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Omnidirectional loudspeakers ?

svart-hvitt

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Very much agree with you! Although given that many people will - whether owing to budget, space, or habit - have only two speakers in their room, I don't think it's fruitless to ask what the best way to do it is, within this limitation.

I think multcihannels can be smaller than conventional stereo speakers (part physics and part psychoacoustics, I reckon), so you can buy smaller-cheaper channels.

5 x Genelec 8341 and 2 x 7380 would be more than most «need». Cost is about $25k for a complete system. How much is a pair of Revels?
 

svart-hvitt

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Multichannel requires a tighter sweetspot, though, unlike omni speakers. But I agree, multichannel is probably the superior alternative for those who can manage to arrange it in their homes - at least in the sweet spot.

I am not so sure about the sweetspot thing. When the sound is immersive, in a genuine way, I think you will think of multi-channel sweetspot a bit differently compared to stereo sweetspot.

It’s not like omni math is intelligent and creates a sweetspot wherever you want it either ;)
 

andreasmaaan

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I am not so sure about the sweetspot thing. When the sound is immersive, in a genuine way, I think you will think of multi-channel sweetspot a bit differently compared to stereo sweetspot.

It’s not like omni math is intelligent and creates a sweetspot wherever you want it either ;)

Do you have a multich setup @svart-hvitt? I think I'm gonna do one in this studio I'm building when I finally finish it...
 

svart-hvitt

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Do you have a multich setup @svart-hvitt? I think I'm gonna do one in this studio I'm building when I finally finish it...

I heard a mch setup based on even smaller Genelecs. And this convinced me how good a mch setup based on good speakers in a DSP environment can be. The clarity was mind boggling! I heard the same sound in another «competent» setup (no DSP, conventional bigger speakers) and the difference was depressing... I walked around in the circle, of say 3-3.5 meters in diameter, and the sound was «there» all the time.
 

pierre

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Do you have a multich setup @svart-hvitt? I think I'm gonna do one in this studio I'm building when I finally finish it...
I have one: 5 focal trio + 6 focal shape small one + 2 subs. I use a daw and a NUGEN plugin to generate a 5.2.4 sound.
After that I have a convolution plugin for room correction (with various latency trade off).

The main surprise for me is that it is much harder to hear the room correction effect. In stereo that’s obvious.
 

Kal Rubinson

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I have a set of the multichannel Beethoven symphonies from Tacet I’m waiting to try.
Performance is OK if a bit scrappy. Sound is too unnaturally immersive, by intention, for my enjoyment.

IMO multichannel done well in the new frontier in better sound reproduction, but it’s impractical for most people in most rooms.
All it takes is a commitment.
 

Kal Rubinson

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I am not so sure about the sweetspot thing. When the sound is immersive, in a genuine way, I think you will think of multi-channel sweetspot a bit differently compared to stereo sweetspot.
Agreed. The concept of a sweet spot is a result the severely constrained soundstage present in stereo. Taking that concept to a good multichannel system shifts the onus to the production of the source material.
 

MattHooper

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I think @Floyd Toole asks the right question: Why not bring the right equipment to the job?

If the job is creating an immersive sound, multichannel is the tool. Choose good speakers on conventional metrics to do the job of each channel.

That certainly makes sense if taken as a narrow goal, and for certain tastes.

On the other hand, many people find that two speakers is the most they want to deal with, and getting a nice spacious stereo image isn't that hard with two speakers.

In my home theater/listening room I have both: A dedicated surround set up (with projection screen) and a separate system for 2 channel (a pair of speakers for two channel listening, positioned closer to the seating position, and driven by a separate amps/sources). That's of course not the "easy way" but an even more complex route than most want to go. I listen to music on both systems. But I generally prefer listening via the stereo speakers. While the sound doesn't surround me to the degree of the surround sound, the two channel presentation is still extremely spacious and quite immersive (I've often had guests listening ask if it was surround sound!), and the sense of instruments detached from speakers and floating in localized focused space is more pleasurable and 'convincing' to me.

I don't think my surround sound set up is too bad btw: At least one professional home theater installer said it was the most coherent, immersive home set up he'd heard. However, I recognize there are leagues in surround sound performance beyond what I have (which is merely a good 5.0 system). I'm just commenting that, sure going all out for a killer surround system will get the most sonic immersion, but there are still reasonable positions on why many don't go that route over a 2 channel set up which can still produce an excellent spatial presentation without the added complexity.
 

Theo

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What about well focused stereo speakers (Kii or D&D, for example) to which you add convolution reverberation to mimic omni? So you get to choose;)
While, of course, surround 5.1 would be better at this game:)
 

Bald1

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One of the most memorable in store listening experiences I ever had was with the old Magnepan 8 panel setup.

That was my first exposure to Magnepan as well. Some boutique audio store in the SF-Berkeley area. Not omni-directional but bipolar, the Tympani I-D 8 panel array was driven by a stack of Bryston amps and the sound was glorious.

It took decades but I finally ended up with a set of IIIa whose crossovers I tweaked and added a big 18" sub to the mix. They were used but in great condition with new tweeter ribbons. Made a great 1999 Christmas gift to myself. Been using them ever since. Drive them with Odyssey Audio monoblocks.

glow_1.JPG
 
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LTig

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Sounds like what they say about boats. People love Maggies. For whatever reason there are ML electrostatics in every Magnolia Design store making them the most available panel speaker in the USA. However, Harman has done some great research and their products show it.

Just because there is a statistically significant preference does not mean everyone has that preference.
Tastes can change with time. In 1989 I heard the MG 1.6 at a dealer where I had recently purchased a DAC, fell in love, took them home and never brought them back. They replaced a DIY speaker based on the KEF CS7.

15 years later I helped a colleague to find new speakers, and on this quest we finally went to a dealer for musicians who had lots of nearfield studio monitors ready to hear. There my colleague bought a pair of small 3-way active studio monitors. I liked them as well but financially they were a bit out of reach, and I was not very unsatisfied with the Maggies. About 6 months later I stumbled about a very good offer in the bay and bought them. The first thought which entered my mind after hearing them for the first time in my home: "I didn't know the Maggies were sooo bad!". So clean, so precise, such a solid imaging, such a deep bass. On the other hand the Maggies were more forgiving with really bad recordings - everything sounded nice and "big".

But going back was no longer an option. After another 15 years these monitors are still running (while I write this and listen to Metallica black album declipped), just helped by a subwoofer in the mean time.
 

Ron Texas

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Most 3 way active monitors are pricey.
 

Duke

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Did Toole/Olive/Harman measure any omni’s?

No, but there's this guy named Amir who measured and evaluated an omni on that crazy ASR forum.

It was just an inexpensive little desktop thing, and its calculated Preference Rating was the absolute WORST: -0.1. That's a NEGATIVE score! I didn't know that was even possible.

Now this isn't what we'd call a "serious" speaker, but despite the unbelievably bad Preference Rating, Amir liked it enough to recommend it!

How might a "serious" omnidirectional speaker have scored, and would Amir have recommended it? I hope we find out some day.

Omni’s, I have heard MBLs,Audio Physiks at Munich, Beolab 90 has an omni mode which I found a little disorientating, Shahinians of various hues, although they aren’t true omni’s , are they just toys or do they have any merit.

At the risk of oversimplifying, the primary benefit of a good omni is that it generates an exceptionally well-energized and spectrally correct reverberant field, which can do an excellent job of conveying natural-sounding timbre and effectively presenting the reverberation cues on the recording (which in turn convey a sense of immersion).

The primary drawback of omnis is that they tend to put a lot of energy into the early reflections, which are the ones most likely to degrade imaging precision and clarity.

So, omnis generally sound best positioned well away from the walls in a large room, which is how MBL likes to show their big Radialstrahlers. This pushes those early reflections far enough back in time that they are no longer detrimental. In smaller (inadequately treated) rooms, ime there is an audible "small room signature" with omnis which can be distracting. But well set-up in a nice big room, they can be magnificent.

In my opinion the improvement from "small room - yuck" to "big room - OMG!!" is not adequately explained by simply adding a few milliseconds more time delay to the reflections. Instead, here is what I think is happening:

In the small room, the relative abundance of early reflected energy tells the ear/brain system "you're listening in a small room".

But in the big room, the relative absence of early reflected energy (especially in comparison to the abundance of later-arriving reflected energy) does not convey a strong "small room signature", and at the same time all those late reflections are delivering the ambience clues on the recording from all around, so the recording venue cues dominate. We go from primarily hearing the playback room to primarily hearing the recording venue, and imo that difference is huge.
 
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Purité Audio

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I very much like B&O’s ‘omni’ implementation in their Beolab90, because you can turn it off.
Keith
 

Duke

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I very much like B&O’s ‘omni’ implementation in their Beolab90, because you can turn it off.
Keith

The Beolab 90 may have an enormous amount to teach us!

It is probably the closest we can get to an "apples to apples" comparison between narrow-pattern and omni speakers. MUCH moreso than Salon2 vs JBL M2.

And while the Salon2 won its shootout by a small margin, from what I've read by Kal Rubinson and others, the narrow-pattern setting wins decisively on the Beolab 90.

I speculate that ONE of the reasons for the different outcomes is this: The Beolab 90 comparisons were done in stereo, while the Salon2 vs M2 shootout was done single-speaker vs single-speaker. I think the ear likes a fair amount of reverberant energy, which a single Salon2 delivered while a single M2 did not, but a stereo pair of Beolab 90's delivers enough reverberant energy while avoiding detrimental early reflections.

One way to test this speculative hypothesis would be to audition the Beolab 90 as a single speaker, to see if preference shifts towards wide or omni mode in single-speaker listening.

(If it sounds like I'm waffling back and forth between narrow and wide/omni patterns, it's because my preference is for minimal early reflections followed by plenty of late reflections... so I'm trying to cherry-pick some of the best attributes of both, but without "resorting" to multi-channel.)
 
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oivavoi

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Haven't logged on here for ages given that I need to hand in my PhD thesis (getting closer by the day). But given that this is my favorite hifi topic, probably, I need to chime in.

Concerning the Beolab 90 I also prefer the wide and narrow modes to the omni mode. This comes from one who likes omni speakers! The reason is simply that the dispersion of the Beolab 90 is very pretty in narrow and wide mode, but it is not pretty in omni mode. This can clearly be seen in the polar plots, which B&O chief engineer Geoff Martin made available on his excellent blog:
http://www.tonmeister.ca/wordpress/2015/11/04/bo-tech-intuitive-directivity-plots/

Narrow mode:
narrow_contour.png


Wide mode:
wide_contour.png


Omni mode:
omni_contour.png

As Geoff Martin wrote:
"The directivity of BeoLab 90’s Omni mode is shown below in Figures 15 and 16. The lobing caused by the distances between the tweeters is visible in the contour plot, however, as you can see in Figure 16, there is certainly energy being directed in all directions across the entire frequency spectrum. However, the high-frequency lobing, in addition to the beaming in the lower midrange area would indicate that this mode is not appropriate for critical listening… "

My take-away is that the Beolab 90 is an amazing loudspeaker in wide and narrow mode (the dispersion is actually most even in narrow mode). But there are certainly much better executions out there of omni dispersion.
 
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Duke

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Concerning the Beolab 90 I also prefer the wide and narrow modes to the omni mode. This comes from one who likes omni speakers! The reason is simply that the dispersion of the Beolab 90 is very pretty in narrow and wide mode, but it is not pretty in omni mode. This can clearly be seen in the polar plots, which B&O chief engineer Geoff Martin made available on his excellent blog:
http://www.tonmeister.ca/wordpress/2015/11/04/bo-tech-intuitive-directivity-plots/

Good to hear from you, thanks for taking a break to post!

And thank you very much for the link. I had assumed "narrow mode" was considerably narrower than it turns out to be. Looks like it's about 100 degrees (-6 dB limits). This IS narrower than the JBL M2, but not as narrow as many if not most horn systems.

That is amazing pattern control, especially down low. Wow.
 
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Rick Sykora

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My foray into omnidirectional sound was Mirage OMDs. Initially, they seemed better, but eventually got moved into surround duty. Once I had been seduced by the crisp image of a well-configured monopole, it was hard to accept a more diffuse soundfield. Unfortunately, the monopole gig was a tease as it only happens with well-produced recordings. My CBT24s seems to be a good middle ground between the Mirages and my numerous monopoles. As for the multi-channel approach, I have experimented, but with most music, it seemed like I had to do a lot of setup to get marginally better results...

Some of my "just like being there moments" are actually from waning quad era. Audio became my hobby in the fading days of quadrophonic. Aside from a Dual turntable, most of my equipment was pretty mediocre by today's standards. After replacing a Realistic "quad" receiver with a solidly-built Pioneer, I still had rear speakers. Running them at full power was annoying, and then I ran across Hafler's passive matrixing circuit. I soon had it built and wired up. I recall getting startled out of my seat once when the TVs get smashed in The Wall. With today's surround processing that circuit is collecting dust in the basement, but aside from the recording making a difference, my takeaway was that surround worked well when in was subtle. With active matrixing today, I often find that the surround is rarely just right. Often it is too obvious or not much difference. I use the surround for movies, but listening is still mainly stereo for me. :)
 

escott82

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I quite like my omd 5’s and omdc1 as I’ve kept them for about 13 years now. I think the center speaker is pretty well focused. It’s not in your face like other systems I’ve heard but turn the volume up enough and these little speakers sound great with music and movies. I’m using some omnisat v2’s as my atmos speakers and the sound is huge.
ive been curious to replace the front three with more directional but keep the omd5’s as surround’s and maybe move them up to atmos channels but not sure I can mix the two systems together with lcr being so different? Thoughts? I do like ribbon tweeters they seem to sound similar to the mirage diffused titanium tweeter.
 

Rick Sykora

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I quite like my omd 5’s and omdc1 as I’ve kept them for about 13 years now. I think the center speaker is pretty well focused. It’s not in your face like other systems I’ve heard but turn the volume up enough and these little speakers sound great with music and movies. I’m using some omnisat v2’s as my atmos speakers and the sound is huge.
ive been curious to replace the front three with more directional but keep the omd5’s as surround’s and maybe move them up to atmos channels but not sure I can mix the two systems together with lcr being so different? Thoughts? I do like ribbon tweeters they seem to sound similar to the mirage diffused titanium tweeter.

My OMD-5 are my surrounds and a third one is my center. Of 5 centers I’ve owned, it is the only one that has been transparent. Tried Omni 150s for Atmos and did not work out as well. Have had various monopoles as mains and the mirage always worked well as center. As long as you can have Audyssey or some decent room eq., the mismatch has been less of an issue for me.

Before my CBTs, had bg radia z7 as mains. They use a planar tweeter and liked that too. The CBTs just do a better job of widening the sweet spot for more listeners. Hope this helps a bit. :)
 
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