omnidirectional loudspeakers = best design available

[goat76]

For isolated studio booths with total dampening and very close mics, I'm sure Omnidirectional speakers would do better than directional ones in creating natural room reverb.

For normal recordings where there is some ambience mixed in, you're just coloring it now, just like if you built a speaker out of instrument wood and made it resonate while playing cello pieces You now have too much resonance.

Yes, but you are missing one very important factor in the equation. You can never use two speakers for the reproduction of that recording because that will create two reverberating positions from a supposed single sound source (the vocalist). Only a mono speaker can come close to recreating a somewhat natural reverb from such a recording that is supposed to get help from the reverberation of your listening environment.

But of course, all that is completely the opposite of what most of us want to achieve, which is to hear the reproduction of the original musical event including the three-dimensionality reverberation of the space in the recording, and we need at least two speakers to make it possible to just come a bit closer achieving that.

In my opinion, we don't want to add anything more of our listening room’s reverberation than necessary, just enough to hide the shortcomings of the stereo reproduction and to add some envelopment to the (hopefully dominating) perceived stereo illusion. Most of the added effects beyond that will most likely just “blur” the perceived sound of the stereo recording, which is truly the only thing that contains the stereo illusion of the recorded three-dimensional space we want to hear.

Room treatment is very important, but just the right amount to minimize the “bad” effects of the listening environment.

 

[stevenswall]

Yes, but you are missing one very important factor in the equation. You can never use two speakers for the reproduction of that recording because that will create two reverberating positions from a supposed single sound source (the vocalist). Only a mono speaker can come close to recreating a somewhat natural reverb from such a recording that is supposed to get help from the reverberation of your listening environment.

But of course, all that is completely the opposite of what most of us want to achieve, which is to hear the reproduction of the original musical event including the three-dimensionality reverberation of the space in the recording, and we need at least two speakers to make it possible to just come a bit closer achieving that.

In my opinion, we don't want to add anything more of our listening room’s reverberation than necessary, just enough to hide the shortcomings of the stereo reproduction and to add some envelopment to the (hopefully dominating) perceived stereo illusion. Most of the added effects beyond that will most likely just “blur” the perceived sound of the stereo recording, which is truly the only thing that contains the stereo illusion of the recorded three-dimensional space we want to hear.

Room treatment is very important, but just the right amount to minimize the “bad” effects of the listening environment.

The music is made with that in mind when in the studio... The "phantom center" places the vocalist in the middle. Yes, you can also master music to have a center channel which could be a mono vocalist track.

Most music doesn't seem to be a traditional "music event." The piece was never performed as you hear it. Even if it was, you're still reliant on the engineer creating it with omni speakers in mind, or stereo speakers. Most of the time this is directional stereo speakers and you're compromising further going with omnis.

Seems like you might like something like the BACCH SP that can help you get a cleaner stereo image that doesn't seem as blurred.

BACCH-SP | Theoretica Applied Physics

www.theoretica.us

 

[Floyd Toole]

Thanks for this. Just a follow up; the stereo errors (Shirley et al.), eg the 2 kHz dip is enhanced in anechoic conditions vs reflective environment. Do you think the same is the case for near-field monitors - and if so, should that affect the on- or off-axis ”target” for a near-field vs far-field speaker?

The dip will be most pronounced when listeners are in a dominant direct sound field, as in near-field listening. Reflected sounds help fill in the hole, as Shirley et al. found. It is a non-minimum-phase phenomenon and therefore cannot be "corrected" by normal minimum-phase EQ. Since the dip exists only for the listener in the sweet spot correcting the dip with an EQ bump means that everybody else in the room hears an annoying bump. Probably not a good idea.

 

[Floyd Toole]

You could include Karlson (Sonab) speakers to that list.

I visited Stig Carlsson at his home in Stockholm. His loudspeakers were called "Ortho-Directional OD)" and they sprayed sound in many directions, but the principal goal was to stabilize the stereo image over an expanded listening area by tailoring the shape of the direct/early sound radiation. They were certainly not omnidirectional. I discuss this on p.404 in the 3rd edition of my book.

 

[Floyd Toole]

They really don’t need to be large…because there are 4.

Yes, there is a substantial efficiency gain when using multiple subs. Many people end up with more sound power than they actually need. I'll take four modest subs over the single most grandiose sub any day. In addition, there are some clever compact designs out there using vibration cancelling designs - good for those in multiple dwellings, as I will be sometime next year. Paradigm is one, and Sonos another - there may be more. In my case, moving into a "luxury condominium" my scaled down media room and limited maximum sound level (a good neighbor policy) should be well served by four such loudspeakers. I will be employing a trick I learned many years ago - near-field subwoofing - place the subs close to the listeners. That will let us hear decent bass quality and levels with less energizing of the entire room. The mechanical vibration cancellation won't hurt sound transmission to adjacent properties - floors are notoriously difficult to isolate without access to the floor below.

I am willingly downsizing and changing my life style - at age 84 it seems reasonable - but there are many, many people who have no choice. Methinks there is a product category that needs more attention.

Meanwhile, while I am still in my detached home with my 7.4.6 system I am enjoying last flings with a 10 ft screen and my four not-large 12-inch closed box subs that can lift me out of my seat.

 

[Floyd Toole]

Hi Dr. Toole,

When you talk about “off-axis”, do you mean the horizontal only, or the vertical is of the same importance?
Does coaxial really have advantages over traditional two-way?

Our ears are in the horizontal plane, so our hearing is very different vertically and horizontally. Horizontal absolutely dominates the "spatial " domain. I know of no persuasive reason why coaxial designs should be "inherently" superior. There are some advantages to be sure, but with the tweeter at the bottom of a woofer/midrange there are also some disadvantages - very wide dispersion being one. That said, I cannot say that good sound at a normal listening distance in a normally reflective room is in any way compromised. Both are viable designs.

 

[restorer-john]

His loudspeakers were called "Ortho-Directional OD)" and they sprayed sound in many directions, but the principal goal was to stabilize the stereo image over an expanded listening area by tailoring the shape of the direct/early sound radiation.

His 'principal goal' seemed to be to throw as many drivers as he could on the top of a speaker in various pretty patterns with the vain hope something worked out.

Every time I saw a pair, there seemed to be more drivers on each successive model. The model below has 12 little AlNiCo 'tweeters' (cones, weren't they?)

Internet pic

My recollection of the sound of several I heard was not good. But that was the 70s. What did you think?

 

[LTig]

I will be employing a trick I learned many years ago - near-field subwoofing - place the subs close to the listeners. That will let us hear decent bass quality and levels with less energizing of the entire room. The mechanical vibration cancellation won't hurt sound transmission to adjacent properties - floors are notoriously difficult to isolate without access to the floor below.

Another possibility is a special sound shaker chair. I once played a demo drum set with a Porter & Davies drum chair which features a built in shaker fed by the BC2 amp. It works trough bone conduction and bass was really good. If they ever make a standard sofa or similar with this shaker embedded I'm probably going to buy it on the spot.

 

[restorer-john]

I am willingly downsizing and changing my life style - at age 84 it seems reasonable - but there are many, many people who have no choice. Methinks there is a product category that needs more attention.

Meanwhile, while I am still in my detached home with my 7.4.6 system I am enjoying last flings with a 10 ft screen and my four not-large 12-inch closed box subs that can lift me out of my seat.

Well, if anyone can put an audiophile and renowned acoustics expert in a condominium, surrounded by neighbours on all sides and not get noise complaints, it would be you.

Maybe document the journey for another book. Could be a best seller.

 

[Els]

His 'principal goal' seemed to be to throw as many drivers as he could on the top of a speaker in various pretty patterns with the vain hope something worked out.

Every time I saw a pair, there seemed to be more drivers on each successive model. The model below has 12 little AlNiCo 'tweeters' (cones, weren't they?)

Internet pic
View attachment 251618

My recollection of the sound of several I heard was not good. But that was the 70s. What did you think?

I had the OA 14 which had a few less tweeters, the model pictured was very rare, I would have bought a pair if found at the right price. Very hit and miss as far as room integration but could sound very concert like and impressive in the right room. Also excellent mid-century design. I have always called these omni directional but stand corrected by Mr. Tool. Carlsson was a great innovator and a very credible engineer and dedicated speaker designer.

 

[mhardy6647]

His 'principal goal' seemed to be to throw as many drivers as he could on the top of a speaker in various pretty patterns with the vain hope something worked out.

Every time I saw a pair, there seemed to be more drivers on each successive model. The model below has 12 little AlNiCo 'tweeters' (cones, weren't they?)

Internet pic
View attachment 251618

My recollection of the sound of several I heard was not good. But that was the 70s. What did you think?

Peerless cones, I do believe.
Yes, some of his loudspeakers were pretty Byzantine. The relatively (!) simple & inexpensive Sonab Carlsson loudspeakers I remember listening to at Soundscape in Baltimore, MD (a long time ago) sounded good to me.

... and not to be confused with Karlson loudspeakers.

(a photo of my rather limited Karlson kollection )

 

[Els]

Perhaps the ones that Amar Bose actually claimed to design, the 901's? That seemingly only worked right when hung from a ceiling at a certain distance from both the ceiling and the wall? I heard that Amar (Mr. Reflective sound at the time) saw Paul Klipsch at a an electronics show and yelled to the wall "Hello, Paul" and that Paul (Mr. direct sound all his life) turned directly facing Amar, cupped his hands around his mouth and yelled "Hello Amar".

That about sums it up. Remember concert hall sound is 20% direct and 80% reflective; Also point source is ONE microphone in reverse.

 

[Els]

I don't know. Maybe a large dipole or some CBTs. Or a multichannel upmixing system.

Or huge soffit mounted mains. I wouldn't rule out monitors as impractical

In any case I heard the smaller MBLs in a really small room at a show an they sounded nice. I can't think of an optimal environment for them. I'd have to try some at the ol' homebase before forming an opinion.

Sounded nice!!, at that price it must be a colossal failure.

 

[goat76]

The music is made with that in mind when in the studio... The "phantom center" places the vocalist in the middle. Yes, you can also master music to have a center channel which could be a mono vocalist track.

Most music doesn't seem to be a traditional "music event." The piece was never performed as you hear it. Even if it was, you're still reliant on the engineer creating it with omni speakers in mind, or stereo speakers. Most of the time this is directional stereo speakers and you're compromising further going with omnis.

Seems like you might like something like the BACCH SP that can help you get a cleaner stereo image that doesn't seem as blurred.

BACCH-SP | Theoretica Applied Physics

www.theoretica.us

I know perfectly well how a phantom center is created, as I have mixed my music formany years.

Just because our hearing is tricked by the stereo illusion to hear the phantom center as if it is a real sound source placed in a central position between the stereo speakers, the actual sound still originates from the physical positions of the two speakers in the stereo setup.
But when it comes to the room reflections, that phantom will no longer be treated as a single sound source point by the room, on the contrary, it will be generated by the actual two physical positions of the two loudspeakers.



So back to your initial idea...

You were talking about a dry recording of a single vocalist, and the spatial sound was supposed to be generated by the room reflections of the listening room, right?

If those reflections will sound completely natural as if they were generated from a single source (the vocalist ), a single mono speaker must be used, not two because they will generate room reflections from two sources.

Do you see the problem now?

 

[DanielT]

His 'principal goal' seemed to be to throw as many drivers as he could on the top of a speaker in various pretty patterns with the vain hope something worked out.

Every time I saw a pair, there seemed to be more drivers on each successive model. The model below has 12 little AlNiCo 'tweeters' (cones, weren't they?)

Internet pic
View attachment 251618

My recollection of the sound of several I heard was not good. But that was the 70s. What did you think?

An exception to Carlsson's models. In addition, his models became more direct-aimed/sounding over the years. Here his last creation OA 52.2 from 1996:

The model before OA 52.2 was called OA 51 and looked like this:

 

[DanielT]

Yes, there is a substantial efficiency gain when using multiple subs. Many people end up with more sound power than they actually need. I'll take four modest subs over the single most grandiose sub any day. In addition, there are some clever compact designs out there using vibration cancelling designs - good for those in multiple dwellings, as I will be sometime next year. Paradigm is one, and Sonos another - there may be more. In my case, moving into a "luxury condominium" my scaled down media room and limited maximum sound level (a good neighbor policy) should be well served by four such loudspeakers. I will be employing a trick I learned many years ago - near-field subwoofing - place the subs close to the listeners. That will let us hear decent bass quality and levels with less energizing of the entire room. The mechanical vibration cancellation won't hurt sound transmission to adjacent properties - floors are notoriously difficult to isolate without access to the floor below.

I am willingly downsizing and changing my life style - at age 84 it seems reasonable - but there are many, many people who have no choice. Methinks there is a product category that needs more attention.

Meanwhile, while I am still in my detached home with my 7.4.6 system I am enjoying last flings with a 10 ft screen and my four not-large 12-inch closed box subs that can lift me out of my seat.

Smart, with multiple subwoofers. I completely agree with that.

Too much bass, "more sound power than they actually need". Then I will think about extreme bass solutions for cars. Something that apparently appeals to many young people. We've all heard of those bass in car (they are heard in the distance). Sounds loud as hell and bass shakes the whole car and creates a heavily distorted bass.Lots of bass but hardly good bass. Or as we older people might say about it, it's a type of Hades, he he. But let the youth have fun, I say.

Who knows, they might need these extreme bass solutions to impress friends, to impress girls.

See attached picture, a search on Youtube: Extreme bass in car
There are tons of such videos.

 

[Thomas_A]

The dip will be most pronounced when listeners are in a dominant direct sound field, as in near-field listening. Reflected sounds help fill in the hole, as Shirley et al. found. It is a non-minimum-phase phenomenon and therefore cannot be "corrected" by normal minimum-phase EQ. Since the dip exists only for the listener in the sweet spot correcting the dip with an EQ bump means that everybody else in the room hears an annoying bump. Probably not a good idea.

In near-field there is usuallly only one listener. And I think you can adapt to a certain extent if you 1) provide a wider dispersion 2) making small corrections such as +1 dB at 1-2 kHz (especially to increase dispersed power) followed by -1 dB at 3-4 kHz. And in general a power dip in the 2 kHz range in the room response as shown in some of the graphs you provided should not help, rather worsen the problem. Rather it should be ”flat”and followed by a smallee dip 3-4 kHz.

 

[EJ3]

But the 901s weren't cubes.

They were designed to be listened to on-axis, for some weird backwards definition of axis.

Man, now I want to get a pair just for the funkiness.

A friend of mine has a pair of the 901's specifically located and a pair of Cerwin Vegas (do not know which ones) that also seem to be specifically located) When all 4 are operating together, the sound is subjectively pretty good.

 

[EJ3]

https://www.linkwitzlab.com/LXmini/Introduction.htm

If you find some measurements for Beolab 5 (frequency response 0-180 degrees) i'll tell you if it is omni or not.

10-4, thanks

 

[stevenswall]

Do you see the problem now?

I don't recall disagreeing that an omni speaker would sound natural for a dry recording in mono for a vocalist.

The problem seems to be that music isn't made to work with the system you'd like, and if the vocalist does only have one channel then it's likely Atmos and that wasn't mastered with omnidirectional speakers either so the solution is still to use regular speakers.

If one had a room with better diffusion and absorption that they preferred to a studio and could access and "mix" their own mono stuff however they preferred, I could see that being ideal sound wise for something sounding natural. Too many issues for me.