

[Emilio75]

I’d be really happy to hear such speakers. Anything leading to more natural sound is welcome. If someone knows places in Paris, France, for this, let me know !

 

[MarkS]

I think no imaging is the relative term compare to the "pin point" imaging that people experience from many recordings. For example, when listen to various classical music recordings from 1970-1990 on my KH120 in nearfield, I can easily pin point in the 2D-sound field the position of each wind, brass players even when they sit close to each other or the position of viola, cello, violin section in point. This kind of imaging is IMHO a product of mixing and unlike the experience I have in concert. But many people are fonds with that and for them omni directional speaker is no imaging.

Yes, this overprecise imaging is my issue with a lot of recordings. Recently I was trying out different recordings of Beethoven's 9th. (And as an aside, it's so great to live in the world of streaming where I don't have to buy a bunch of CDs in order to do this!) Many of them had a good (to me) perspective on the orchestral sound, but then the soloists show up in the last movement, and suddenly they're 5 feet in front of me. Not remotely like what I would hear in any actual hall.