What is your opinion regarding electrostatics?

Hello Herve, The truth of the matter is, once you live with a good Electrostatic or Planer, the midrange of conventional drivers may be hard to return to. Certainly ESL dynamics are constricted, as well as the bottom octaves lacking in weight and slam (but not on String Bass). All of this fades into inconsequence when voices and the majority of middle frequencies are reproduced thru these panels.
This has been the case as far back as the KLH-9 days as well as through Quad, Stax, Beverage, Sound Labs, Acoustat and Magneplaner to name the ones I am familiar with.
Amazingly, there are many audiophiles that do not like the sound produced by panel type speakers and opt for B&W type of conventional monitors. While these will satisfy the other needs (SPL, slam etc) they still do not approach the panel level of "you are there".
Ribbon drivers, while even faster than ESLs fail to retain the "Warmth" level present in the human voice. You get all this fabulous clarity, speed and air, yet you can never get all the metallic sound out to get you to REAL.
As a furthur thought to Sean's excellent post above, I find the backwave (doublet) dipole to be the ESL/Planer's greatest Strength, and a huge contributor to the live sound illusion. (Maybe Amar was right about that after all!!)
There is a group of Audiophiles that I respect who regard the Western Electric (Altec) 755A driver the equal of a ESL midrange. I know that enough good ears have reported on the sound of these historic drivers to warrent possible truth to the statement...........Frank

Sean, what an incredible post! You did a superb job of laying out the merits of horns and 'stats without becoming "partisan".

I'd like to suggest that the dipole radiation pattern of a full range electrostat is actually an asset rather than a limitation. The only significant placement issue is getting them far enough out from the wall behind them, and five to seven feet is usually adequate. You might want to treat the first reflection points with a bit of absorption or diffusion, then fine tune the toe-in angle, and you're pretty well done.

A good full-range dipole has three significant advantages over a direct radiator loudspeaker:

1. The bass is significantly less colored by the room.
2. The direct and reverberant fields are more alike.
3. The sound field more closely approximates a live event.

A dipole does not excite room modes more than a monopole speaker - in fact, it excites them far less. This is because a dipole's figure-8 radiation pattern puts 5 dB less bass out into the reverberant field than a monopole's spherical radiation pattern. True a dipole will excite the room's front-to-back standing wave modes (and so will a horn), but it will put much less energy into the side-to-side and vertical standing wave modes than a direct radiator does. The result is much better pitch definition, because the room isn't contributing nearly as much overhang to blur the decay of the bass notes.

Because a well designed dipole (such as the Maggie 3.6, 20.1, and full range Sound Labs) maintains pretty much the same radiation pattern all the way up and down the frequency range, the reverberant field will have the same tonal balance as the direct sound. This is conducive to natural timbre and to long-term listening enjoyment, because the brain expects the reverberant field to sound like the direct sound with the room superimposed on top. A direct radiator almost never gets this right because its radiation pattern changes drastically as we go up and down the frequency range. Therefore, its reverberant field cannot possibly have the same tonal balance as its on-axis sound. The result is listening fatigue over time. You can listen to a good dipole literally all day long and never get tired of it (the freedom from boxy colorations probably helps here as well).

A dipole that approximates a line source sets up a very different kind of sound field than a horn or direct radiator can (with the exception of line source direct radiators, like the Pipe Dreams - which have problems of their own). You see, sound pressure falls off with the square of distance from a point source, but linearly with distance from a line source. Okay, once again, in English: As you move farther back from a tall dipole speaker, the volume falls off much more slowly than when you move back from a horn or direct radiator speaker. The result is a vastly different "feel" than what you get from a conventional speaker. This uniform sound field feels more like a live performance, because as you listen to a live performance from forty feet away, the sound field is very uniform in volume and tonal balance.

Alas, Sean, I don't know as much about horns as you do about 'stats, so I cannot give the comparison as even-handed a treatment as you did. I certainly agree that horns do macrodynamics better, are easier to place, and are much easier to drive. So far I have yet to hear a high end hybrid horn system where the direct radiator woofer matched the clarity of the horn. But, in all fairness, I have yet to hear a high end hybrid electrostat where the direct radiator woofer matched the clarity of the panels. Just as the ultimate in electrostats is the full range panel, I would imagine that the ultimate would be a full range horn system. Besides the K-horn, does anybody make one?

Thanks for the kind words folks. While i do appreciate the "roses" ( i'm much more of a gin & tonic or beer man though ), i'm learning just as much from you and your posts. As such, PLEASE continue to share your thoughts and experiences. I would HATE to think that my rambling has made someone feel that it was "unnecessary" for them to contribute to a thread. You just don't know how much that "little" comment that you didn't make might've helped someone else out, so PLEASE don't hesitate.

As to Duke's question about "full range Horn's", i don't know of any others besides the various Klipsch models. These should be considered a "starting point" at best with LOTS of room to move in terms of EASY improvements though. If i ever get my act together ( yeah, right...), i have another set of La Scala's to rebuild. I'll probably do these from the ground up, as they are REALLY beat. This would present me with the perfect platform to try out a lot of my newer "horn based" ideas.

As to Duke's comments about planars and conventional drivers loading bass into a room, my experience is that Planars have only ONE advantage. That advantage can only be used under VERY specific conditions. Otherwise, i find that their dispersion characteristics to be tougher to work with, typically resulting in blurred imaging and OVERTLY lean characteristics when things are less than optimum. These are MY thoughts and opinions though, so that means they are worth LESS than $0.02 : )

I think that we will all agree that LOW freq's are the most problematic area in the audible frequency range to properly reproduce in a reasonable sized room. The fact that LOW frequencies are omnidirectional doesn't help any either. This means that ALL speakers, regardless of their radiation pattern at higher freq's, face an equally tough task in this area. If anything, the fact that many planar speakers don't have a LOT of output below 100 Hz may help them out a bit in this respect.

The ONE way to overcome the "room loading" problem with a planar is to place it EXACTLY at the mid-point of the room. So long as the room is evenly "clustered" with furnishings, etc... the wavelengths and pressure to each side of the panel remain identical. The result is "even loading" with equal reflections. This minimizes the standing waves in the room and will result in the most natural bass response that those speakers are capable of in that room. This does NOT necessarily mean that you will like what you hear though.

While this approach MIGHT work with conventional dynamic woofers running back to back in a push-pull configuration (one wired in phase, the other out of phase), I have never tried it. I would ASSUME that the results would be similar to that of the planar while still retaining the characteristics of the dynamic driver. Whether this is good or bad would depend on your point of view.

If someone has an opposing ( or confirming ) point of view, PLEASE share it with us ( me in particular ). I'd love to compare notes and experiences and hopefully learn something along the way. Sean
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Sean, don't you think that most good planars today have a fairly decent bass response well under 100hz? Just think of the new Quads or the bigger Sound Labs. Also the more expensive Maggies are no slouch in this regard at all. So I find your remark perhaps a bit misleading, at least for a newbee. But just because we seem to be in disaggreement here, I find your thoughts about bass response and planar speaker placement all the more important: When I originally experimented with this, I adhered to the one third/two third rule and got muddy bass amd fuzzy images. Finally I ended up not quite halfway into the room, more or less in the middle between the 1/3 and 1/2 position to get things right.
Also here there are no really hard and fast rules. Every rig and room is different, not to speak of the furnishing in it.
As for Altecs and Klipschhorns, I have of course never heard all and every make of them, but the ones I had the chance to listen to, I found very statorlike, as you said in your first post, but also coloured. So I never really considered horns as an alternative until I came across the a-capellas, which I would suggest everyone look into, who is seriously considering hornspeakers. I don't know however, if they already are being imported to the States.

Hi Sean,

Great to hear from you again! Hey by the time you and I are done, we'll have all these dynamic guys lining up for either horns or 'stats...

You are a true gentleman, and it is a pleasure exchanging ideas with you. Your ideas are worth way more than the customary $.02. I'm a dealer (see the fin on my back??), so my ideas have to be taken with so many grains of salt I oughtta buy stock in Morton...

Okay, here we go...

I gotta differ with your statement that "LOW frequencies are omnidirectional" (which, if true, would refute my assertion that dipole bass is less colored by the room). Low frequencies are only omnidirectional with a monopole direct radiator source. For example, a true low frequency horn would be just as directional over its passband as a midrange or high frequency horn.

A dipole is directional in the bass because, in the plane of the driver, the out-of-phase front and rear waves cancel. In a true anechoic chamber, you would not hear any bass if you stood exactly to the side of a dipole. But you would hear plenty of bass if you stood in front of it. In a room, what you hear to the side of a dipole is the reverberant field.

If you did an overhead graph of a dipole's radiation pattern at low frequencies, it would look like a figure-8 [see - more bass out front & to the back; less bass to the sides]. A monopole has a figure-O [omni-directional] radiation pattern in the bass.

The Stereophile 1998 "Speaker of the Year" was a dynamic dipole called the Audio Artistry Beethoven, designed by Siegfried Linkwitz. Go to this address and you will find an in-depth description of dipole bass: http://www.linkwitzlab.com/rooms.htm

You can also find an excellent but less technical discussion of dipole bass at Gradient's site (the Revolution uses dipole bass loading). Be sure to click on the link to the picture of the bass radiation pattern on the second page: http://www.gradient.fi/En/Products/Revo/Revo1.htm

Hopefully these sites will establish that a dipole is indeed directional in the bass.

Now, I'm sure you'll agree that one of the advantages of a horn is that its directional nature minimizes room-induced colorations. Well, dipoles have the same thing going on with their directional bass - they have significantly less room-induced colorations.

Mind if I try to bolster up my assertion that dipoles have similar direct and reverberant fields?

I said that with a good dipole the direct and reverberant fields sound pretty much the same. Okay, this is easy to test. Go to your Maggie or Sound Lab dealer and turn the volume up louder than normal. Walk into the next room, leaving the door open. Does it sound convincingly like live music is going on back in there? From outside the room, all you can possibly hear is the reverberant field. If it sounds realistic, then the speaker's reverberant field response is very good. By the way, Klipschorns are also very good at this, because their full-range horn loading maintains essentially the same radiation pattern at all frequencies.

As an example of the reverberant field, consider this situation: You're walking past a night club and you hear saxaphone music coming through the open door. You don't even have to look inside - you know instantly if it's live or if it's Memorex. All you can possibly hear through the open doorway is the reverberant field. With live music, the reverberant field sounds right. Over most loudspeakers, it sounds wrong. One of the most significant but most often overlooked factors in the difference between live and reproduced sound is the reverberant field. Papers published in the Journal of the Audio Engineering Society decades ago established the correlation between listener preference and good reverberant field response, but this has been all but forgotten.

I can't think of any arguments in support of my 3rd assertion in my post above, so I'll pass on that one for now.

Just for the record, many planars are indeed capable of substantial output below 100 Hz. Sound Labs and Maggie 20's go down into the mid-20's, and can shake the room, as can the dipole Beethovens mentioned above (which go down to 18 Hz). The dipole active Gradient Revolution system demo'd at the 2001 CES easily went down into the lower 20's, and had by far the most natural sounding bass I heard in any of the smaller rooms (and better than many behemoth direct radiator systems).

Frankly, I don't think placing planars in the middle of the room is necessary (or practical). Perhaps we have had different experiences?

Also, I have heard many planars that have superb imaging and do not sound the least bit "thin". Just like there are horn speakers out there that do not "honk"! I will admit that it takes more effort to get excellent imaging out of a planar, but you also get a greater sense of acoustic space and ambience. A diffuse, well-energized reverberant field is desirable in the concert hall, and in the listening room as well. Again, this from published research.

I gotta ask one clarification. I'm not clear on just what the "ONE advantage" of planars is that you concede. Hey, I gotta trumpet and celebrate any little point in our favor here!!

Hey Sean, I'm having a blast. Thanks so much for writing back. Like you, I invite reply from anyone who wishes to offer correction or a differing point of view, and I will try to offer them the same respect you have.

Kindest regards,

Duke