Omnidirectional speakers. The future?

Some thoughts:

>All speakers bounce sound around the room, in varying ways and to varying degrees, and that includes so-called 'point-source' monopoles. We need to be careful to properly distinguish among our terms: point-source, line-source, limited-dispersion, wide-dispersion, mono-, di-, bi-, and 'omni'-polar radiators, etc.

>No speaker is truly a point source, and neither is any microphone (and many do not try to be). A point source is a theoretical construct and cannot be achieved, only imperfectly simulated. But in theory, a true point source would be omnipolar. However, whether this would actually represent some kind of ideal receiving or radiation pattern is not necessarily a given, although it is often casually portrayed that way.

>The ear/brain does not function as a strict analog to a microphone. For one thing, the ear/brain can distinguish between a lot of the direct and reflected sound. What you hear in your listening chair is not what a microphone would record situated in the same spot.

>By the same token, the recording process is profoundly inadequate to capture what a person at the original event might hear.

>No matter what type of microphone or speaker is employed, we never even get within drive-by distance of the ballpark regarding a symmetrically complementary encode/decode record/playback process. The relationship is asymmetrical, arbitrary, unknown, and in practical terms unknowable.

>By the same token, even if the speakers could somehow function as a precise inverse of the recording microphones, since the listening room acoustics will always be an arbitrary imposition overtop of what can be captured of the performance space environment, we must acknowledge the incongruity in promulgating both that the speakers should mimic the behavior of the mics on one hand, and yet that those same speakers should attempt to eliminate or reduce the influence of the listening room acoustics on the other. You cannot really do either one very well, but you most certainly cannot even begin to do both simultaneously. (And arguments going to the supposed ability of either speakers or mics to somehow embody the physical properties of either instruments or singers is hardly worth commenting on, so fundamentally misguided is the idea.)

>We cannot lump together various di-, bi-, or 'omni'-directional speaker designs in rhetorical opposition to 'monopolar' or 'point-source' designs. The most popular variety of non-monopolar radiator is probably the dipolar planar kind, and this type of radiator can have less reflected sound than traditional dynamic/box speakers (not to mention bi- or omni-polars), due to its simulated line-source behavior limiting floor and ceiling reflections, and its 'figure-8' side-cancellation behavior limiting sidewall reflections, while the remaining front and rear wall reflections may be easier to treat without 'overdeadening' the entire room.

>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).

>While limited-dispersion loudspeakers may represent one kind of virtue for obtaining accurate home playback, they can only do so for a single listener in a single listening spot. In the real world of homes and people, speakers having broad, even in-room power response will often be more practically enjoyable.

>The advantages of planar speakers are not solely defined by their radiation patterns; there is also the issue of eliminating box enclosure distortions. In the case of full-range electrostatic panels, there is the elimination of crossovers and multiple, frequency-divided drivers. You pick your poison - there is no one perfect solution.

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.

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