Omnidirectional loudspeakers ?

[Defi]

Very interesting design, for me too!

"To drive each of the SP drivers by dedicated amplifier after DSP (XO/EQ/Phase/Polarity/Delay/Gain, etc.)" is similar/identical to my approach (ref. here) even though in my present setup only L&R super-tweeters are in a kind of omni-directional (3D reverse-reflection dispersion) configuration (summary ref. here).

Since the LFR1100HP SP system looks to be 5-way-SP-high-level-input configuration, if the SP system (with no DSP and amp units) might come to my listening room, I would be able to simply connect it to my present 5-way 10-channel multi-amplifier setup having full DSP control by DSP "EKIO" in my Windows PC.

Indeed, I have read your thread a few times and did think of these speakers. I think my approach would be to handle the crossovers myself. Or rather, with some guidance from a professional likely. Long term goal would be getting familiar with something like that myself.

Honestly I thought it looked a bit gimmicky, but for as much as the sound of omni speakers (disregarding these aren't really omni) can come through the youtube video, and the anecdotes here, this seems like it would be an interesting expensive experiment.

The only answer is to try it... and horns. And CBTs.

 

[bargainguy]

Surprised no one has mentioned Ohm yet. Still rocking a pair of Walsh 4's from 1995.

Not my first trip to the Ohm rodeo. Had a pair of Ohm G's way back when, also with the Walsh driver, different design though.

Omni is not for everyone. I find with the Walsh 4's, the soundstage is spread out horizontally with not as much vertical depth. If you're looking for pinpoint imaging, this isn't it.

There really isn't a sweet spot with these speakers. Listening off-axis is just fine.

It's an acquired taste. Previous speakers to the Walsh 4's were Maggie MG-2's.

Talk about a difference! Dipole vs. omni. The Maggies made the soundstage tall, and the Walsh 4's made it wide. Your choice!

 

[Floyd Toole]

So... I have been wanting to inquire about thoughts on these speakers:

LFR1100HP Active Omnidirectional Speakers

The most realistic-sounding speakers ever? Indulge in your wildest audio fantasies with these hear-it-all wonders.

www.axiomaudio.com

but have not felt it was worth a new topic. So instead I will revive this one!

I am just curious if there is any reason to find that design of interest. Obviously there are no decent measurements of it. I had encountered them a long time ago online before I found this place and I thought they looked cool but have no experiences with omnidirectional speakers, and even less knowledge about if a design like this can pull it off.

Axiom has its own anechoic chamber, a duplicate of the NRCC chamber I used in my early research, and they calibrate the bass response using their own tower measurements as reference for each loudspeaker configuration - something I did not do. They also do blind listening comparisons. So their data has a reason to be accurate, although I have not personally done or seen a comparison. They actually make serious attempts to do things properly.

As for bipole/omni loudspeakers, I owned a pair of Mirage M1s, reported in Section 7.4.6 in the 3rd edition of my book. For my purposes then (about 1990), they were very rewarding, but seeing the measurements I expect the Axiom would be even better sounding and have considerably more output capability.

 

[Defi]

Probably couldn't ask for a better endorsement

 

[NTK]

Just in case someone is wondering how Axiom's "tower" for low frequency measurements looks like, here is a picture.

Subwoofer Measuring Tower - About the Research | AxiomAudio | Axiom Audio

For complete and accurate measurements, Axiom Audio has built a dedicated 90 foot tower which subwoofer prototypes are attached to. Learn more here.

www.axiomaudio.com

 

[Jim T]

I think we should ask. @Floyd Toole did Harman test omni speakers against others?

My guess is the omni is wrong for the model of what makes a good sounding speaker in Harman's testing. But maybe they've tested them all the same. I do seem to remember mention of testing the Mirage bipolar M1 and M3. I think over much of the frequency range those were pretty much omnidirectional.

Of course I'm still trying to figure out why panel speakers do so poorly at Harman, but sound so good to me.

Certainly an 80+ piece orchestra is producing and Omni sound, but not sure it would work in a small space and I would consider a 20 X 40 room still a small space.

 

[Floyd Toole]

Certainly an 80+ piece orchestra is producing and Omni sound, but not sure it would work in a small space and I would consider a 20 X 40 room still a small space.

Compared to a concert hall 20 x 40 (ft I presume) is a small venue. But multidirectional loudspeakers add reflections within it that embellish stereo slightly in a spatial sense, while compromising the precision of phantom images. Multichannel sound can do much better because it delivers the "large venue" reflections at the appropriate large delays from approximately the appropriate directions. But, in the end small room resonances convey small-room information and the short-delay reflections are still there; it is a room-within-a-room situation. Much of the time the large room impression dominates, which is fortunate.

Loudspeaker reproduction in small rooms is a limitation. Binaural techniques can be more rewarding but are not mainstream. It is described in detail in the 4th edition of my book.

 

[MarkS]

It's not "omnidirectional" in the sense of radiating equally in all directions in the horizontal plane, like the big MBLs, but that's not a criticism of the design; just a difference of opinion over use of the term.

I would have called it a "bipolar", and it's an imo exceptionally well thought-out bipolar, in that the rear-firing drivers evidently correct the power response such that it very closely matches the direct sound (according to the measurements they posted).

Fun fact: Axiom used to call these "bipolar", then at some point changed the description to "omnidirectional". Somebody there must have decided that was better marketing.

I had bipolar DefTechs for many years, and really enjoyed their presentation of orchestral music (what I mostly listen to).

What's perplexing to me about the Axiom design is the dual tweeters and midranges on each side (front and back). Vertical directivity must have some pretty bad lobing.

I wish somebody would make an updated Mirage M1.

 

[jhaider]

So... I have been wanting to inquire about thoughts on these speakers:

LFR1100HP Active Omnidirectional Speakers

The most realistic-sounding speakers ever? Indulge in your wildest audio fantasies with these hear-it-all wonders.

www.axiomaudio.com

but have not felt it was worth a new topic. So instead I will revive this one!

I am just curious if there is any reason to find that design of interest. Obviously there are no decent measurements of it. I had encountered them a long time ago online before I found this place and I thought they looked cool but have no experiences with omnidirectional speakers, and even less knowledge about if a design like this can pull it off.

I’m not sure why they bother with a ten thousand dollar speaker pair wrapped in fake wood look vinyl.

Surely anyone who is buying speakers that need to be out in the room (because bipolar) will spring for real veneer?

 

[MarkS]

My DefTechs were covered in black cloth ... totally fine with me

 

[jhaider]

My DefTechs were covered in black cloth ... totally fine with me

Were they five figures?

 

[MarkS]

Haha, no!

 

[Floyd Toole]

What's perplexing to me about the Axiom design is the dual tweeters and midranges on each side (front and back). Vertical directivity must have some pretty bad lobing.

This is an interesting point.

Most loudspeakers are vertical arrays, with varying degrees of "misbehaviour" in vertical off-axis performance - it has always been so. Fortunately it is the direct sound that is mostly responsible for our perception of sound quality, and equally fortunate that off-axis sounds radiate in multiple directions simultaneously and reach our ears as a complex bundle of energy - not isolated "rays" of sound exhibiting interference. Spatial and temporal averaging of many reflections attenuates the audible features of individual contributions, and an essentially omnidirectional loudspeaker generates an abundant supply of reflections.

In the spinorama data one can estimate the overall effects of off-axis radiations in the early-reflections and sound power curves, and they seem to convey information that parallels our perceptions.

It remains a fact that co-axial drivers, in spite of their logical advantages are not unique in being able to deliver high sound quality as judged by our hearing systems.

In the Axiom example it is my understanding that they conducted extensive blind evaluations and concluded that the anticipated interference was not a problem and that increased power-handling and reduced distortion of twin drivers was advantageous. I had no involvement in those tests, but can believe in the results. If the goal is high sound levels, it is a physical fact that a single 1-inch tweeter might exhibit limitations, as will any "small" driver. Horns/waveguides are an alternative method of increasing power-output capability, but they introduce other trade-offs and omni-directional dispersion is not one of their strengths.

Loudspeakers in small rooms are far from ideal communicators of sound energy to our eardrums, but the music survives . . .

 

[RickS]

As for bipole/omni loudspeakers, I owned a pair of Mirage M1s, reported in Section 7.4.6 in the 3rd edition of my book. For my purposes then (about 1990), they were very rewarding, but seeing the measurements I expect the Axiom would be even better sounding and have considerably more output capability.

As much as you enjoyed your Mirage speakers, using currently available products, would you deploy multichannel in that same room or a different approach?

 

[Floyd Toole]

As much as you enjoyed your Mirage speakers, using currently available products, would you deploy multichannel in that same room or a different approach?

Good question. It was a large, very diffuse room, and for some programs it was just unique and quite wonderful. If I still had that house I would likely have upgraded to more powerful dipole/omnis. I had a multichannel system in my home theater, this was our living/dining room and didn't deserve to be visually corrupted to audio gear. Even I have limits

 

[Floyd Toole]

I’m not sure why they bother with a ten thousand dollar speaker pair wrapped in fake wood look vinyl.

Not long ago I was being toured around a loudspeaker factory and my guide, the owner, showed me examples of real and fake finishes - to me they were visually indistinguishable - making the point how peculiar it is that people are willing to pay more for the real thing, when it has nothing to do with the sound. But they offer both. Modern fakes are not like the old days. I have real veneer loudspeakers that have a high-gloss finish and frankly they look more like plastic than wood. And black piano finish is paint, and it is widely respected in high end loudspeakers - but it has a connection to grand pianos.

I have heard more than a few real wood, even solid with hand-rubbed finishes, loudspeakers that sounded anything but good, and cost five figures. It's a choice - caveat emptor.

 

[MarkS]

In the Axiom example it is my understanding that they conducted extensive blind evaluations and concluded that the anticipated interference was not a problem and that increased power-handling and reduced distortion of twin drivers was advantageous. I had no involvement in those tests, but can believe in the results. If the goal is high sound levels, it is a physical fact that a single 1-inch tweeter might exhibit limitations, as will any "small" driver.

Well maybe, but I'm not aware of any other engineering-focused manufacturer (Revel, KEF, Genelec, etc) that has reached the same conclusion. All have top-of-the-line speakers using a single 1-inch (or smaller) dome tweeter.

A related question: what is Revel's theory of tweeter height? It seems to me that the tweeter (which beams the most) should be at nominal ear height for a seated listener. KEF seems to agree. But Revel always puts the tweeter at the top. Why?

 

[Floyd Toole]

Well maybe, but I'm not aware of any other engineering-focused manufacturer (Revel, KEF, Genelec, etc) that has reached the same conclusion. All have top-of-the-line speakers using a single 1-inch (or smaller) dome tweeter.

A related question: what is Revel's theory of tweeter height? It seems to me that the tweeter (which beams the most) should be at nominal ear height for a seated listener. KEF seems to agree. But Revel always puts the tweeter at the top. Why?

All these brands have horn/waveguide loaded tweeters that greatly benefits their efficiency just above crossover, which is where the problems arise: a small diaphragm trying to match the output of a larger midrange. For truly high sound levels a system like the JBL Pro M2, which is superb in terms of sound quality and can cause instant hearing loss if pushed. I would have had them in my theater if they had more eye appeal.

As for Revel's choice of tweeter height, I wasn't asked for an opinion. Frankly with the on-axis and listening window curves as close as they are one would need to be quite far off axis before it would make an audible difference. I had a pair of Revel Salon 2s in my home theater in California, and you can see how I treated them in this photo - the tweeters were exactly at ear level , and there was no problem with a floor bounce. A drop down screen filled the space between for movies. Actually the motivation was to keep the right channel loudspeaker from being fried by the fireplace. It sounded superb with the mids elevated, and I have repeated it in my present scaled down system. I realized that I appreciated looking slightly up at the orchestra - from the expensive seats.

 

[Duke]

I realized that I appreciated looking slightly up at the orchestra - from the expensive seats.

Ha! I hadn't thought of it that way!

A forthcoming speaker design I'm involved with will have the tweeter somewhat above ear height, and I will pass your "from the expensive seats" insight along to the Ministry of Propaganda. (While not an omni, it is bi-directional, so kinda sorta related to the thread topic.)

Thanks!

 

[MarkS]

I had a pair of Revel Salon 2s in my home theater in California, and you can see how I treated them in this photo - the tweeters were exactly at ear level , and there was no problem with a floor bounce.

Brilliant! You must have had some mighty sturdy cabinets there ...