Omnidirectional loudspeakers ?

[escott82]

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.

I’m always curious how others with the omd lines ventured off into other types of speakers and what compares. Have you ever tried the omdc1 for a center? I also have v2fs floor standers in the bedroom. Why didn’t the omni 150’s work too well for atmos? Too diffused for you? I feel like having the v2 bookshelf’s for atmos expands the whole feel of the movie/music to me. I do have to do a bit of aiming and toe for them to sound best to me too.

 

[Kal Rubinson]

Are any of the OMD's really omnidirectional?

 

[escott82]

Are any of the OMD's really omnidirectional?

Its 30% direct sound 70% reflected. So you can aim them to a degree.
Mirage sound

 

[Kal Rubinson]

Its 30% direct sound 70% reflected. So you can aim them to a degree.
Mirage sound

Sure.

 

[Rick Sykora]

I’m always curious how others with the omd lines ventured off into other types of speakers and what compares. Have you ever tried the omdc1 for a center? I also have v2fs floor standers in the bedroom. Why didn’t the omni 150’s work too well for atmos? Too diffused for you? I feel like having the v2 bookshelf’s for atmos expands the whole feel of the movie/music to me. I do have to do a bit of aiming and toe for them to sound best to me too.

no on the omdc1 as already had the extra omd5. yes, suspect the omni 150 was too diffuse as I replaced the tweeter with a vifa dome and liked better. also was using them along side of room on high shelves. they seemed best lying face down almost as if mounted in ceiling.

am not doing atmos currently as the yamaha receiver supporting it is now on duty in another room. My hope was to get better flyover effect and it was pretty marginal improvement imo. what frontend are you using?

 

[escott82]

no on the omdc1 as already had the extra omd5. yes, suspect the omni 150 was too difuse as I replaced the tweeter with a vifa dome and liked better. also was using them along side of room on high shelves. they seemed best lying face down almost as if mounted in ceiling.

am not doing atmos currently as the yamaha receiver supporting it is now on duty in another room. My hope was to get better flyover effect and it was pretty marginal improvement imo. what frontend are you using?

I’m not sure about the 150’s they seek similar to the omd5’s though. Over 6 feet they need to be flipped upside down. That’s the way I have all the V2’s handling the 4 height channels.
front room is 7.4.4
Omd 5’s L/R omdc1 center. Surround speakers are also omd5’s. Rear surrounds are v2’s like the heights.
In my room is similar with the v2 whole system with the v2fs floor standers v2cc and more of the v2 bookshelf’s for atmos front and side surrounds. 5.2.4.
I got a really good deal on these v2 bookshelf’s and floor standers last year. Couldn’t pass them up had to resurround most of the bookshelves but 50$ for 10 of them is a deal I had to take.

 

[jhaider]

Are any of the OMD's really omnidirectional?

I have a pair of OMD-5. I haven't measured them 360 degrees, but here's 0-90 horizontal at 10 degree intervals (reference axis tip of the tweeter dome). Vertical axis is -15dB to -70dB.

I don't think they're great sounding speakers. In Karelia burl birch they look fantastic on my desk at the office desk though.

 

[krabapple]

I was debating this - the psychoacoustic "evidence" on preference for or against omnis - at another forum some time ago. When I looked into the research, I saw that omnis have fared very well in all the experiments I could find where an omni was compared to a dipole or a conventional forward-firing speaker.

Flindell 1991 and Bech 1994 were direct comparisons of omnis and other designs (but Bech doesn't discuss it himself, his data were re-analyzed by Evans et al in 2009). In Flindell's study naive listeners preferred omnis, while professional listeners found the omni and the conventional speaker equally good. In Bech's study, the omni and the dipole came out on top.

As mentioned in the thread, the almost-omni Mirage M1 scored higher than any other speaker at the NRC in Canada during the 80s, so much so that dr. Toole chose it himself.

Choisel 2005 did a comparison of a conventional speaker with the Beolab 5, which is semi-omni, with regards to imaging. Beolab 5 imaged as good as the other one. This text isn't available online, but the results are discussed in depth in dr. Toole's book.

David Clark did extensive blind testing in 2010 of three speakers, the dipole Linkwitz Orions, a pair of cheap Behringer monitors, and "The Imp", a DIY quasi-omni speaker by Gary Eickmeier. The outcome of interest was "plausibility of the auditory scene", and the DIY quasi-omni came out on top.

Those Eickmeier quasi omnis, btw, were rather like....Bose 901s.

 

[GXAlan]

One good content the MBLs sound really good. The issue I have is that everything played through them has the same signature, diffused soundstage. Not every piece of content should sound that way.

This is why people need multiple speakers and multiple listening rooms!

 

[krabapple]

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.

Movie theaters are multichannel.

Also, my experience with home 5.1 -- I upmix everything -- is that the sweet spot is *not* as critical there either. Obviously having a center channel helps anchor the center 'image' in ways that two channel cannot

As Dr. Toole notes, multichannel reproduction further takes the 'room' out of the equation, and is actually more forgiving than two channel..

I am getting the impression that few posters here actually have extensive experience with anything beyond 'stereo' at home. There are thousands of multichannel releases available at this point (mch has been a commercial music thing since circa the year 2000, and I've been 'consuming' them since then) and a variety of tools available to AVR owners for upmixing plain old 'stereo' recordings as well.

I havn;t used 'omni'-like loudspeakers for many years now...the last being the much touted (in Stereophile or TAS) Optimus (Radio Shack) LX5 Linaeum tweeter dipoles in the 1990s. For multichannel, which I;ve adopted wholeheartedly since then, dipole/omni would NOT be the tools of choice. Dipole surrounds could work in home theaters for some movie soundtracks and mch music recordings where 'ambience' is all that's in the rear channels, but for 'discrete' multichannel mixes, they're a bad idea.

 

[escott82]

Movie theaters are multichannel.

Also, my experience with home 5.1 -- I upmix everything -- is that the sweet spot is *not* as critical there either. Obviously having a center channel helps anchor the center 'image' in ways that two channel cannot

As Dr. Toole notes, multichannel reproduction further takes the 'room' out of the equation, and is actually more forgiving than two channel..

I am getting the impression that few posters here actually have extensive experience with anything beyond 'stereo' at home. There are thousands of multichannel releases available at this point (mch has been a commercial music thing since circa the year 2000, and I've been 'consuming' them since then) and a variety of tools available to AVR owners for upmixing plain old 'stereo' recordings as well.

I havn;t used 'omni'-like loudspeakers for many years now...the last being the much touted (in Stereophile or TAS) Optimus (Radio Shack) LX5 Linaeum tweeter dipoles in the 1990s. For multichannel, which I;ve adopted wholeheartedly since then, dipole/omni would NOT be the tools of choice. Dipole surrounds could work in home theaters for some movie soundtracks and mch music recordings where 'ambience' is all that's in the rear channels, but for 'discrete' multichannel mixes, they're a bad idea.

But why do you think they aren’t directional also. There is never a point where I feel like things seem blurred. The openness is huge and panning is really really good with omni. Depends what kind of speakers they are but it’s not like all Omni’s are the same. It’s not a blurred mess with no distinction of location. Center image is still plenty focused for me. Maybe time to give more speakers a shot. Surrounds are amazing with omni also.

 

[krabapple]

A two channel omni system can't replicate a true multichannel experience, sorry. And I didn't say anything was a blurred mess. Please see what Dr. Floyd toole has to say here about dipole speakers.

 

[Rick Sykora]

Surround dipoles have a much different radiation pattern than dipoles like Linkwitz’s LX521. Dr. Toole’s quote in the AH article is about surround dipoles. Surround dipoles intentionally create a more diffuse forward sound field to try to obfuscate localization. The rear radiation of the LX521 dipole combines with the forward field of a monopole to provide the listener with more spatial clues. If you listen to the AH video, Gene mentions that dipoles can be convincing as main speakers. Toole might not agree, but Linkwitz felt differently.

If I were forced into a sound system with fewer speakers (would make my wife happier!), I would not hesitate to try dipoles as main speakers. I have heard many more positive experiences than negative ones from reputable experienced listeners.

 

[Floyd Toole]

Surround dipoles have a much different radiation pattern than dipoles like Linkwitz’s LX521. Dr. Toole’s quote in the AH article is about surround dipoles. Surround dipoles intentionally create a more diffuse forward sound field to try to obfuscate localization. The rear radiation of the LX521 dipole combines the forward field of a monopole to provide the listener with more spatial clues. If you listen to the AH video, Gene mentions that dipoles can be convincing as main speakers. Toole might not agree, but Linkwitz felt differently.

If I were forced into a sound system with fewer speakers (would make my wife happier!), I would not hesitate to try dipoles as main speakers. I have heard many more positive experiences than negative ones from reputable experienced listeners.

There is absolutely nothing wrong with conventional - true - dipole loudspeakers. They are free-standing full-range speakers radiating identical sound fields forwards and backwards, but in opposite polarity. An ideal dipole has a figure-of-eight polar pattern over most of the frequency range, with cancellation dips at +/- 90 deg. As might be expected there are both good and less-good dipoles, as with any other configuration.
Surround dipoles are NOT true dipoles. They are wall-mounted bidirectional partially out-of-phase creations, in which the (monopole) woofer radiates conventionally in the forward (across the room) direction with wide dispersion up to the crossover frequency (typically 1-2 kHZ). In the most common configuration two tweeters, facing somewhat forward and backward, are connected out-of-phase creating a dreadfully irregular cancellation dip in the middle and upper frequencies of what is the direct sound for listeners. The sound quality, which is dominated by the direct sound, cannot be neutral. The claimed "diffuse" sound field cannot exist in the small acoustically "dead" rooms in which we live, nor would we want one. The perceptual illusions are also dominated by the direct sound. These concoctions were invented in the short time period when multichannel audio had only four channels - a single mono channel for the two surrounds. It was thought that they had advantages, and were patented by THX. Since then the surround channels have been independent and any necessary interaural (between the ears) decorrelation is created in the mix by the recording engineers who do not listen to "dipole" surrounds - no additional meddling is necessary. Nowadays, there is no justification at all for the bidirectional out-of-phase ("dipole") configuration, but the bidirectional in-phase (bipole) configuration can be useful because of its wide dispersion in narrow rooms with multiple rows of listeners. In modern multichannel systems all loudspeakers need to have basically the same radiation pattern and sound quality if the overall directional and spatial effects are to be both persuasive and satisfying. That is how the pros listen.

 

[Rick Sykora]

There is absolutely nothing wrong with conventional - true - dipole loudspeakers. They are free-standing full-range speakers radiating identical sound fields forwards and backwards, but in opposite polarity. An ideal dipole has a figure-of-eight polar pattern over most of the frequency range, with cancellation dips at +/- 90 deg. As might be expected there are both good and less-good dipoles, as with any other configuration.
Surround dipoles are NOT true dipoles. They are wall-mounted bidirectional partially out-of-phase creations, in which the (monopole) woofer radiates conventionally in the forward (across the room) direction with wide dispersion up to the crossover frequency (typically 1-2 kHZ). In the most common configuration two tweeters, facing somewhat forward and backward, are connected out-of-phase creating a dreadfully irregular cancellation dip in the middle and upper frequencies of what is the direct sound for listeners. The sound quality, which is dominated by the direct sound, cannot be neutral. The claimed "diffuse" sound field cannot exist in the small acoustically "dead" room in which we live, nor would we want one. The perceptual illusions are also dominated by the direct sound. These concoctions were invented in the short time period when multichannel audio had only four channels - a single mono channel for the two surrounds. It was thought that they had advantages, and were patented by THX. Since then the surround channels have been independent and any necessary interaural (between the ears) decorrelation is created in the mix by the recording engineers who do not listen to "dipole" surrounds - no additional meddling is necessary. Nowadays, there is no justification at all for the bidirectional out-of-phase ("dipole") configuration, but the bidirectional in-phase (bipole) configuration can be useful because of its wide dispersion in narrow rooms with multiple rows of listeners. In modern multichannel systems all loudspeakers need to have basically the same radiation pattern and sound quality if the overall directional and spatial effects are to be both persuasive and satisfying. That is how the pros listen.

Thanks for the clarification! Have extensively studied your work as well as that of Linkwitz and Don Keele. I have a pair of Don's CBTs and so have experienced what they can do. As you have indicated in your writings, there is a broader sets of problems to be solved if we are to improve sound reproduction. I do not know whether the speaker answer is different drivers, more drivers, more processing or different configurations, but am pretty clear it is beyond what the mainstream offers today.

It is encouraging to know that you are more open minded about dipoles than some may have thought. Your position on CBT speakers is not well known. It seems to have been summarized as they might be good surround speakers. As JBL has commercialized them, am guessing you may have more than a passing experience with the technology. Please let us know if you have more insights that you might share?

 

[krabapple]

Surround dipoles have a much different radiation pattern than dipoles like Linkwitz’s LX521. Dr. Toole’s quote in the AH article is about surround dipoles.

Yes, and that's what I was referring to too.

 

[Rick Sykora]

Have been contemplating building LX521s, but went back to the Linkwitz lab website and found this...

"The speakers need breathing room of at least 1 m to the nearest large reflecting surfaces and a room with a minimum volume of 65 m3."

While not a huge room, it would need to be fairly wide and dedicated space. I really do not have that sort of space (mainly width) in my current home. Along with having to figure out how to the disguise the upper baffle for my wife, not sure they are worth the investment. Think I want to try something more than an LXmini. Had also considered these: http://gainphile.blogspot.com/2012/06/s20-z-compact-open-baffle-using-zaph.html but the bright aluminum from the Zaph midwoofer is distracting in my home theater.

Am back to designing my own unless someone here has a good recommendation?

 

[richard12511]

Have been contemplating building LX521s, but went back to the Linkwitz lab website and found this...

"The speakers need breathing room of at least 1 m to the nearest large reflecting surfaces and a room with a minimum volume of 65 m3."

While not a huge room, it would need to be fairly wide and dedicated space. I really do not have that sort of space (mainly width) in my current home. Along with having to figure out how to the disguise the upper baffle for my wife, not sure they are worth the investment. Think I want to try something more than an LXmini. Had also considered these: http://gainphile.blogspot.com/2012/06/s20-z-compact-open-baffle-using-zaph.html but the bright aluminum from the Zaph midwoofer is distracting in my home theater.

Am back to designing my own unless someone here has a good recommendation?

Man, I would really love to see one of those on the Klippel. Could be quite informative as a reference to what some other designs outside of the standard Toole speaker should be striving for.

 

[TSB]

Man, I would really love to see one of those on the Klippel. Could be quite informative as a reference to what some other designs outside of the standard Toole speaker should be striving for.

Second that!

 

[Fledermaus]

Listened once to one local audiophile's smallish standmount MBLs and was not so impressed : great spaciousness but tonal balance quite not right, with recessed mids and overall dullness.
Good for comfy-cosy listening maybe, just not my cup of tea.