omnidirectional loudspeakers = best design available

[Duke]

On the bit I made bold above, it might be worth mentioning that omnis create maximum playback of the sound of your room, so the spaciousness they create is the sense of the space of your room. If you want that in extremis, then they are a great choice!

I agree with this.

Omnis give you a LOT of early reflections, which in turn give your ears a real good "picture" of your playback room's dimensions. Omnis can do a very enjoyable "they are here" presentation, but unless the room is unusually large and the speakers are positioned well away from the walls, they don't generally do a credible "you are there" presentation.

But if we want a sense of the space of the performance venue, then we don't want that swamped by extreme playback of your room, and multichannel playback using speakers with prominent direct sound is a better choice. Backed up by good recording technique. [emphasis Duke's]

Well said.

In order for the sense of space of the performance venue to dominate over the playback room's "small room signature", we need to minimize those reflections which most strongly convey "small room signature" while encouraging in particular those reflections which most effectively convey the ambience of the performance venue. The earliest reflections are the ones which most strongly convey "small room signature", so we want to minimize those. And my understanding is that the reverberant tails on the recording are what most strongly convey the recording's ambience information. And in turn it is the later-arriving in-room reflections which are the most effective carriers of the reverberant tails on the recording, delivering them to the ears from all around, without the detrimental small-room cues inherent in the early reflections.

Something acousticians often do is, minimize the undesirable early reflections, while still presenting plenty of desirable later-arriving reflections to the listener. This approach can combine excellent clarity with the sense of space on the recording, such that with a good recording we can enjoy that elusive "you are there" presentation, even in two-channel.

Now getting back to loudspeaker design, there is at least one topology which lends itself to this "minimize the early reflections, promote the late ones" approach, given proper set-up: Dipole speakers have minimal sidewall interaction, and if they are positioned far enough out into the room, their backwave energy arrives late enough that it does not contribute a strong "small room signature" but it DOES increase the amount of spectrally-correct energy arriving as later reflections and acting as carriers of the reverberation tails on the recordings. And imo dipoles are not the only type of speakers which can do this.

I know that those few dipole loudspeakers whose data we have seen have not done well in Harman's tests, and to the best of my knowledge they have not released any indication of having tested other multidirectional (or omnidirectional) designs. But if the concept of "minimize the early reflections, promote the late ones" has merit, then loudspeakers topologies which facilitate doing just that might also have merit.

 

[tuga]

Is the music you listen to produced on such speakers? No.

Why is that important for the listening enjoyment of the end user?

 

[tuga]

I owned MBL omnis for years and I recorded my own acoustic guitar, voices of my family, my sons practicing sax and trombone etc.

The omnis did indeed "restore" or at least "produce" the sound of the instruments better than any other speaker design I've owned. While other speakers could produce large soundstages with precise image placement, it seems the microphones/placement generally used for recordings weren't so great at capturing the dimensionality of those objects in space, nor is the mostly forward directed sound from typical speakers, so there is a bit of a sense of images sort of "plastered on to" the soundstage, as if nothing exists *behind* them, losing a sense of realistic dimensionality.
Most directional conventional speakers certainly can sound great and very dimensional, but the nuances I'm mentioning tend to become more obvious when you can compare the two designs, as I did (I've always had multiple speakers on hand that I switch in and out of the system).

So for instance when I'd play the recording of my acoustic guitar on the forward radiating speakers, it could be tremendously clear and vivid and somewhat dimensional. But there was always this cue that it was a recording. On the Omnis, the clarity and timbral realism of the guitar was beautifully reproduced, but with the additional omni reflections, there was then a sense of full dimensionality, of there being a "behind and around" to the guitar as a real one radiates to some degree off all the walls, not just funneled forward. The sensation of hearing a real guitar being played, one I'm very familiar with, was simply more realistic. One can talk about what signal the microphone picked up and thus if the speaker is producing the sound "as the microphone heard it." But the omni produced the sound of the guitar "like the actual guitar in front of that microphone sounded live." So...depends on what exactly one thinks of as "accuracy," what one is going for.

The same went for the other instruments too. And as I've mentioned before, no other speaker design has given a better "sounds real from outside the room" effect either. The recorded sound of my son's sax coming through the omnis, when heard from outside the room, was just uncanny in it's realism. And I fooled a few people here and there in to thinking they were hearing my son practicing in that room without looking in because it was so fun to do that

So I know there have been endless debates about "how real instruments/voices radiate in a room." But actually living with omnis, and testing these things to some degree, leaves me with the impression that, even if neither omnis nor direct radiators get it perfect, the omnis are energizing a room in a way that more closely mimics live acoustic sources.

To get a realistic impression of an instrument playing in your room (reproduce the instrument radiation) you'd need a multi-channel recording made anechoically inside a spherical array of mics and a spherical driver-array speaker with equal amount of channels:

Analysis and Synthesis of Sound-Radiation with Spherical Arrays by Franz Zotter
https://iem.kug.ac.at/en/projects/w...of-sound-radiation-with-spherical-arrays.html
https://iem.kug.ac.at/fileadmin/media/iem/projects/2010/zotter.pdf

Spherical Arrays for Sound-Radiation Analysis and Synthesis by Hannes Pomberger, Franz Zotter
http://dafx10.iem.at/proceedings/papers/ZotterPomberger_DAFx10_Tutorial1.pdf

Perhaps two-channels and a pair of omnis are the next best thing. I owned some weird single driver speakers similar in shape to the Shahinian Compass and they did sound more convincing with solo guitar, violin or cello than conventional boxes and horns.

But I agree with others that omnis have a negative impact on the reconstruction of the original space with recordings where ambience cues have been capture (probably unless the room is very large and the direct/reflected sound ration is high).

 

[Jim Matthews]

I heard a convincing playback from Shahinian Obelisk omnis back in the 1990s. They had a muddled bass response (no subs, pre-DSP) and were power hungry. I was there to lend my modified Dynaco 416.

In a large foyer, with a brick wall behind them and plaster walls flanking us they convincingly reproduced small ensembles and single mic recordings.

They were not particularly coherent with multi-track or multiple mic recordings.

Then, as now, I think impulse response is critical to a successful loudspeaker design: I can forgive some tonal deficits and EQ uneven frequency response but if a speaker smears data in the time domain I won't enjoy it.

 

[MattHooper]

Only "real" omnis I've ever heard are the giant MBLs. My impressions were unfortunately almost exactly opposite of yours. I thought they sounded totally unnatural(and not like the real thing), but at the same time intoxicating and pleasurable in a weird way, as it was like being surrounded in the music. My brain found it totally weird that it was coming from 2 speakers in front of me. Totally unnatural sounding, but at the same time really cool . Erin's description of the Bose 901(not the bad tonality part) kinda reminded me of my experience with the MBLs. It's a sound that's hard to dislike, even though it sounds far from "real"(imo). I've heard Ohms too, but supposedly they're not true omnis.

That's the problem with subjective impressions, though. We hear the *same* speakers(not sure which MBLs you owned), but leave with totally opposite(though both positive) impressions .

Fair enough. As I've said before, if we are talking about a system sounding "more real," since all systems are compromised in one way or another, one person may latch on to what System A is doing "more realistically" and another person System B. (E.g. if someone is more focused on tonal/timbral accuracy a system doing better in that aspect will be the one he picks, where someone else may be all about scale and dynamics sounding more real, and be less particular about tonal neutrality).

While it's certainly interesting that our impressions of the MBLs diverge, I think it brings up a more pertinent question: how much would our impressions actually diverge if both of us were listening to the same system - that is the MBLs in MY room? Then it would be a more apples to apples thing.

Omnis are very room/set-up dependent for obvious reasons, and as I've written before, I could control the acoustics of my room really well to dial down or up room reflections. I found I got an amazing balance where the room didn't seem to be swamping the recorded sound, and I got terrific focus of imaging (remember...it's the dispersion characteristics and hence room interaction of omnis that people cite for 'fuzzy imaging.)'

I've done direct live vs reproduced comparisons in my home, and nothing to my ears (and as someone obsessed with live vs reproduced) survived that comparison like the omnis.

And it translated in to lots of musical recordings. E.g. classical guitar recordings just sounded like instruments had been telaported in to my room (though with the original acoustic reverb accompanying) in a physical way like nothing else I've owned. Even the best "disappearing/soundstaging" cone-in-box speakers seemed like they were sort of "squeezing" the sound in a way that just said "recorded" where the omnis seemed to just release the boundaries and "breath" so that there was little sense of recorded artifice - just the sound of an instrument playing, with an astounding sense of natural resolution.

So, again, it would have been interesting to see if your impression might have been closer to mine had you heard them here.

(Reminds me of my friend who was convinced by all his encounters with Thiel speakers that they were too bright and "clinical" sounding, who then heard Thiels in my set up and did a 180, saying it was simply "spooky real" and it was the best sound he'd ever heard in my place).

 

[Mojo Warrior]

EPI M1000 were the best speakers I've ever heard. They need a big room and lots of power to really appreciate them.

These are reproductions: https://www.humanspeakers.com/e/epi1000.htm

Super Fun listening to Pink Floyd DSOTM back in the day. Also would make an awesome coffin!

 

[Flaesh]

Not home stereo but omnis:

 

[MakeMineVinyl]

Not home stereo but omnis:

That's kind of a bizarre setup.

 

[Flaesh]

And one more:

https://en.wikipedia.org/wiki/Federal_Taxation_Service presumably (?)

 

[KA7NIQ]

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.





o 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 eitTher.

One other thing, @Mr. Speakers: Referring to those you hope to persuade as "audiophools" is counter-productive.

Floyd Toole used the Mirage M1 for many years, at his home, until the people at Harman International started bitching, so he was gifted Revels, LOL
Whatever one might think of Floyd Toole and his theories and research, the Man has certainly heard and tested a zillion speakers, in his time.
Floyd re designed the Infinity Prelude when he was at Infinity. But, where they found at his home ? The answer is no! Instead, he chose a speaker he did not design, the Mirage M1
It has been said that the perfect speaker would be a physical impossibility, a pulsating sphere. The Mirage M1 does it's best to mimic a pulsating sphere, with close to omnidirectional radiation.

It is most unfortunate that Klipsch bought out API, who owned both Energy and Mirage. Some very very talented engineers lost their jobs!

 

[jhaider]

Floyd re designed the Infinity Prelude when he was at Infinity. But, where they found at his home ? The answer is no! Instead, he chose a speaker he did not design, the Mirage M1

Actually,
1) Dr. Toole wasn’t a speaker designer. I think this myth started from a badly written review in Stereophile by one of their lesser writers, that wasn’t cleaned up in editing.
2) These look a lot like Infinity speakers to me:

Advice From an Audio Insider

Harman engineer Dr. Floyd Toole's own home theater is surprisingly achievable. That's because he's a regular guy like you.

www.soundandvision.com

It is most unfortunate that Klipsch bought out API, who owned both Energy and Mirage. Some very very talented engineers lost their jobs!

Agreed. Both had interesting, and very different, lines. Energy’s top speakers had all the driver technologies around and superb integration. Mirage’s OMD line looked superb and offered a different, well engineered but different, take on home loudspeakers.

 

[nerdoldnerdith]

Floyd Toole used the Mirage M1 for many years, at his home, until the people at Harman International started bitching, so he was gifted Revels, LOL
Whatever one might think of Floyd Toole and his theories and research, the Man has certainly heard and tested a zillion speakers, in his time.
Floyd re designed the Infinity Prelude when he was at Infinity. But, where they found at his home ? The answer is no! Instead, he chose a speaker he did not design, the Mirage M1
It has been said that the perfect speaker would be a physical impossibility, a pulsating sphere. The Mirage M1 does it's best to mimic a pulsating sphere, with close to omnidirectional radiation.

It is most unfortunate that Klipsch bought out API, who owned both Energy and Mirage. Some very very talented engineers lost their jobs!

The speakers that have the closest thing to a pulsating sphere launch pattern are those designed by Morrison Audio. I own a pair and they do indeed sound very good with the right material, but I think it would be a mistake to call that design "perfect." Most material simply isn't mastered to be reproduced on speakers like them, and they don't do a great job for movies and stuff like that.

In reality there is no such thing as a perfect speaker. Audio reproduction is not so simple.

 

[Duke]

Floyd Toole used the Mirage M1 for many years, at his home, until the people at Harman International started bitching, so he was gifted Revels, LOL

What is your source for this information?

I'm under the impression that when Dr. Toole was hired by Harman he left Canada and moved to California and did not not bring his Mirage M1's with him, and if my impression is correct then there was no significant overlap where he worked for Harman while owning Mirage speakers... BUT I could EASILY be mistaken.

 

[Newman]

Floyd Toole used the Mirage M1 for many years, at his home, until the people at Harman International started bitching, so he was gifted Revels, LOL
Whatever one might think of Floyd Toole and his theories and research, the Man has certainly heard and tested a zillion speakers, in his time.
Floyd re designed the Infinity Prelude when he was at Infinity. But, where they found at his home ? The answer is no! Instead, he chose a speaker he did not design, the Mirage M1
It has been said that the perfect speaker would be a physical impossibility, a pulsating sphere. The Mirage M1 does it's best to mimic a pulsating sphere, with close to omnidirectional radiation.

Here are Dr Toole's thoughts on people misusing his ownership of M1 speakers as a sign that he thinks it is the best speaker, and speaking for him in general, link 1.

Dr Toole is also quick to point out that live music is not omnidirectionally-radiated from its sources, and that other speaker types more closely radiate in the manner of critical instruments and voices. I have expanded on that point, with reference to Dr Toole, earlier in this very thread, link 2.

And finally, Dr Toole has explained how the M1 was a specific solution to a very large and reverberant room, with a large listening distance, and sacrificed imaging, link 3. He has also, link 4, described omnis as sound effect generators for people stuck with stereo, who are willing to add spaciousness at the cost of losing imaging -- whereas we can have both spaciousness and imaging with multichannel forward-firing speakers.

cheers

 

[dasdoing]

that's an intresting aprouch, but especialy voice will be centered. How does the DI of a phantom center look like?

 

[KA7NIQ]

What is your source for this information?

I'm under the impression that when Dr. Toole was hired by Harman he left Canada and moved to California and did not not bring his Mirage M1's with him, and if my impression is correct then there was no significant overlap where he worked for Harman while owning Mirage speakers... BUT I could EASILY be mistaken.

I used to own Infinity Prelude PFR Speakers, designed by Laurie Fincham and Andrew Jones. Laurie brought Andrew Jones from England to Infinity when he left KEF. I used to call Infinity after Floyd Toole came, with his team of Canadiens, including Alan Deventier who is ex Paradigm, and Sean Olive. Floyd never told me he was using the Mirage M1. I think I either read it in his book, or on some audio related forum ?
One of the first things Floyd Toole did at Infinity was to effect a redesign of the Infinity Prelude PFR. I was told that Floyd was not a fan of the D'Appolito MTM design of the original Infinity Prelude PFR. The Original Infinity Prelude PFR was compromised because it had a small woofer enclosure, and not a very powerful woofer amplifier. Floyd did away with the MTM alignment, and also gave the Prelude a much more robust woofer, and a much more powerful woofer amplifier.

 

[Flaesh]

And more :

 

[KA7NIQ]

No discussion on Omnidirectional Loudspeakers is complete w/o mentioning these. These are the DBX Soundfield 1A Speakers.

 

[fpitas]

Wow. Guess none of the senior members have tried omni, planer, electrostatic, etc. Been there.

Planar and electrostatic are very far from being an omni point source. The polar pattern is a series of lobes centered on each side, that get quite byzantine at higher frequencies.

 

[BenB]

No discussion on Omnidirectional Loudspeakers is complete w/o mentioning these. These are the DBX Soundfield 1A Speakers.
View attachment 222076

It looks to be a poor omnidirectional speaker, but a great interference machine.