Omnidirectional speakers. The future?


I have been interested in hi-fi for about 25 years. I usually get the hankering to buy something if it knocks my socks off. Like most I started with a pair of box speakers. Then I heard a pair of Magnepans and was instantly hooked on planars. The next sock knocker was a pair of Soundlabs. I saved until I could afford a pair of Millenium 2's. Sock knocker number 3 was a pair of Shahinian Diapasons (Omnidirectional radiators utilizing multiple conventional drivers pointed in four directions). These sounded as much like real music as anything I had ever heard.
Duke from Audiokinesis seems to be onto the importance of loudspeaker radiation patterns. I don't see alot of other posts about the subject.
Sock knocker number four was a pair of Quad 988's. But wait, I'm back to planars. Or am I? It seems the Quads emmulate a point source by utilizing time delay in concentric rings in the diaphragms. At low volumes, the Quads might be better than my Shahinians. Unfortunately they lack deep bass and extreme dynamics so the Shahinians are still my # 1 choice. And what about the highly acclaimed (and rightly so) Soundlabs. These planars are actually constructed on a radius.
I agree with Richard Shahinian. Sound waves in nature propagate in a polyradial trajectory from their point of source. So then doesn't it seem logical that a loudspeaker should try to emmulate nature?

holzhauer
Hi Guys,

Thanks for the responses. As subjective as the listening experience is, it always boiled down to perception and preferences, so my "opinions" are simply that.

To answer a few of the questions:

Holzhauer asks:

"Real musical instruments have "wide dispersion" and "spray" music all over the room. Isn't it possible that a speaker that mimics this might come closer to the real thing?"++

John Casler (allow me to use my name) writes:

It seems that the confusion arrises when you try to apply what happens in the "recording venue" and apply it to your room.

The answer is "no". In a stereo system the two channels are mixed to "re-create" the original from TWO sources not "create" a performance "using" your room.

Re-creating the sound from two sources, is like a projection TV, blending two or three guns to re-assemble a picture. Adding room large amount of reflected room light to that recreation would have similar deliterious effects.

And the confusion about wide dispersion is that you can somehow hear all of it. You cannot and do not. You hear only what arrives at your ears. So any dispersion beyond the size of your ear will only serve to bounce all over the place and have effect to the "real recorded venue ambience" which then is degraded by it.

Holzhauer wrote:

But I'll bet a dollar thata majority of listeners would prefer the sound of a good pair of omnis over a monitor setup.

John Casler writes:

While that may be, it doesn't change the physics and psychoacoustic involved. KodaChrome and FujiColor look better than real life sometimes. Nothing wrong with that.

Holzhauer wrote:

Amar Bose really was on to something. Most "audiophiles" laugh about him and discount his work. I think they are making a big mistake.

John Casler writes:

While his research was true (measuring direct to reflected sound in venues) his reasoning was flawed. You cannot recreate the original event (or a close proximity) by overlaying another set of ambient signatures from close in reflections.

AudioKinisis wrote:

That sounds very convincing, but if it is true, then why are we not all listening to headphones? With absolutely zero degrading room interactions, wouldn't headphones be the holy grail - the "poor man's anechoic chamber", if you will?

John Casler writes:

You are partially correct, the sonic purity of headphones "is" sans room interaction.

But.... The problem is it doesn't offer the correct spatial relationships to the ear brain. That is it doesn't give you the sense of the performance happening in front of you, but "within" you.

While the absence of room is accurate, the way the pinna gathers the directional cues for a soundstage presentation isn't. The sound actually has to come from "in front of the ear", and have the correct angular incidence, for soundstage and image creation.

AudioKinisis wrote:

Let me start out by noting that recordings are made to be listened to in a reverberant environment.

John Casler writes:

Live recordings "are not made" to be listened to in a reverberant environment. Not sure where you got that idea.

No recording engineer knows what exact "environment" or system their work will be played back in. And many studios and mixing rooms are "acoustically treated" to a very high degree.

AudioKinisis wrote:

the loudspeaker/room combination must be doing something good to the reproduced sound, else we'd all be saving up for a pair of Stax headphones.

John Casler writes:

I was very careful not to say that reflective set ups don't sound good. Some sound beautiful. I simply said you cannot re-create the sonic event and venue, by overlaying another completely different set of environmental acoustics to it. It is simple psychoacoustics.

AudioKinisis wrote:

"Spaciousness is created by a large number of laterally arriving sound waves which are preferably delayed from the direct sound by more than 10ms. Only the reverberant field can possess this characteristic... In order to have the feeling of spaciousness, one must first be in a room location with a reasonably high reverberation level relative to the direct sound level." - Dr. Earl Geddes on sound perception in small rooms. So when it comes to spaciousness, reverberant energy is our friend.

John Casler writes:

I don't know what this was written for, but it is true as far as the recording venue, and false relating to the reproduction environment.

The recorded "ambience" carried on the software is subtle and delicate. Imagine the venue is say a Church that is 75' x 75'. The sonic ambience recorded is based on the delicate reflections of the instruments and performers in that space.

Then you use a highly dispersive and reflective system in your room and spray all those signals around a 20' x 30' room and harvest yet another set of ambient and reflective signals.

You actually think it will sound the same as the original?

AudioKinisis wrote:

The rich, lively sound we so enjoy in a good concert hall (and find lacking at an open-air performance) is largely the product of a highly diffuse, relatively late-arriving and slowly-decaying reverberant field (Pisha & Bilello on live end/dead end room techniques).

So reverberant energy does some good things, and some bad things. Generally speaking, strong, distinct early-arriving reflections are likely to do more harm than good, while late-arriving, diffuse reverberant energy is almost always beneficial in a home listening room.

John Casler writes:

Don't confuse the room interactions in the "Concert Hall" with the interactions in your listening environment. They are two totally different things. This is where I think much of the confusion starts.

Again it is like saying "lighting on a movie set is good" so maybe we should add some more lighting in our HT. It doesn't work that way.

AudioKinisis wrote:

So while it makes intuitive sense to say that anything the room does to the sound is degradation, I'd argue that the room does some very good things to the sound: It adds spaciousness and timral richness and liveliness, hopefully with minimal detriment to image localization. Indeed when it comes to votes cast with our wallets, I think most of us have voted in favor of at least some room interaction.

John Casler writes:

The argument that room interaction does some "good" things goes back to subjective preference.

In my limited room interaction system, I would counter that I hear the real (or closer to) "spaciousness and timral richness and liveliness", and my images, original ambience and soundstage it breathtaking.

My point "was" and "is" that room created sound does not give you the original performance and its sonic environment.

Zaikesman wrote

An anacheoic chamber will not make a good listening environment primarily because recordings are not mixed and mastered by people operating in anacheoic conditions, and well-designed stereo speakers will take into account the fact that they will not be used in anacheoic conditions. If recordings and speakers *were* made to be listened to in anacheoic chambers, we would perceive the inadequacy of stereo to provide convincing reproduction and prefer some sort of well-implemented scheme involving more channels, coming from more directions (with the artificial exception of recordings whose original performance space was an anacheoic chamber as well).

John Casler writes:

Thanks for your thoughts Zaikesman. They are well thought out.

Those who state that live recordings will not sound "real" in an anechoic environment have not listened (properly) in that environment.

In fact, just walking into such a chamber and "not hearing" the room is startling to some. I would doubt that many have actually done any serious nearfeild listening in such.

I have.

For those who want to experiment see below.

Just take your best "live" recording and place your system "outdoors" (not today if you live in the Midwest/Northeast) and sit as nearfeild as your system will allow and be prepared to be amazed. It may be the first time many have heard a recording, so close to the original, without hearing their room colorations.

Zaikesman wrote

I could probably go on, but I'll lay out for now. For the record, I use dynamic, box, monopolar, multi-point speakers intended to have relatively broad, even dispersion and low difraction, and to sum with minumum phase and time distortion at the optimal listening position (they are Thiels). This approach, like all others, has its advantages (some of them purely practical, some of them quite possibly purely theoretical) and disadvantages - and also like all others, fails in the end to achieve a realistically convincing portrayal of the actual thing.

John Casler writes:

You state it well. In the end it is just a goal to "reduce" all the elements that can "degrade" the original sonic.

Your, "low difraction, and to sum with minumum phase and time distortion at the optimal listening position", speaker qualities, are all focused at arriving at a more accurate recreation.

Each component, cable, tube, or whatever is generally used to either feed a preference, or achieve accuracy to the orignal perfromance.

My original premise is still the same, and room created "distortion" (and it IS a distortion of the orignal signal) is some of the easiest to treat, but as you said, impossible to eliminate.

Good discussion, and thanks to all for their thoughts.
John, I'll give your VMPS 40's a listen if you'll give my Shahinians a chance. A few of my audio heroes love the Dali Megalines which might share some similarities with the speakers you sell. You don't happen to be in the Chicago area?
Sorry I'm in LA, but there are a couple dealers in Chicago and Wisc.

The reason I sell RM40s (since you brought it up) is their limited dispersion.

But let me continue to say, I love the sound of many speakers, systems, and rooms. I trust no one felt I was "downing" the sound of any speaker.

I might further comment that many speakers, well set up, can sound marvelous.

Haven't heard any Shahinians lately to bad your not closer (I'm in LA, CA)I'd love to hear them, and what they can do. I meant to drop in on them at CES, but time gets away from you there.

All the best,
Hi Summitav a.k.a. John Casler,

Thanks for taking the time to reply. I'm not going to try to rebut your individual points, as I think we've both put sufficient effort into stating our positions.

However, since you dispute the quote I included, just for the record let me say that Dr. Earl Geddes is a long-time loudspeaker industry professional, author of numerous research papers and several books, wrote his doctoral thesis on small room acoustics, is probably the world's foremost authority on waveguides, holds seventeen patents with seven more pending, and recently gave a loudspeaker design seminar at ALMA in Las Vegas and will be doing so again in Europe this summer for the Audio Engineering Society convention there. I did not take his remarks out of context - he was referring to the reproduction of sound in a small room ("Premium Home Theater, Design & Construction", page 95). You might want to check out his website, www.gedlee.com - not because his website supports any of my points, but because he's on the frontier in many areas, such as refining our understanding of what kinds of distortion matter to the ear and what kinds don't.

By the way I have listened to my stereo outdoors (well, a stereo I used to have), and it did sound better than inside my room. Timbre was more natural, and imaging and clarity were much improved. But those speakers were poorly designed from a room interaction standpoint, and poorly setup within my room (zero attention paid to minimizing early reflections, for example). In all fairness I have not heard a genuinely high quality home stereo system outdoors - that would be an interesting experiment that I hope to try one day. I have turned my living room into a virtual padded cell by means of panels of thick open-cell foam on frames leaning against the walls, and I did not like the results at all - very precise, but lifeless. In my opinion, the best in-room reproduction I have heard has been from setups where (among other things) care has been taken to establish the kind of late-arriving, well-energized, diffuse reverberant field I've described above.

Duke
Summitav wrote: "Those who state that live recordings will not sound 'real' in an anechoic environment have not listened (properly) in that environment."

You are quite correct that I haven't had the opportunity to listen to anything, much less a good stereo, inside of an anechoic chamber. That's a chance that's tough to come by for most of us. I have no doubt that the experience would be revelatory in many ways. (I have listened, and worked, in studio control rooms where recording, mixing and mastering are done, know that these are not anechoic environments but rather controlled environments, and have prefered using ones - and gotten better results - where the monitoring options are not limited to just the nearfield.)

But I'll still stick by my contentions A) that a stereo system would sound best in an anechoic chamber if the speakers (and the recordings played through them) were designed with that as their intended environment, and B) that a well-implemented multi-channel scheme would sound more naturally convincing in that environment than would stereo (there's nothing sacrosanct in theory about limiting ourselves to 2 channels as some sort of ideal paradigm for sound reproduction, it's just much simpler to do well than a higher number of channels).

Those statements imply some corollaries:

>That speakers intended for home use will sound better if they are not designed solely on the basis of anechoic measurements, but take into account more typical listening room acoustics.

>That a well-implemented multi-channel scheme could also sound better than stereo in the home, but also that this would not only be highly dependent on the efficacy of the recording process used, but on closely controlling things like dispersion and room acoustics as well. Or in other words, the room properties, or distortions, that can actually make 1- or 2-channel reproduction go down more easily as a subjective matter, will become more problematic as we continue to add channels and speakers. The more we do to try and supply some semblence of the 'real' recorded performance space acoustic, the less we will be able to tolerate overlaying the arbitrary and unrelated listening room acoustic as a kind of a ameliorative substitute.