Omnidirectional speakers. The future?

Sean...This is a truly huge pie shaped shed, but its acoustics have been taylored by various absorbing and reflective panels. Other than these panels, all surfaces are highly reflective wood and iron trusses. Of course the sound is constrained between the ceiling, about 60 feet, and the floor. There are no sidewalls from ground level to about 30 feet. Suspended over the stage there is a constelation of curved panels much like a band "shell". I think that the sound has an easy trip over the heads of all the people to the panels at the back, and then down to the last few rows. This is a most unusual performing space but I think that the proportion of reflected sound is very high, and just about 100 percent in those last rows. And it still sounds pretty good.

El: I don't doubt your observation. The one point that i would make would be in question form to you. That is, "Is just one or both of the principles stated above coming into play in the last row?". Sean
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Sean...Come to Tanglewood and listen for yourself. The "last row" effect is well known.

El: As sound travels further, it loses intensity. This is true whether it is a directly radiated signal or that of a reflected signal. The only time that one encounters increased intensity at a greater distance from the originating source would be in the following situation. The first is when one is stationed in an area where a node occurs in the listening environment. The other example is at the far end of some type of acoustic coupler i.e. the increased output at the far end of a horn throat. Otherwise, the shortest, most direct path will have the greatest acoustic intensity possible, especially at mid to high frequencies. Sean
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Sean...with regard to percentage of reflected sound...I used to work as an usher (unpaid) at the Tanglewood summer music festival, and so I learned something of the acoustics of the huge shed in which the BSO performs.
Seats up front can hear well. Seats slightly further back, but still in the higher price range don't hear well at all. The very last few rows, way at the back, hear well again: almost as well as those expensive up-front seats. The reason is reflective panels that are suspended about 40 feet above and 30 feet behind the last row, and angled down. Reflected sound can be loud.

Billhound, I see you have taken the time to consider both sides of the omni vs. conventional loudspeakers. If I had never heard a properly executed set of omnis I think I would have been convinced by the arguments of Opalchip and Summitav. Their logic makes a lot of sense.
Duke makes a lot of sense also. If delayed reflections help us perceive the music to be more realistic, then omnis have a leg up in the way they intentionally send music in various routes that will no doubt delay arrival time at the ear.
I found Shahinians in a strange way. About 15 years ago I set out to buy the best stereo money could buy. It was a goal that I had kept my sites on through college and I was bound and determined to do it. At the time, the Wilson Watt Puppies were all the rave. I found a shop in Niles (Chicago suburb) called Rosine Audio and arranged an audition. The speakers sounded great. (All Spectral electronics didn't hurt the sound either.
The next day I was talking to one of Larry Rosines sales people and I asked him what speakers he likes to listen to when the customers are gone. He immediately said Shahinian. He had the Shahinioan Arcs avaiable but no Diapasons. I eventually got to hear the Diapasons. I can tell you with no amount uf uncertainty that they walked all over the Wilsons.
In my Quest, I listened to a lot of expensive speakers. The huge B&W 800's, large Thiel 7's, Martin Logan Statements, Avantegarde Uno, Duo and Trio, Magnepan MG20's, Pipe Dreams, ProAcs, Dynaudio, Meadowlark, Joseph Audio, Soundlab Electrostats and Quads. The Soundlabs, Quads and the Shahinians were the best of the bunch. As you can see, I ended up with the Shahinians.
With the Omnis I am free to move about the room. The music sounds great anywhere you sit or stand. The idea of sitting with my head in a vice to obtain perfect alignment all the while surrounded by an acoustically dead anechoic chamber so as to obtain the theoretical ideal of zero reflections doesn't appeal to me at all. I recall in listening to the Wilsons a very analytical experience. The speakers were revealing all the flaws in the recording yet not capturing the essence of the music. I'm not trying to offend those who enjoy the analytical experience. It's just not for me. The sound of the omnis is so real that it is just stunning at times. Never do these reflections conjer up thoughts of distortion. Only real live music.
It doesn't surprise me that Shahinians sound good outside. In a lot of ways, they are like four conventional box speakers placed back to back. In a non reflective environment, a majority of what is heard wil be the direct sound from the portion of the speaker pointing at you.
It's too bad Shahinian doesn't have any active dealers in the US. Like billhound, most people aren't going to purchase a speaker without hearing it first. Shahinians' European distributor goes to a lot of shows and has made the Shahinians immensely popular in Europe. For those willing to take a little risk, I suggest buying the Shahinian Obelisks used for $2000 or less. In that price range, you could unload them without getting hurt if you decided they weren't your cup of tea.

Thanks very much for your thoughts, guys.
My space is indeed houselike in scale- it is my live/work
space. I live in an open loft in what was at one time a
commercial building. Possibly something similar
to the factory-like space that Holzhauer describes in
Mr. Shahinian's set up. Unfortunately, Diapasons are
not in my budget. I wonder how one of their less pricey offerings might fair in an oversized space. Its a pity that Shahinians and other omni-like offerings are impossible to demo before purchase- I like to avoid expensive leaps of blind faith when I can.

I do not expect any speaker I might buy, omni or not, to energize my whole space. I just want to hear great music in a 'designated' listening area. Because of my flat out ignorance when it comes to the science of acoustics, I wasn't sure if that's a reasonable goal or not. Omnis intrigue me because I wonder if they could create this hypothetical 'sweet area' in my space as well, worse, or better than conventional designs.

My ignorant gut says there may be advantages to omnis in my situation since they are designed in part to depend on room interaction. While I will end up doing a few things in here to try take the edge off all the high reflectivity, I dont intend to invest time and money in a complete high end sound treatment, or carve up my space into rooms. So, since my envrionment will inevitably have some significant interaction with whatever sound system, why not go with speakers designed to interact with their environment in the first place? Hence my interest in omnis.

Audiokinesis provides a well reasoned and knowledgeble articulation of that idea, which was really only a hunch for me before I read his helpful post- thanks.

In trying to understand how omnis and omni-like speakers work, I find Holzhauer's report that the diapasons sound great outdoors counter intuitive. Since the system is designed to interact with its environment, I would have imagined that removing walls and ceilings, (i.e. setting them up outside), would actually make the speakers sound bad, or at least significantly different than the designer intended. Maybe I understand this stuff even less well than I think I do.

Many have pointed out that omni's cannot reproduce the actual sound of the recording due to simple physical law.
Again, while I have no training in acoustics, the reasoning sounds correct to me, and its great to have a peek into the actual science of it. As they point out, this does not necessarilly indicate that they sound "bad", unless one's goal is a strictly truthful representation of the recorded event. I know that's supposed to be a goal of hi-fi, but I don't fall into that camp, if for no other reasons than practicality and cost. Even in set ups where price is no object, I bet there is still acomodation made by the listener for the sonic 'white lies' that inevitably slip in through the door along with the strictly accurate sonic 'truths'. I'm more interested in a balance between euphoney, accuracey, and price.

In the end what sounds good is such a personal question, that I lament again the problem of not being able to demo most of these omnis up front. While a store demo wont tell how a speaker will sound at home, it will at least give a clue. That's one reason I'm arbitrarilly deciding not to consider horns. They might do the trick great, but they seem to be as difficult to find as omnis, and it would be nice to actually start listening to something soon!

Bose 901's are based on 11% direct vs 89% reflected sound. Unless one is standing completely off axis and slightly around a corner from where the performance is taking place, those ratios are highly unlikely to be anywhere near accurate during a live listening session. The fact that Bose based most of his findings on measurements taken while sitting underneath the overhang of balcony seats may explain at least a portion of his findings. Why someone would use that specific seating location to conduct those types of tests is beyond me though.

As far as binaural recordings go, i mentioned this type of presentation working phenomenally well with Omni's much earlier in this thread. I've commented on this type of recording technique over at AA in the Pro Asylum quite some time ago. When Alan Kafton of Audio Excellence / Audio Dharma cable cooking asked about various methods that could be used to record small ensembles in a nightclub, that was the first technique i told him to try. It is minimally intrusive in terms of set-up and operation and can provide a very natural presentation, both in terms of spatial cues and tonal balance.

As a side note, i used to use this technique when recording bands for "demo's". Not only is the sound "live" i.e. not nearly as manipulated as is done with dozens of mics and processing, it is also lower in distortion ( less microphone overload ) and much closer to what one would actually hear at a show. If a band can sound good on stage without a bunch of multi-track gimmicks, the talent scouts working for record companies know that they can be made to sound "even better" in a studio. The reason for that? They have all the knobs and gadgets required to "make magic happen". At least, so they think. A high quality binaural recording is pretty hard to match in terms of natural sonic qualities. The one major drawback is that it will not sound as "detailed" or "image specific" as an electronically manipulated presentation using dozens of up-close mic's and tons of bells and whistles in the recording chain.

As far as using the "true" Walsh type Ohm's in a huge room, i've never tried it. Their bass output may be up to the task, but they simply can't move enough air to fill the room with sound. That is, they are SPL challenged due to "warbling" i.e. highly audible amounts of Doppler distortion once you hit a certain volume level. With this type of design, there's no way around that problem. Sean
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Hi Guys, Just dropped in to see this thread still going.

Lot of interesting ideas floating around, but the concept of "dispersion" mimicking instrument size, or cone size making an instrument sound larger is slightly off the mark.

Must be a visual thing. That is, we are comparing it to how we "see" things.

That is not how recorded stereo sound works at all.

Recorded sound is more like a three gun projector that has three beams that have to be perfectly converged to form a visual image. In the case of stereo, it is two "sonic projecting guns" that have to be converged to form a sonic image for the ear brain.

It the "projectors guns" are diffused and dispersed, the visual image is blurry and washed out. If they are clear and focused, they form a highly resolved and detailed image on the screen.

Wide dispersion from a speaker does not have anything to do with the way you hear it unless your ears are 3 feet wide on each side of your head.

Spreading the sound out 90 degrees, 180 degrees or 360 degrees, will not cause it to sound like the real instrument since your ears only sample TWO "very small" samples. And that image is formed by sampling 2 signals that combine to make the image.

The illusion or "confusion" is related to perceiving that we somehow hear recorded sound from stereo, as we do a live event.

We don't.

In real life, we have millions of sound sources coming in from any and all angles. In stereo, we have 2. Trying to make (disperse) the 2 into that million is not only futile, but impossible.

This is an attempt to "disassemble" the two signals, by sending them all over the place to somehow be reassembled at you ear.

Taking these two samples and trying to make them disperse into some sonic spray, and expecting that this spray will then gel into a soundstage, won't happen.

Now don't get me wrong, it can sound beautiful, but it really won't do what most are thinking.

The Bose 901s developed by Dr Amar Bose in the late 60s, tried to perform this by firing all that info into a reflective surface (wall) and using that dispersion and about 17-22% direct sound to give the mirage of a "sonic projection with direction".

Few use them any more.

Regarding Anechoic Chambers.

I have built and used many anechoic chambers, and was thinking at one time about building a small 7' x 7' x 6' chamber to sell to audiophiles who might find them fun to assemble and use in apartments or other applications where they wanted to listen at concert levels, without disturbing neighbors or whatever.

They could be placed in large closets, garages, basements, attics or where have you and the sound would be unbeleivable. Even modest equipment yeilded some very impressive, realistic, listening.

The sonic virtues of this type of listening has not been experienced by many, and I can only say the you can place yourself into a live recording far deeper than any other listening environment.

I have been there many times. I currently use a "modified" LEDE type room which also works well for most purposes.

Don't make the mistake of visiting JBL or some speaker company's chamber, (designed to measure speaker sound only) and think you know what anechoic listening really is.

But in any event, I just wanted to "sound off" on the dispersion issue. The point being that any dispersion any wider than your ear is not used in the ear/brain recreation, unless it has hit a surface and becomes a reflection, and then as someone else has stated it is a "distortion". A distortion is any thing other than the original signal that has be added to or subtracted from the original.

In the standard listening room we probably have a "very high" % of reflected sound/distortion. I mean it could be 40% or so. Imagine buying an amp that had 40% distortion!!

And as a final thought, many seem to read the scientific literature written by well respected Acoustic Engineers and researchers and "mis" interpret the info, and worse yet many well credentialed Acousticians,and experts do the same thing.

While physics and acoustics are "in stone" as to their properties and principles, their applications to venues and reproduction environment are "VERY" different.

The largest and main difference is that in a "performance venue" the space is designed or treated to "USE" the environment. Devices like diffusors and such "are" valuable to acheiving a good even covering of the original space.

In the "reproduction environment" that is not the case.

Anyone who confuses the two will never hear what is on the recording from the original venue.

Again, this is not a problem if you like the "sound shaping" you are doing. I certainly used to.....Until I heard about 90% of the real thing, and I haven't been the same since (OK no jokes)

I hope that all makes sense, and I also trust that those who are ecstatically happy with their sound do not take offense. It is just physics and acoustics, and beleive it or not, you're as much an expert as the next guy, cause you know what you like.

And that is what counts.

Billhound,
1200 s.f. is absolutely huge. about as big as my whole house. I'm listening to my Shahinian Diapasons in a 12x15 room with 9 ft ceilings and they sound great- wicked bass node however. I know Richard Shahinian has his Diapasons set up in a very large room with high ceilings- kind of a factory type setting from what i have been told. By all accounts his setup sounds spectacular.
They must sound pretty darn good outside as well. A fellow by the name of Carl Salerno who used to sell Shahinians near Kenosha Wisconsin had a pair playing outside of his home on Lake Michigan. The neighbors stopped by thinking he had live musicians in his back yard.
The Diapasons have massive power handling. something like 800 watts I believe. These things really can approach the energy created by a live band.
As far as the reflective walls and floors go, I would suspect this room could have problems. Rooms that are too highly reflective can be a pain. In my experience, if peoples voices become muddled due to all the reflections, then your speakers are going to have problems also.

Hi Billhound,

In general, a large room is desirable because it introduces a greater time delay between the first-arrival sound and the onset of significant reverberant energy. This is probably more true for directional speakers than for omnidirectional ones, but both types would probably benefit from a large room in this respect.

The larger the room, the more the power response (summed omnidirectional response) tends to dominate the perceived tonal balance. This is because as you move farther away from the speakers, the loudness of the direct sound falls off more rapidly than does the loudness of the reverberant energy. With conventional speakers, the tonal balance is likely to be audibly degraded once you move back far enough for the power response to dominate. With omnis or other consistent-pattern speakers, the tonal balance will hold up better in a large room.

To given an extreme example, once upon a time I hauled my then-pair of big home-brew speakers (1" tweet, 7" mid, two 15" woofers) to an informal dance held in a church's activity room. To my shame and horror, my beloved behemoths sounded sluggish on bottom, harsh in the mids, dull on top, and overall quite fatiguing. I was mortified, as I'd been letting the locals know what a kick-butt speaker builder I was. Now I understand that those were the wrong speakers for that application, as the power response totally dominated the perceived tonal balance in that large space and their power response was quite poor, having never been given a second thought by their designer (ahem). That's why people use horns or horn/woofer hybrids at dances - they have a much better power response, even if up close and in the "sweet spot" conventional speakers would sound better. High output omnis like the Wolcott Omnisphere also work well in this sort of application.

Getting back to your 1600 square foot room with 16 foot ceilings, I would definitely argue in favor of a speaker that generates a tonally correct reverberant field over one that does not. You may or may not prefer a very wide-pattern speaker like the Shahinians; if you do, they'll sound great in there. In a medium-wide but still consistent pattern speaker, you have full-range planars like the Sound Labs and big Maggies, and dynamic dipoles from Gradient and Audio Artistry. If you like a narrower pattern speaker, then for a large room you might consider horn-based systems like the offerings from Edgarhorn, Classic Audio Reproductions, eXemplar, Pi Speakers, Zingali, SP Technologies, and the Klipsch Heritage line. [disclaimer - I sell two of the brands mentioned here]. But dealing with a 1600 square foot room with 16 foot ceilings is a nice problem to have.

Well, them's my thoughs.

Duke

To me a true binaural recording uses a dummy-head mic, although again, in the end the playback system positioning remains a rather arbitrary and subjective thing by comparison.

Binaural Recording Baby! - If you want to feel like you are there! So how come nobody does it? Jazz At The Pawnshop, clearly one of the most successful recordings of all time, was done with a binaural setup. From the Proprius website:

"Palmcrantz rigged the main microphone pair facing the stage, about two metres above the floor. These microphones were Neumann U47 cardioids, spaced 15-20 cm and inclined at an angle of 110-135 degrees.

This ORTF stereo technique - named after the French radio which introduced this simplified dummy head technique at the beginning of the sixties - was, according to Palmcrantz, the best method for optimal stereo effect and spatiality.

- Real stereo effect can only be achieved by placing the microphones in a similar way to the disposition of the ears.

Such a pair stood in front of the stage at Stampen and another pair was placed to the right of the stage, facing the audience in order to recreate the right "live" feeling. Some auxiliary supporting microphones were also necessary. One microphone was placed next to the grand piano standing on the right-hand side of the platform with its lid open, and Palmcrantz hung two cardioid Neumann KM56s over the drums on the left side of the stage. The bass, standing in the middle, and connected to a little combo amplifier on a chair, was supported by a Neumann M49, also in omnidirectional mode. The microphone was placed in such a way that it caught sound both from the instrument and from the amplifier's loudspeaker. "

I had a feeling this thread would get around to this end of things eventually. One of the biggest problems for us trying to reproduce music at home is inconsistent recording technique/methodology.

If all recordings were done this way I don't think you'd want/need Omni speakers to give you that feeling of presence.

Very interesting thread with a nice range of opinions.

I'm wondering if anyone can comment on how an omni-like speaker such as a Shahinian or an Ohm might be expected to fare in a very large space- say 1200 square feet with 16' ceilings- with reflective walls and floors. Is this kind of space more or less likely to take positive advantage of the design principals behind an omni.

As others have stipulated, the listening room's added reflections are distortions. But we need to always keep in mind that "what the mics heard" was insufficient to represent what a human listener at the event would have perceived, and that what they did hear was judged largely based on the engineer's experience of monitoring and mastering in control rooms that are neither performance spaces nor anechoic chambers, and about what type of finished product will sound best played back in a typical home listening room through typical home speakers. A recording is not an objective 'verite' account of what happened, but a subjectively molded account derived from certain common assumptions intrinsically embedded in the production and reproduction processes - one of which is that there will be some liveliness to the listening room.

This also goes to my point about a speaker's radiation pattern and the acceptance pattern of the mics not necessarily being commensurate, but quite possibly incompatible, if we want to minmize listening room reflections by limiting dispersion (and often even if we don't). The simplistic assertion, made by some speaker manufacturers, that speaker radiation must somehow mimic microphone acceptance is further undermined by the implicit, but false, assumption that all recordings will be minimally mic'ed and that we can even know the acceptance patterns of the mics used, much less their positioning. For recordings assembled from multi-mono multi-mic'ing, and of course for electrical direct-injection into a recording console, the relationship simply doesn't exist at all. A more pertinent relationship might be that of the radiation pattern of the mixing and mastering monitors to that of the home speakers, but of course that can't be a consistent thing. In the final analysis, the best way to assess speaker radiation pattern must be subjective auditioning in the room in which they will be placed, using the kind of music which will be played through them, by the person who will be doing the listening.

About Karl's point #2, although it's true to a certain extent that if the listening room could match the recording venue, then the overlayed refections would be more "consistent", they would still be just as distorting. And the problem would be worse the larger and livelier the two rooms were. However, for smaller and relatively 'dead' rooms, I think we have some evidence in favor of this hypothesis, however unimportantly. Many of us will own some of Rudy van Gelder's vintage Blue Note jazz recordings (mono or stereo), hundreds of the earlier ones of which were taped right in his New Jersey home's furnished living room, employing minimal mic'ing. Despite the facts that these recordings are bandwidth-limited, afflicted with dynamic distortions, and subject off-axis and less-proximate instruments to premature roll-off, nevertheless many can display a scary amount of the familiar quality of sounding especially 'real' when listened to from another part of the house outside the listening room, where their flaws are not only less obvious, but where the direct and reflected room sounds have melded into one indirect sound deviod of specific spatial cues, regardless of the speakers used. In this narrow sense, these records can rather easily exceed higher-fidelity concert hall or studio recordings. My theory has long been that this is precisely because they were recorded in an acoustic environment presumably very similar to most people's playback environments. Try it sometime...

Interesting thread, sorry I just joined in. Only a few comments, which I'll keep brief.

1. I agree in theory that the fewer room reflections the better, IF one only wants to hear what the microphones heard. However, many people want to hear more than that, and that is their prerogative. Subjectively, if added room reverb makes it sound more 'live' to you, then that's what you should be after. It's still a free country, after all.

2. The closer the listening room is to the size of the recording venue, the more 'real' the reverb is going to sound, because the reverb delay times match. Trying to recreate a full-blown concert hall sound in a den is not going to work, no matter what speakers you're using. Unless you happen to have a den the size of a concert hall, in which case you can use whatever speakers you damn well please.

3. Most people haven't ever studied room acoustics, and think that adding absorption to a room willy-nilly will make it sound 'better'. Not the case, unless you just happen to be very lucky, and often it will make it sound worse. What is really important is to (1) diffuse the reflected waves, and (2) make the in-room decay time the same at all frequencies. A much harder task, and one which requires some actual measurements and math before pasting acoustic foam all over the walls.

4. In typical small rooms, one of the biggest improvements you can make is to kill the first reflections from the side walls, back wall, floor, and ceiling. It isn't nearly as good as a dedicated room, but it's a lot better than nothing at all. Anyone who has done it will agree-- it makes the soundstage open up dramatically and vastly improves the clarity as well. Strong, early reflections are a very bad thing, far more so than diffuse, later ones.

5. As a longtime fan of the Ohms, I would say that IMO, what makes them so special is not necessarily their radiation pattern, but that they approximate the theoretical ideal of a full-range monopole transducer. Their natural spatial coherence and time/phase alignment is likely the main reason they sound so "right", far more so than their radiation pattern.

Best,
Karl

re: the GMA Continuums - I think it's probably the associated equipment, or the room itself - or maybe just my ears - but I figure I'll go back with some tube stuff and vinyl and try again (if they don't sell first). But I'll tell you, it's been really hard to match the smoothness and neutrality of the DQ's - very underrated speakers because they're not the newest whizzbang technology. They have a bit of a dip in the low-mids (probably where the crossover point is) but I may just upgrade the caps and tweeters and live happily for another year or two, until I move into a big enough apartment to fit Avantgarde Duo's.

Opalchip, my guess is that Roy would say "Negatory" on the towel stuffage idea! ;-) I think a lot of DIY tweakers would be interested to hear from Roy regarding his choice of port placement. Having spoken to Roy several times, there is no doubt he would provide us with a logical and eloquent basis for his decision.

Your reaction to the proceived brightness in the high frequency range runs counter to the impressions I've heard from C-3 owners, but as you pointed out - maybe they weren't fully broken in.

If anyone is interested in seeing two industry professionals comment on in-room reflections, yesterday a couple of very interesting posts were made over at audioroundtable.com (I just stumbled across them). Follow this link to a post by Wayne Parham of Pi Speakers, and be sure to read the reply posted by Dr. Earl Geddes:

http://audioroundtable.com/HighEfficiencySpeakers/messages/1684.html

These guys' comments tend to support my "the reverberant field matters" and "reflections can be our friends" approach, so foes be warned! ;)

Cheers to all - those into bouncing off the walls as well as those into padded cells!

Duke

GMA Continuum 3's - Just listened to a pair that's for sale near Modesto, CA which I probably should buy - but I'll have to go back again. My initial impressions, without being able to hear vinyl which is pretty much all I listen to (I brought a TT but we hadn't realized that the owner had no phono section) -

Overall, really great speakers. Some of the best I've heard.
Dynamic and immediate is an understatement.

My main concern is they seemed a bit bright in the upper-mids for my tastes, as many of the modern designs seem to be. For example, the female chorus in Steely Dan's Babylon Sisters didn't have that sweet, smooth, harmonic sound that they should - they were somewhat etched and stinging especially as volume went up. (Don't worry - I don't listen to a lot of Steely Dan, but there's a couple of tracks I use for evelauation purposes...)

The Mid-mids and Low-mids and Bass were SPECTACULAR, as was imaging and coherence. I'm not generally a fan of ported bass designs and this one is not only ported - but ported UP directly into the open-baffle rear wave of the midrange driver. An odd decision designwise. Do you think Roy would let me just shove a dark gray towel in there?

When I get a chance to go back, which is about a 2 hour drive, I'll bring a tube pre-amp (Granite Audio) with a phono section and see if the vinyl/tube combo tames the upper-mids.

All in all, though, when I got home I was very happy to be back with my trusty DQ-20i's. They lack serious "punch" but they are so neutral and so listenable, they've proven hard to give up. (Just spent 4 days intensively A/B'ing against Alon V Mk. 2's and I like the DQ's better - mostly because the Alons pass too much rear wave out to bounce off the back wall.) Also - believe it or not - the DQ tweeter is better.

BTW - If I don't buy evetually those GMA's somebody else out there ought to - at $4000 they're a steal compared to the new price, and these really are like new (+ already broken in!).

I just had what is probably an absurd idea. There is a parallel thread which has created as much diverse opinion as this thread. In it folks are discussing the pros and cons of multi channel. Why not combine the two threads so we can discuss in a multi channel set up, should we use planers, electrostats, bipolars, direct radiators, whatever. I'm sitting here visualizing a room with Shahanian speakers set up in all five (or 6) positions. Mind boggling. :-)

Zaikesman: I probably have the terms switched. The Scintilla ribbon wraps over. The back trace ribbon is pushing outward at the same time as the forward facing ribbon. The part that confuses me is while they are both pushing, the rear is pushing backwards.

A panel pushes forward while pulling the opposite direction.

Which type is in phase, and which is out of phase?

This would be a good thread for Roy Johnson to chime in on. Roy, you out there? It sounds like Opalchip is of the phase coherent and time alignment (1st order XO) camp.

Opalchip, have you heard Green Mountain Audio speakers? It sounds like they'd be right up your alley. Besides the Sequerra's what other speakers currently on the market do like?

Muralman1: The radiation pattern and phase relationship you describe is dipole, not bipole.

A little off topic, but on theme, is the build, and sonic differences between The bipole Apogee Scintilla, and other dipole Apogees. In Apogee circles, it is a recognized fact the Scintilla's performance is touched with magic. I attribute the difference to the wrap over tweeter ribbons of the Scintilla. This creates two fan shaped radiation wave patterns front and rear, out of phase with each other.

Never done any serious outdoor listening, but I have heard speakers (Maggies) syspended from the ceiling near the center of a barn that was so big that I'm sure there were no reflections to speak of. The best IMHO. But not everyone has a barn.

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.

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

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,

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?

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.

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.

Audiokinesis- Duke, As always your explanations are insightful and appreceiated. I'm glad you brought up the headphone point. I really think it validates your argument.
Since adding RPG Skyline diffusors at the first reflection point from my speakers, the sound has improved drastically. My experience then is that the sound improves when it is "sprayed" about.

Summitav, you make a very strong and I must say hard-to-dispute statement:

"First and foremost, "ANY" sonic artifact created "after" the recording process, in the reproduction space, cannot be reality, and can do nothing but degrade the original."

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?

Let me start out by noting that recordings are made to be listened to in a reverberant environment. If they were made to be listened to in anechoic chambers, they'd be mixed accordingly. (Some recordings are made specifically for playback through headphones, and I'm told that they sound wonderful through a good set).

So assuming those of us who have invested in loudspeakers are not insane (okay I know that's taking a leap...), 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.

The loudspeaker/room interface plays a major role in three critical areas: Spaciousness, image localization, and timbre. Let's take a look at each:

"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.

On the other hand, early-arriving reflections are the enemy of precise image localization. And strong, distinct, laterally-arriving early reflections are unfortunately the worst offenders, tending to blur the image and even altering the tonal balance of the sound. So already we see a conflict here between the good things that reverberant energy can do, and the bad things it can do.

Timbre relates to the harmonic structure of a sound; the same note sounds different on different instruments because of their differing timbre. Room reflections will inevitably influence the perceived timbre, as the reverberant energy's spectral balance is summed with that of the first-arrival sound by the ear-brain system. 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.

Now, using directional speakers in a fairly live (yet diffusive) room can work quite well. The directionality of the speakers reduces the number of early reflections, and that same directionality builds up the reverberant field more slowly than wide-pattern speakers would. But the key thing is, the radiation pattern should be as uniform as possible over as much of the spectrum as possible, and this is rarely achiecved with conventional loudspeakers. Most of what passes for "directional" is really "narrow pattern at some frequencies, wide at others, and omnidirectional in the bottom three or four octaves". In an extreme case, such a speaker may well sound best when listened to in the nearfield or in a semi-anechoic environment.

In my opinion the main advantage of wide-pattern loudspeakers isn't necessarily in the relatively higher ratio of reverberant to direct energy; rather it's in the much closer correlation between the tonal balance of the direct and reverberant fields. This promotes natural-sounding timbre. Although there is a trade-off relationship between spaciousness and sound image localization, by diffusing or (if necessary) absorbing the early reflections it's possible to get good results in both areas.

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. Most of us have studied and auditioned extensively to find the finest pair of speakers we could reasonably (ahem) afford, while relatively few of us have pursued headphones with anything remotely approaching the same passion and budget allocation (or budget-busting, as the case may be).

If being a serious audiophile requires that I dispose of my omnis then I don't want to be one. Summitav and I live on different planets. My planet and my speakers are more or less round. 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? I understand that some prefer the anechoic monitor experience. But I'll bet a dollar thata majority of listeners would prefer the sound of a good pair of omnis over a monitor setup.
Amar Bose really was on to something. Most "audiophiles" laugh about him and discount his work. I think they are making a big mistake.
As Summitav says, it is a preference thing. I just hope that more people make it a point to hear both types before they spend big bucks on a system.

Hi All,

This response is not to questions anyones opinion or sonic preference, "but" it seems that there is significant misunderstanding (even by major manufacturers) regarding reproduction of what is on a recording.

First and foremost, "ANY" sonic artifact created "after" the recording process, in the reproduction space, cannot be reality, and can do nothing but degrade the original.

While bouncing sound around the room can be quite pleasing, it is not true to the original recorded event.

Additionally, the concept of "wide dispersion" as a good thing, is ill conceived. The psychoacoustic recreation of a performance through 2 stereo speakers will only be accurate if all room interaction is reduced as much as possible.

Further, the miked ambience and reflections from the original venue are extremely delicate and subtle. They are easily destroyed by adding a second group of "in-room" sonics that cannot be filtered out.

The soundstage, and images on, and in it, are recreated by the "combination" of clear and detailed information from each speaker by the ear/brain.

A serious audiophile is generally after the most accurate reproduction of that signal. Degrading it by "spraying" sonic info all over the room cannot accomplish this.

Now, in all my years, I have certainly heard "many" beautiful sonic delights that "were not" true to the original, and further more, might even have been "better sounding" than the original, by using the room.

Amar Bose worked for years studying this application to a science. Only problem is, it doesn't work to reproduce the original performance.

Again, this is not meant to "ruffle feathers" of those with Bose, or B&O, or MBL, or even Maggies, but taking the room "out of the sonic equation" will take you closer to the original performance.

Really, its a preference thing.

Hassel: i've heard both brands of speakers, but never with anything remotely resembling similar electronics or in the same room. As such, i'm no help there. Sean
>

Living in Moscow, I have the luxury of being able to go to a lot of concerts for litte money, especially classical music. My favourite venue is the Great Hall of the Moscow Conservatoty, which is as beautiful as it offers outstanding acoustics. I go to jazz clubs, and rock concerts, too. Besides of that, Moscow has become a heaven for high end-nuts, as you can go and listen to any high end-speaker imaginable, which I have done often. Having said that, I found that omnidirectional speakers (in my case Diapasons as well) - if well executed, and coupled with good room acoostics, such as dampaning the wall behind the speakers - give me by far the most convincing memory of what the music in the real venue sounds like. I have had quite a few die-hard direct-sound only guys coming over to my place, leaving as converts for omnis.
May I ask one again, then: Did ayone here compare Shahinia and Ohm speakers?

Talk about a coincidence. The speakers in my bedroom system i.e. the time aligned mini-monitors, are very similar to the little Sequerra Pyramids. As mentioned, these are supplemented by two down-firing subs. That system is actively crossed and multi-amped. Sean
>

Hi - (I'm not sure where the DBX post has ended up. I think it will probably appear in Misc. Audio.)

Until 6 months ago I had 8 pairs of speakers here - but I'm in a one bedroom apartment, and my new wife just moved in! I just gave my Ohm/Walsh 2's to a friend because they were too "big". Now it's tame little Sequerra Pyramids in the 2nd system.

On the other hand, she promises to buy me a pair of Avantgarde Duo's when we eventually move and have the space for them!

Opalchip: your comment of "the sound that I enjoy, which is very precise imaging with very minimal coloration" pretty much sums things up. That is, omni's / bipolar's / dipolar's, etc... are all going to produce an image that is more vague than a focused field type of speaker radiation pattern. As far as colouration goes, individual speaker placements, individual room acoustics and individual sonic preferences are going to dictate what is or isn't acceptable to us as individuals.

Personally, i've got multiple different types of speakers in various systems and enjoy them all. Time aligned mini-monitors with dual down-firing subs in the bedroom, large 5 driver 4 way towers as the mains and surrounds in my HT system, a line array of electrostatic tweeters / stacked electrostatic mid panels / multiple dipolar push-pull dynamic woofers in my main system, very large horns in my basement system and omni's in my office system. They all have their good and bad points, but that's what makes them all "special". As i've posted in another thread and if i had to choose between them all, the one set that i would keep would be my Ohm F's. As such, we are obviously on opposite sides of the coin in terms of what we find to be "important" to us in terms of the type of presentation that we enjoy. That doesn't mean that we can't be friends or share a love of music though : ) Sean
>

Hi all again - I'll be heading out for the weekend so this is my last post for now:

re: Sean - I started a new thread on DBX expanders so as not to drag this one OT with that stuff.

re: Audiokinesis - What you say about mic location is very true, and it has a huge impact on the success of a recording as far as I'm concerned - but that's a whole other topic, too.

The anechoic chamber or overdamped room probably sounds dull because of some or all of these reasons:
-It's not what we're used to.
-You can actually hear how IMPERFECT even a great recording played back on high quality equipment really is compared to the original!
-Room generated Reverb is fun.
-We expect it to be dull - the placebo effect.
-In a properly set-up room we are actually relying on/using wall interactions to cancel out the fact that your right ear is hearing the left channel output, and your left ear is hearing the Right channel, etc. - which dramatically reduces the stereo effect. (It might be interesting to hear a perfectly set up Carver Sonic Holography unit in anechoic chamber. Don't worry, I wouldn't use one at home.)

So, yes, I do hold that all interactions are colorations of what was recorded. But indeed we all may want those colorations because they sound better than not having them by bringing back some of that "liveliness" which was lost in the reproduction process.

re: Holzhauer - I don't have anything at all against omni-directional speakers if that is what somebody likes. My only "objection" when I started posting here was really the quasi-science which is so profusely expounded by the speaker builders/marketers and then absorbed as fact by audiophiles.

I have owned 3 pairs of Ohm/Walsh (with and without the dampening material inside the can) and have had friends with planars (quad/maggie/X-static/ML), which I enjoy but wouldn't want for myself.

As came up in Audiokinesis post - I suppose we do need and enjoy some amount of room interaction, but anyway I look at it - the more interaction the more "distortion" from the original. My experience (for my particular taste) is that the amount thrown off by an omni- is too much, in too many ways, to control properly so that I get the sound that I enjoy, which is very precise imaging with very minimal coloration. I'm going nuts right now just trying to tame the rear wave from a pair of Alon V's to direct and reduce the rear wall bounce.

I haven't heard Shahinians and am always open.

Opalchip,
Not once in your discourse, albeit cohesive, have I perceived any experience on your behalf of omni or pseudo omni loudspeakers. Might you find it in your realm of acceptance, the off chance that the culmination of your scientific understanding could be eclipsed by real experience?
Many with respected opinions (not me) have chimed in on your post. I suspect because they find you intelligent enough to consider their opinions. Listen to some real live music, then listen to some MBL's, German Physiks, Ohms, Shahinians, Quads etc. If you don't like them, fine we'll agree to disagree. Until then, please remain agnostic.

Opalchip, I gotta tip my hat to you for consistently holding to your convictions, even if they're very different from mine. I have a feeling your ideas are more the norm than what you're finding on this thread - I think you've stumbled into a hotbed of believers in planars and/or poly-directional loudspeakers (to borrow Dick Shahinian's term).

A comment about one of your arguments, if I may: While it is true that the microphone picks up hall ambience cues, microphones are usually placed much closer to the performers than listeners would normally be. So, relatively speaking, they pick up a much higher proportion of direct to reverberant sound than what a listener would hear in the same venue. This isn't always the case, but usually is.

Also, the direction from which reflections arrive make a difference in how they are percieved, and in most venues the reflections arrive from all around rather than from the exact same direction as the first-arrival sound. Reflections that arrive from the sides, and well delayed in time, are particularly beneficial in conveying a sense of ambience and acoustic space.

My father has done research in anechoic chambers, and he reports that music live or reproduced in an anechoic chamber has incredible clarity but also sounds dead and boring. I have not listened in an anechoic chamber, but having severely overdamped my listening room as an experiment let's just say I'm sure it wouldn't be my cup of tea.

My conclusion from fairly extensive research in the Journal of the Audio Engineering Society and other publications, and from my own crude experiments, is that the ideal would have the direct sound to arrive completely free from early reflections, then for the reflected energy to begin to arrive perhaps 10 or more milliseconds later, and then that reverberant energy would build up and decay over about 50 or so milliseconds.

However, if I understand your position correctly, you hold that all reflections are colorations - even those inevitably part of a live performance. So there is little point in me arguing that there's a right way and a wrong way for a loudspeaker to interact with the room if you see all room interactions as inherently detrimental. I doubt you and I will find much common ground here other than our passion for audio well reproduced, whatever that may mean. Hey, that's enough for me. I'd love to hear your system some day, and if you're ever in New Orleans give me a holler and come hear mine.

Cheers,

Duke

Opalchip: A microphone picks up whatever is fed into it, both direct and reflected energy. It can't discern if the primary or reflected signal should should dominate as it can't differentiate between arrival times and their individual intensities. In effect, it becomes a recorder of acoustic activity at that specific point in time and space based on the specific pick-up patterns of the mic being used.

The Walsh driver simply re-radiates the energy that was captured at the mic as a point source and re-radiates it into the listening environment as a point source. The fact that the original ambient sounds heard during the recording could be heard at every point in the room, and are pretty much preserved and reproduced due to the pseudo-omni radiation characteristics of the Walsh design, is one of the most endearing properties of these speakers. The fact that there is only one driver acting as a point source for each channel reduces time / phase distortions to a minimum, hence the preservation of natural harmonic structure. This too is a very endearing quality of this speaker design. The effects of binaural recordings as heard on these speakers is pretty amazing.

Other than that, each musical note has a primary frequency and multiple harmonic frequencies. These harmonics vary in spectrum and intensity. Any device that tries to separate the audio spectrum into different segments will introduce distortions into each note reproduced. That's because the time, phase & amplitude of the primary note vs that of the harmonics will not remain cohesive in presentation.

As a case in point, the specific device that you mention is capable of expanding multiple different frequency regions at different rates. When doing this, it means that a harmonically rich instrument ( like a Cello ) that is centered in one specific frequency section may be expanded at a different rate than the harmonics, which might fall into one or two different frequency spectrums. As such, each spectrum is / can be expanded at different rates, which in turn varies the amplitude of the harmonics in respect to the amplitude of the primary notes.

The reverse of that is also true. That is, an instrument that covers a very wide range of the audio spectrum ( like a piano ) can have different levels of expansion applied to it across the entire band due to the spectrum segmentation that the device does as part normal processing. This would take place on both the primary note and the harmonics.

As such, expanding a compressed recording could only be done optimally if the algorythms used during recording and playback were exactly the same. Given that this is next to impossible given the differences in recording, mixing and processing techniques, the end results of attempting to expand a compressed recording can be very "interesting" to say the least. I will agree that "expanded" music sounds noticeably more dynamic and "punchy", but at the same time, it also has a certain "artificiallity" to it. On top of that, quite a bit of electronically generated music IS compressed, even when played live. Electric guitars, bass guitars, electronic keyboards, etc... are often processed in a certain manner with the musician specifically desiring certain sonic attributes that compression / clipping bring along with them. Trying to "undo" what was meant to be, both live and on the recording is nothing more than a distortion. These distortions may be pleasant on certain recordings, but it all boils down to a matter of personal preference vs articulate preservation of what is on the recording. Sean
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Opalchip...The sound generated by a point source speaker becomes, within a few feet, a planar wavefront, just as you have described. By generating a planar wavefront to begin with the planar speaker is (neglecting for the moment any reflections) simulating a point source at a greater distance. As a result of this the SPL falls off much less rapidly as distance to the listener's position increases, producing (IMHO) a very stable and uniform soundstage throughout most of the listening room. This characteristic of planar speakers, more than their inherent bidirectional nature, accounts for the sound that some people like.

Dear Newbee - I wasn't really serious about the DSP. But I listen only to vinyl and the DBX (even a 3bx) is IMHO essential. I really have pretty good ears and have tried to find a fault with this thing and can't. It's the only add-on I have. The sound is soooo much improved. I haven't had anyone listen who wasn't floored by it. It's takes compressed analog (like almost every record ever made), and restores the dynamic range and punch that it had - there's no going back once you hear it. There's nothing magic about compression that can't be reversed with a proper algortihm.
I know many vinyl/audio snobs would have a kneejerk negative reaction to such a device, but then they've just bought a $5,000 tonearm to listen to highly compressed source material with numerous clicks and pops? It ain't that accurate to begin with.

Damned if you don't and damned if you do I guess....

Any Audiogoners in the SF Bay area who'd like to stop by hear it are welcome. You'll be on Ebay buying one within hours.

OK - I really have to get out of here this time...

I'm not disagreeing that many might find the Shahinian sound pleasant. But it is just that, a "sound". I, personally would rather hear (usually) the piece as it was recorded.

Don't take this as directed personally but: One thing people don't seem to get - the acoustics of the hall are ALREADY IN THE RECORDING - as recorded (if it's done right)! You may enjoy adding your own reverberation, but if you play back a CD recorded in St. Paul's Cathedral on a great system in an anechoic chamber, it's going to sound more like it was recorded IN ST. PAUL'S CATHEDRAL, than if you play it back in a large tiled bathroom.

The reason people like to sing in the shower is because the reverb from the tiles makes them sound "better". That doesn't mean they're ready for the Met. So if you like adding reflections from your walls that's perfectly fine - I have no prejudice about what people like - but it's not a more accurate reproduction of what was recorded.

Eldartford - The fact that an instrument is larger than a cone driver doesn't mean the driver can't reproduce the sound that we, as humans with ears, would hear if we were sitting a reasonable distance in front of it. The "planar speaker" argument which keeps popping up here completely misinterprets the mechanics of both recording, wave theory, and human perception.

1. Our ears, like the microphone, also only sample a small portion of the "wavefront". All we need, and in fact, WANT, to do is accurately reproduce that little portion of the wave. The whole point is that the microphone's diaphragm takes the place of our ear. It's "sample" is about the same size as an eardrum. Therefore, any driver larger than the mic's diaphragm is capable (theoretically) of fully reproducing the same sounds the mic heard. The only issues governed by driver size are volume and distortion - (the larger the driver the louder it can play a certain frequency range, but the more prone it is to distortion at a given level of power input.)

Otherwise headphones wouldn't work. They're much smaller than a cello. The reason planar headphones sound good has nothing to do with the size of the wavefront or the drivers, and the reason some people like planars has nothing to do with the "shape" of the original or reproduced wave.

2. All a speaker can be asked to do is accurately regenerate the information that was recorded (sampled) by the microphone. Making the driver bigger or smaller doesn't add any data that was lost in the size of the "sampling", if there really were. Even assuming that a cello created a strange, planar wavefront*** (see #3. below) that had different properties along it's "face", a planar speaker can't reproduce the waveform that was created by the soundboard - it can only reproduce the sample that was picked up by the mic. It brings to that sample certain sonic attributes of its own - but not more of the cello's attributes than a cone driver of equal quality.

3. There is no "cello-soundboard-shaped wavefront" that zooms by the listener. If there were, by the time it got to the back of a symphony hall, all you would be hearing would be the vibration of a 1000ths of an inch specific section of the soundboard. Someone sitting in the seat 5 over from you would hear a different concerto than you. Waves don't work that way.

If you drop a brick in a pond - are the ripples that emanate outward rectangular? Yes and no - for a very short distance they are, then very quickly they're not.

Why - because the wave and it's medium constantly interact with each other. This rapidly "smooths" the sound to a uniform waveform (at reasonably equal angles from the source). Within a few feet the wave IS the same as if it came from a point source. 20 feet out in the pond you would not be able to tell me whether I dropped a brick or a bowling ball by lookint at an ear-sized sample of the rings emanating from the center.

Have a good weekend all.

Opalchip,
Come listen to my Shahinian Diapasons. Then you might change your mind. I think of sound like light. Direct light in the eyes is irritating. Reflected and diffused light is pleasant. The word distortion does not come to mind when listening to the Shahinians. The word real does.

If reflections are distortion then you must think the ideal listening room is an anechoic chamber. I can assure you that it is not. The most experienced acoustic engineers use both diffusion and absorption in room design.