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omnidirectional loudspeakers = best design available

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#1
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".
 
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Thread Starter #3
....the typical response, unless you 1) see and understand the fundamental difference in measurement of standard speakers vs. omni 2) hear an omni system for yourself. For those interested in actual, realistic sound reproduction of live music, the difference with a good omni is so far superior to a standard speaker..... it's not even close.
 

Frank Dernie

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#4
....the typical response, unless you 1) see and understand the fundamental difference in measurement of standard speakers vs. omni 2) hear an omni system for yourself. For those interested in actual, realistic sound reproduction of live music, the difference with a good omni is so far superior to a standard speaker..... it's not even close.
Because the omni adds so much of the acoustics of the listening room to the sound you hear the acoustics of the original recording venue on live recordings is swamped.
IME omni speakers are impressive and euphonic but the spatial information of the recording is completely hidden and largely lost and a wide deep artificial space imposed over it.
This does not matter with most recordings, particularly modern ones, since recordings made in a studio with a manipulated mix from multiple microphones has no true "recording venue acoustics" anyway.
OTOH the older recordings made in iconic concert halls using 2 or 3 microphones are not rendered accurately at all.
My own recordings (2 channel no manipulation) sound nice but certainly the acoustic rendering are nothing like the original recording.
Euphonic but inaccurate sound IME.
I rather like it nevertheless but high fidelity to the recording? No.
 

anmpr1

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#6
Just some random thoughts:

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. Does this mean that an omni is best?

From a practical point, an omni is going to have a lot of problems reproducing a wide range of sounds at a reasonable price point. That was the big fault of the original Walsh driver. It was 'full range' (except for the bass) and crossoverless in the range it covered, but the driver was made of different materials from its apex to base (I think it was three different materials), each contributing their own sonic signatures, and related problems. I have no idea about the German Physiks, MBL--or even the current implementation at Ohm. I've not heard them, however in any case they are not 'cheap' to own. Not that that is or should be a disqualifying factor.

I have spent some time (I did not own them or listen to them in my own house) with the Harold Beveridge tall (ceiling to floor) electrostatic line source--not an omni, but a half omni. Through the use of a tall electostatic element and special lens, it sent out a 180 degree rather coherent sonic wave launch (the back wave was damped as it was out of phase--unlike a true omni which cannot be said to even have a 'front' wave, or any front at all). The two speakers were supposed to be placed on adjacent walls facing each other (not facing the listener). The resulting sound was definitely different, and was rather non-directional. You sort of moved around in a 'bath' of sound. Nothing like a conventional speaker, that much is certain. Did it sound like a 'live' musical instrument, more so that a conventional loudspeaker? I really can't say that it did.
 

gene_stl

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#7
This is a silly thread.

Like everything in engineering there are many ways to skin a cat, and many different use cases, and one size does not fit all.

I heard the Beveridges ages ago and they sounded excellent to me at the time. But I have to admit at the time I did have an expectation bias in favor of electrostats.

I never thought much of Ohm speakers when and where I heard them (often because I knew some folks that drank the Ohm F kool-aid). But at Axpona the German Physics did sound very good. But so did a lot of different speakers.

I was underwhelmed by the LX Minis that Madisound had. In spite of having been a great fan of SL.

Music does not emanate from point sources. We also, in spite of language referring to imaging, coherence, and sounds stage, are not really reconstructing anything remotely resembling an image in the sense that the word is used in optics.
 
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Frank Dernie

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#8
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. Does this mean that an omni is best?
The effect of the wide dispersion of any musical instrument and its interaction with the recording venue are picked up by the microphone.
The discussion is moot on pretty well every multi-track recording because all the "ambience" in such a recording has been added at the mixing stage so is artificial already.
Radiating the sound which was picked up by the recording microphone in a classic recording by an omni can not produce an accurate impression of the recording, nor, IMO and IME do wide dispersion speakers, however even the FR of the lateral dispersion.
It is a euphonic colouration which sounds nice, that is all.
 

anmpr1

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#9
The effect of the wide dispersion of any musical instrument and its interaction with the recording venue are picked up by the microphone.
Yes. What I probably didn't make clear was that I was addressing an idea which one sometimes comes across--and what I presumed was the basis of the OP. The argument that a loudspeaker should attempt to mimic the original sound spread of the instrument(s) in 360 degree space. That is, because an instrument spreads out the sound every which way, the loudspeaker ought to do it, to. Of course with a recording one is not hearing the original sound, but rather whatever the microphone picks up, which will always be a facsimile of the original sound.

This was the Bose non-sequitur. Bose's idea was that at a live event the listener heard a lot of reflected sound, which was true. But as you point out, all those reflected sounds were more or less captured by the microphone at its location. Subsequently adding additional spatial cues at the speaker (by bouncing the sound all over) simply further 'spatialized' material already in the recording. The result being a not very real copy of the recording, although the listener may have liked the sound the loudspeaker made, in their living room.

Each loudspeaker design is going to have a 'sonic signature'. Point source, line source, omni. And each is going to sound different, regardless of the recording. For instance, typical flat panel electrostatics tend to beam, requiring a 'sweet spot'. The Beveridge did not do that. However I can't say that the resulting Beveridge sound was any closer to the recorded source than more conventional panel speakers such as the old Acoustat, the original Quad, or the Roger West Sound Lab just because it didn't beam. It did things the others didn't (or couldn't) do, but I don't think it was better. Just different.
 

suttondesign

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#10
siegried linkwitz’s theory is that when reflections are allowed but controlled, your brain cancels out the effects and leaves you with a soundstage like that which was recorded. thus, he would say that the omni is too many uncontrolled reflections. i have used linkwitz designs for many years, and they are uncanny, even on engineered pop. the soundstage is broad and deep, and box resonances are gone.
 

anmpr1

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...i have used linkwitz designs for many years, and they are uncanny, even on engineered pop. the soundstage is broad and deep, and box resonances are gone.
Generally, if you get rid of the box, the box sound will be gone! :)

Is there an ASR-type Klippel measurement review of his LX 521 speaker, anywhere? I'm sure at his site measurement information is available in one form or another. Those whose ears I trusted claimed it was first rate. SL spent most of his adult life working it out.

Not a simple undertaking, probably too involved for the typical audiopersonage who is looking to take something out of a shipping carton and then hook it up to an amp.

His 'mini' is a much simpler design, but looks a lot like plumbing.
 

Killingbeans

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Duke

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#13
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.

Omnis put out much more energy into the reverberant field, which results in more early reflections (which are imo generally undesirable but at least the omni's early reflections are truly spectrally correct), as well as more late reflections (which are imo generally desirable). The best-sounding omni setups I have heard were in large rooms with the speakers positioned well away from the walls and the listening positions fairly close to the speakers, to preclude the potentially undesirable excess of early reflections.

An excess of reflections, and in particular an excess of early reflections, degrades clarity. Dipoles and other types of polydirectionals tend to not be as demanding in terms of room dimensions as omnis are.

Omnis generally result in a wider "sweet spot" than conventional speakers, and the tonal balance inherently holds up well throughout the room. But they are not the only type of speaker which does this.

In my experience (which includes years of ownership of omnidirectional loudspeakers) omnis tend to trade off image specificity for a greater sense of immersion. This is a generalization and is setup dependent.

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.

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

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#15
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.
Apparently some Bose speaker/s had a good reputation like that...?
 

JustJones

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#16
I had Ohm Walsh 2000 a few years ago. I liked you didn't need your head in a vice to get good sound. They were good speakers to relax and read a book you didn't get the presicion of directness. I talked to the President of the company and he said he tried to voice them as if sitting in "certain area of Carnegie Hall" can't remember which area exactly. Front center about a third way back maybe??
 

Harmonie

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#17
Isn't that a bit similar to out of phase speakers like those TV sound options that gives you the impression of wider soundstage and space effect ?
 

amper42

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#18
As none of the music I listen to is mastered using omni directional methods or speaker systems. It's fool hardy for me to believe an omni speaker setup will restore the original sound of the instruments. In fact, many instruments are directional by nature such as a trumpet or sax. In addition, if you have ever been to a concert the sound is delivered by PA or instrument speakers of some type. In fact, if you are using your speakers for home theatre a directional speaker is preferred if you hope to enjoy the sound engineers' intended effect.

While omni speakers can offer unique sound delivery options that can be fun to try, I have not discovered any yet that offer the dynamic power and clarity of a traditional speaker box design that follows the cues the sound engineer originally intended. However, with some acoustic and vocal recordings an omni speaker can offer a very pleasant experience. For these reasons, I doubt omni speakers will be much more than a small niche market for those inclined to try something different.
 

Alice of Old Vincennes

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#19
....the typical response, unless you 1) see and understand the fundamental difference in measurement of standard speakers vs. omni 2) hear an omni system for yourself. For those interested in actual, realistic sound reproduction of live music, the difference with a good omni is so far superior to a standard speaker..... it's not even close.
Wow. Guess none of the senior members have tried omni, planer, electrostatic, etc. Been there.
 

Alice of Old Vincennes

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#20
Because the omni adds so much of the acoustics of the listening room to the sound you hear the acoustics of the original recording venue on live recordings is swamped.
IME omni speakers are impressive and euphonic but the spatial information of the recording is completely hidden and largely lost and a wide deep artificial space imposed over it.
This does not matter with most recordings, particularly modern ones, since recordings made in a studio with a manipulated mix from multiple microphones has no true "recording venue acoustics" anyway.
OTOH the older recordings made in iconic concert halls using 2 or 3 microphones are not rendered accurately at all.
My own recordings (2 channel no manipulation) sound nice but certainly the acoustic rendering are nothing like the original recording.
Euphonic but inaccurate sound IME.
I rather like it nevertheless but high fidelity to the recording? No.
I would rather listen to a movie at a drive in theater from the playground or concession stand than listen to omni.
 

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