Electrostatic speakers?

[Newman]

I like to think that engineering without science is like politics without accountability.

Engineering really needs science. Let's walk through an example.

I have to admit I don't put much credence into the more micro type discussions about transducers' properties/behaviors, and seldom give attention to them.

Good, because those discussions are more often than not centred on misattribution. Unfortunately, macro type discussions are not immune either.

As a DIY speaker designer/builder of about every type speaker (except electrostats), I've learned it's easy enough to measure transducers in test jigs and prototypes, to find where pistonic ends and breakups begin, as well as get a grip on polars.

Very cool.

(And not care so much about why.. ..just me...I'm curious enough, but simply more interested in find best sound I can, even it through excessive trial and error.)

Good move. After all, the why discussion is often corrupted with misattribution stirred in a pot of post rationalisation.

I'm all about high-level pragmatic engineering.

I had a career as a specialist in that kind of engineering, making sure the outcomes dominate the outputs. Needless to say, I think it's important.

From that vantage point, here is how I see electrostats offering a unique sound, or at least a sound different from conventional baffled & boxed speakers.
First, the well recognized dipole radiation.

Yep

Second, and at least as important imo, is that being planars they behave as line arrays in both the vertical and horizontal dimensions.

Truncated line arrays. One of the worst configurations in all of audio, as already mentioned.

Vertical line array behavior is generally a given. I view it as a big in-room positive, owing to lines reduction in the lobing from floor and ceiling bounce. Highly desirable.

As long as it isn't truncated by, say, a carpeted floor or a gap to the ceiling.

My positive experiences with DIY floor-to-ceiling and tall CBT line arrays, led me to see that is exactly what electrostats/planars are doing vertically, subject to the same line array principles regarding length of line and center-to-center spacings of line elements.

The implied c2c spacing is part of electrostat's different sound I think. The tighter and continuous c2c spacing (especially for non segmented diaphragm), let's the line behave as line for all frequencies down to where length on line becomes controlling. This is a real boon for VHF, where most all more conventional lines can't achieve necessary c2c tightness.

I think horizontal line array behavior is generally viewed as problematic, with attempts to either curve the diaphragm horizontally or segment it into vertical stripes. I still have the original CLS, which can sound awesome on certain material, but are too colored for most tracks. (I really need to break them out of the closet and EQ them.) I also have a pair of Acoustat-X with the high voltage direct drive amps, that use three identical panel segments for horizontal dispersion. Still use these for comparisons, still love them.

...Phase is the last part of the unique sound a think.
And not just a flat phase trace from not having a crossover(s). It's flat no matter where you measure off the diaphragm.
Flat phase can be done for any speaker, at least on-axis. Heck, I've had flat phase on everything I've built, typically 5-ways including sub as a way.
But good ole separated drivers' geometry changes phase off-axis. ...even on my syn/MEHs which have considerably tighter c2c's than conventional designs.

Anyway, my 2c on why I think stats sound a bit unique. My 2$ comment is my ears hear it

You already know what the correct response is to that last statement.

And let me go ahead and preempt any "sighted listening bias", horse-crap replies.

Trying to divorce the engineering from the science is a bit like trying to divorce politics from accountability. It leads to terrible outcomes.

I've owned and used the Acoustat-X for nearly 50 years. (CLS, although less used, for 30 yr) I'm quite used to their looks and size...no romance there folks.
Heck, they are kinda small compared to a number/most of my DIYs. And double heck, I don't give a rat's ass what a speaker looks like.

I experiment so much, with many different DIY designs, and many different processing techniques...FIR and IIR...DIY's all built strictly off transfer functions and impulse Reponses.
I audibly compare DIYs to DIYs, both within same type to across types (syns vs lines vs coax vs conventional, etc), ... and compare to the stats, a couple of Meyer rigs, various old speakers I have...even a pair of 901 series VI hanging in the garage lol.
Yes, all sighted. I say so what. It's is a rare event when I hear something that stands out as a real improvement. When horses for courses is taken into account, even with a real improvement in a particular design, I know it is only good for the particular course the speaker was designed for.

So science, that's so what.

In the end I care about one thing and one thing only...HOW DOES IT SOUND?

Yep, me too. Under controlled condition listening tests. And that's when they keep on flunking. Which would be near-impossible if your dipole behaviour, line source behaviour, and flat phase behaviour were as significant to preference as your descriptions imply.

Hypotheses about cause and effect are all very well, but they only become real when we put them to the test. And the test needs to be well designed. If the effect being tested is how it sounds, then the test needs to eliminate non-sonic variables.

These realities don't go away just because you call them "horse crap". Accountability bites.

cheers

 

[dlaloum]

@dlaloum we should separate two things here: frequency-selective segmentation of the motor (which in case of ESL almost necessarily means segmentation of the stator, not the diaphragm, you named Quad 63 as an example) and physical segmentation, i.e. segmented suspension, of the diaphragm (Soundfield, Martin Logan).

The motor segmentation might address some directivity issues by preventing the active zone from becoming overly huge for short wavelengths.

As i understand it, it does not have much impact on the diaphragm behavior related to breakup, unwanted bending wave behavior, resonances and alike. Imagine the center of a Quad 2805 or alike: We have a circular are of roughly 10cm in diameter, exciting solely the center of the foil for frequencies of 10K and above. As the foil is flexible, with very little inner damping and no suspension anywhere near, this will cause de facto bending wave behavior, breakup and resonances beyond the active zone, and even within that one, as the motor force per diaphragm area is not strong enough to force the diaphragm to pistonic behavior in case of a resonance or breakup.



You cannot compare these cases, as the vast majority of pistonic dynamic tends to have a comparably strong suspension (surround or spider), stronger motor per diaphragm area, are smaller compared to the emanated wavelengths, and in most cases their diaphragms offer much higher stiffness or inner damping compared to a foil of a planar ESL.

There are similarities with some bending wave transducers, as I understand it, for example NXT and Manger MSW (The latter offering immense inner damping and circular motor structure, so very different diaphragm behavior), as well as tall, non-suspended ribbons if you look at one dimension solely (Magnepan, Apogee). Very large, very light fullrange cones, like Lowther, might also be filed under this category, but the majority of dynamic drivers cannot.

Defining ´Optimal frequency range´ as the one ensuring pistonic behavior and minimum diaphragm area relative to the wavelength, single-diaphragm panels are mostly operating outside their optimal frequency range, if I understand them correctly.

As mentioned, all of this is not applicable to planars with the foil itself being segmented, for example by a grid, like ML and Soundfield are doing it.

This said, I still have sympathy for certain aspects of sound quality that very good ESL can deliver, which are difficult to achieve with conventional dynamic concepts. For treble bands, I see AMTs as the single most promising solution to achieve both at the same time, but this is a completely personal judgement.

And yet.... where the pedal hits the metal so to speak.... ESL's are among the lowest distortion speaker types available...

In the overall competition between magnitudes of distorting input - it seems that the input of panel breakup is far lower than things like cabinet resonance in traditional speakers...

Yes everything is a compromise, none of our options are perfect! But in my experience (Quad ESL57, ESL63, ESL989 ) the electrostatic compromise was/is a particularly good one ( I still have a pair of ESL57 in storage, but my current speakers are Gallo Nucleus Ref 3.2 & B&O Beovox Penta) - as long as particularly high SPL's aren't one of your criteria!

 

[Arindal]

Truncated line arrays. One of the worst configurations in all of audio, as already mentioned.

Claimed by you, but no evidence or theory why is that so.

Not saying here that ESL are ideal in terms of directivity and vertical dispersion, but in my understanding they solve more problems than they introduce in this regard.

Under controlled condition listening tests. And that's when they keep on flunking. Which would be near-impossible if your dipole behaviour, line source behaviour, and flat phase behaviour were as significant to preference as your descriptions imply.

I have done controlled listening tests involving dipoles and ESL, among them tests under blind conditions. While phase behavior was not reliably detected by participants whatsoever, and regarding dipole vs. non-dipole there was distinction but no clear verdict, the directivity resulting from a line source was correlating with the outcomes one would expect, particular in terms of localization stability and coherent ambience.

If the effect being tested is how it sounds, then the test needs to eliminate non-sonic variables.

I agree. But non-sonic variables would be including measurements being known to those who are conducting the test and those taking part (which means essentially a double-blind test). In addition, it would require eliminating all other variables than the single effect being put under test, which includes anechoic frequency response and to a certain degree room influence (visual and sonically), as well as subjective evaluation of sound quality parameters which are not tested.

In my understanding, no-one has ever done such test in a comprehensive manner, at least not meant for publishing the results. An institution I have been with at the time in pro audio research, started to do exactly that, and I myself conducted quite a number of single-aspect blind tests, partly under anechoic conditions, so I have a good understanding how much effort is required and what can potentially go wrong when drawing conclusions.

That is particularly the case with trying to linking measurements showing a very isolated aspect of reproduction, to statistical results of subjective polling which go no further than ´did you like A, B or C most?´. Not to mention the circle of confusion in case recordings unknown to the listeners are used, or, even worse, those which are basically electronic creations being judged on other loudspeakers by unknown mastering engineers.

Trying to divorce the engineering from the science is a bit like trying to divorce politics from accountability.

Agreed, when it comes to understanding and engineering which part and aspect of a loudspeaker work how and do what. But I don´t see any reliable scientific findings telling us anything a priori about sound quality.

where the pedal hits the metal so to speak.... ESL's are among the lowest distortion speaker types available

Cannot confirm this, at least not for certain frequency bands and fullrange ESL. Play some lower bass heavy EDM, and you either get the overload relais clicking, or it is a plasma party.

it seems that the input of panel breakup is far lower than things like cabinet resonance in traditional speakers

I see no connection here, as both aspects happen in completely different frequency bands, and cabinet resonances can be sufficiently suppressed/avoided by good cabinet design, while foil resonances and breakup cannot.

But in my experience (Quad ESL57, ESL63, ESL989 ) the electrostatic compromise was/is a particularly good one

I agree for the particular era of these speakers and a limited number of sound quality aspects, like reverb tonality, imaging stability and midrange transparency. Nowadays, I don´t really see the point in accepting such a compromise. Wondering what ESL supporters think about dynamic speakers offering similar qualities, for example:

T+A Solitaire S
Piega MLS2
PS Audio Aspen FR30
Ecouton TransAR
B&M 25

Or anything like IO Design, Göbel or alike, combining planar tweeters and dynamic line sources/dipoles.

 

[DavidEdwinAston]

Claimed by you, but no evidence or theory why is that so.

Not saying here that ESL are ideal in terms of directivity and vertical dispersion, but in my understanding they solve more problems than they introduce in this regard.



I have done controlled listening tests involving dipoles and ESL, among them tests under blind conditions. While phase behavior was not reliably detected by participants whatsoever, and regarding dipole vs. non-dipole there was distinction but no clear verdict, the directivity resulting from a line source was correlating with the outcomes one would expect, particular in terms of localization stability and coherent ambience.



I agree. But non-sonic variables would be including measurements being known to those who are conducting the test and those taking part (which means essentially a double-blind test). In addition, it would require eliminating all other variables than the single effect being put under test, which includes anechoic frequency response and to a certain degree room influence (visual and sonically), as well as subjective evaluation of sound quality parameters which are not tested.

In my understanding, no-one has ever done such test in a comprehensive manner, at least not meant for publishing the results. An institution I have been with at the time in pro audio research, started to do exactly that, and I myself conducted quite a number of single-aspect blind tests, partly under anechoic conditions, so I have a good understanding how much effort is required and what can potentially go wrong when drawing conclusions.

That is particularly the case with trying to linking measurements showing a very isolated aspect of reproduction, to statistical results of subjective polling which go no further than ´did you like A, B or C most?´. Not to mention the circle of confusion in case recordings unknown to the listeners are used, or, even worse, those which are basically electronic creations being judged on other loudspeakers by unknown mastering engineers.



Agreed, when it comes to understanding and engineering which part and aspect of a loudspeaker work how and do what. But I don´t see any reliable scientific findings telling us anything a priori about sound quality.



Cannot confirm this, at least not for certain frequency bands and fullrange ESL. Play some lower bass heavy EDM, and you either get the overload relais clicking, or it is a plasma party.



I see no connection here, as both aspects happen in completely different frequency bands, and cabinet resonances can be sufficiently suppressed/avoided by good cabinet design, while foil resonances and breakup cannot.



I agree for the particular era of these speakers and a limited number of sound quality aspects, like reverb tonality, imaging stability and midrange transparency. Nowadays, I don´t really see the point in accepting such a compromise. Wondering what ESL supporters think about dynamic speakers offering similar qualities, for example:

T+A Solitaire S
Piega MLS2
PS Audio Aspen FR30
Ecouton TransAR
B&M 25

Or anything like IO Design, Göbel or alike, combining planar tweeters and dynamic line sources/dipoles.

God, those Piega are rather more expensive than 2912X's, for instance!

 

[Arindal]

those Piega are rather more expensive than 2912X's

Certainly true, but if you look at the ratio bucks per Decibel in the lower bass range and apply a logarithmic scale, they might easily cost the same or less.

But I did not mean to discuss value for money, but was asking ESL lovers how they judge speakers with dynamic bass/midrange concepts, that from acoustic theory are similar to planar dipole ESL This might put an end to at least some properties of planars being mystified (like the light diaphragm and transient behavior), while laying the ground for a serious discussion what ESL solely from acoustic point do better than conventional speakers.

 

[DavidEdwinAston]

Certainly true, but if you look at the ratio bucks per Decibel in the lower bass range and apply a logarithmic scale, they might easily cost the same or less.

But I did not mean to discuss value for money, but was asking ESL lovers how they judge speakers with dynamic bass/midrange concepts, that from acoustic theory are similar to planar dipole ESL This might put an end to at least some properties of planars being mystified (like the light diaphragm and transient behavior), while laying the ground for a serious discussion what ESL solely from acoustic point do better than conventional speakers.

Hmm. Very logical Spock!

 

[NTK]

Claimed by you, but no evidence or theory why is that so.

Not saying here that ESL are ideal in terms of directivity and vertical dispersion, but in my understanding they solve more problems than they introduce in this regard.

Because in a typical listening you'll be listening in the acoustic near-field, where frequency response varies with distance?
See figure 10, with a 2 m long source, at 10 kHz, the near-field / far-field transition is in the multiple ten's of meters.
https://adn.harmanpro.com/site_elem...191/AES_May_01_Ureda_Line_Arrays_original.pdf

 

[Fidji]

Certainly true, but if you look at the ratio bucks per Decibel in the lower bass range and apply a logarithmic scale, they might easily cost the same or less.

But I did not mean to discuss value for money, but was asking ESL lovers how they judge speakers with dynamic bass/midrange concepts, that from acoustic theory are similar to planar dipole ESL This might put an end to at least some properties of planars being mystified (like the light diaphragm and transient behavior), while laying the ground for a serious discussion what ESL solely from acoustic point do better than conventional speakers.

Most of those you listed are fine speakers, but not something I would trade my hybrid ML’s for. [just for context - my other speakers are Neumanns, I had Dynaudios, Wilson Audios, have tested whatever, as I have good access. Came back to ESL after detour to Wilsons].

What I do like about my hybrid stats:
- “onewaydness” of the sound, as no crossover in mid/treble region. 250Hz crossover between active woofer section with its own DSP is much easier to manage. That is big part of ESL appeal to me. You get similar from Berylium/Textrene domes in Waveguide, paired with some super expensive mid drivers and low order X-over.
- bass section in current generation of Masterpiece series [opposite active woofers, in my case 2x12in with 2x500W Icepower each speaker] and DSP capabilities is matching to panels seamlessly, especially if you know how to use DRC properly.
- I have never heard any sign of strain or distortion from panels [unlike most of the tweeters that I can make gasp for dear life with some Bach stuff], giving this size and effortles dynamic. They create nice big soundstage, realistiv volume of instrument and voices and I can live with the fact, that imaging is maybe not absolutely pinpoint.
- neutral sound - measured at MLP - I am at +-1.5dB range for linearity. I attend lot of live symphonic and chamber music and where ESL really excel is timbre. Unlike some speaker that have nice spinoramas, but sound like tinboxes.

Saying that, I fully acknowledge,m, that those are not universal speakers - in order to get to what i have written above - they are super fiddly re placement, 1-2 inches can change a lot. They need room acoustics built for them in order to perform properly. I also support them with pro calibration performed via Trinnov, have bass sorted out via Waveforming. Surely, well designed dynamic speakers would perform well too under such conditions.

On top I am able to get deals and trade-ins, that push value for money into completely different territory, as i am, what is considered “very good customer”.

I will be building “reference” [want to hit Lvl 3 of RPA22 cleanly, and get to Lvl4 on some metrics] multichannel music/home theatre system in [hopefully] not so distant future - I will be going for line-arrays for L-C-R, so no stats. I will move ESLs to be one of 2-3 sets of speakers in separate 2CH room [with its separate bass subsystem], add big Genelecs and something highendy - probably some second hand WIlson Audios or maybe will squeeze in some good horns instead. So still want to keep ESLs, but not for L-C-R duties, as I have today [I am forced to combine stereo and MCH into one system, as I have only one room big enough that I can dedicate]

To sum it - i just like how they sound and I have lot of fun listening to them, and this is my only KPI.

 

[ubiq]

I mostly agree with that. Whatever the reason, the panels I have bought after many listening sessions in stores, compared to traditional speakers, whatever the price, sounded less "boxy"; it's indeed a word that get as close as possible to the feeling I felt. I agree it's purely subjective too.
Just for information : the brand I'm talking is not very discussed here, but they produce a nice range of "affordable" panels, and imo the DP115 model could be compared to the ML esl x, specs wise, from what I read.

Home - diptyque audio

Innovative planar loudspeakers, made in France. Diptyque Audio offers an unparalleled acoustic experience with its high-fidelity flat speakers,

www.diptyqueaudio.com

These are panels with bass, for sure, and not hybrid. I have the previous version of the 115, the dp107.
I've decide to add a sub because I listen a lot of electronic music. Xover @ 70Hz. Wonderful.

Cheers

 

[Arindal]

“onewaydness” of the sound, as no crossover in mid/treble region.

I get the idea of what you mean by that, would call it ´homogeneity´. But I have doubts that this is inherent to any crossover, would rather suspect some typical flaws deriving from many crossovers and geometrical designs, but not all, being the root cause (vertical localization contradictions, lobing/cancellation, directivity steps and alike).

You get similar from Berylium/Textrene domes in Waveguide, paired with some super expensive mid drivers and low order X-over.

I agree that such designs in a well-treated room can rival ESLs in terms of midrange and treble transparency, but they are certainly different when it comes to directivity and off-axis behavior.

The examples I have mentioned, all use planar-foil drivers or AMTs resembling line sources, in the treble range, some in the midrange, and they thanks to dipoles or line source properties, are similar in the midrange as well. Hence my question if you have heard any of these.

I attend lot of live symphonic and chamber music and where ESL really excel is timbre. Unlike some speaker that have nice spinoramas, but sound like tinboxes.

No disagreement from my side regarding natural timbre and reverb tonality. I personally would like to have a bit more of pinpoint localization, proximity and broader listening window, so ESL are not for me.

But I am not aware of any speaker having flawless spinorama while sounding like an tinbox. In contrary, I am sometimes shocked by imbalanced directivity evident in the spins of speakers which are still lauded on this board as technically flawless, perfectly linear or whatever. Could you name an example pls?

Because in a typical listening you'll be listening in the acoustic near-field, where frequency response varies with distance?

And? Do listening distances vary manyfold, while listening to music at home? If not, I do not see the problem here, as frequency response can be optimized for the desired listening distance with some tolerance.

 

[MRC01]

Because in a typical listening you'll be listening in the acoustic near-field, where frequency response varies with distance?
See figure 10, with a 2 m long source, at 10 kHz, the near-field / far-field transition is in the multiple ten's of meters.
https://adn.harmanpro.com/site_elem...191/AES_May_01_Ureda_Line_Arrays_original.pdf

Nice reference, very informative.

Note that the angle on page 2 is vertical, or aligned with the line source. The listener is different distances away from points along the line source. Thus, sound waves aligned along the source reach his ears at different times (out of phase). If the listener moves parallel to the line source (vertically), those relative distances change, thus narrow dispersion and beaming. But for any fixed vertical position, if the listener moves perpendicular to the source (horizontally), those relative distances remain constant. Edit: assuming the driver is very narrow, narrower than the wavelength of sound it's producing. Otherwise, the width of the driver is a shorter line source for the horizontal angle.

Another interesting aspect with a big line source is that the listener is typically far field for the bass but near field for the treble. Far field amplitude drops with distance twice as much as near field does. Thus the listener distance from the speakers is a tone control: closer = warmer and further = brighter. Like many things, this could be a "feature" or a "bug" depending on one's goals.

 

[MRC01]

I'll add that the dispersion graphs show a trend that I can over-simplify for intuitive understanding. Call T the length of the transducer and L the wavelength of the sound it is producing.

If T < L, then you get even smooth dispersion (T smaller than L)
If T >> L, then you get narrowly focused/point dispersion (T much bigger than L)
If L < T < 10*L, then you get beamy dispersion with strong peaks/lobes and nulls

Put differently, the cleanest response is in 2 opposite cases - the transducer is either (A) smaller than the wavelength, or (B) more than 10 times bigger than the wavelength (10 is just a rough rule of thumb). (A) has smooth and broad dispersion, (B) is narrowly focused. Technically, one can say (B) is beamy because there are lobes and nulls. But in practical terms, when T gets "a lot" bigger than L, the lobes get so small and tightly spaced, and drop off so quickly, the dispersion becomes clean & tightly focused. In between these extremes, T is bigger than L but not too much bigger, is the "no-mans land" where the dispersion is uneven because the off-center lobes are big enough, and spaced far enough apart, you can hear them. From the diagrams, the worst case seems to be the range around T = 2L to T = 8L.

 

[Arindal]

Far field amplitude drops with distance twice as much as near field does.

That is correct in theory, but in practice such constellation appears for example if you combine an omnidirectional subwoofer with a mid/treble line source. So on top of the farfield/nearfield problem you have a spherical wave propagation vs. cylindrical with a different formula of amplitude depending on distance.

That is a common problem in sound reinforcement, giving every single FOH engineer a headache. In this case, J-lines are used, with a straight line for farfield and curved line for nearfield. Have been attending a concert lately, with pretty extreme conditions, listening distance like 1.5m...85m (!) from the woofers, with single J-lines being flown pretty low (no delay lines, no fillers). Balanced sound at FOH console resulting in bass boost in the region of +25dB in the first rows.

Home conditions, particularly hi-fi, simply don´t need such vast variation in potential listening distance. Even if you have 2 rows, the theoretical ´tone control´ you were mentioning, is usually negiglable, and a compromise in level is possible. And if we are talking about a combination of omnidirectional + line source, you anyways have to have a possible to adjust the balance.

assuming the driver is very narrow, narrower than the wavelength of sound it's producing. Otherwise, the width of the driver is a shorter line source for the horizontal angle.

That is a very important precondition, and a reason why I personally have my reservations regarding larger panel speakers. If the panel is broad (and may it be just like 4" of the active central zone of a segmented Quad), it is basically impossible to have an even treble amplitude over a broader listening window.

 

[Fidji]

But I am not aware of any speaker having flawless spinorama while sounding like an tinbox. In contrary, I am sometimes shocked by imbalanced directivity evident in the spins of speakers which are still lauded on this board as technically flawless, perfectly linear or whatever. Could you name an example pls

JBL, all of them included latest batch of high-end models. They just sound vulgar to me, yep they are loud and have nice dynamics, but it is PA quality of sound.

Also, while I do understand what makes KEFs so well regarded for good objective performance, and there is lot to like about them, I could never get really excited while listening to them. There is something missing in the tweeter performance, probably driven by aluminium/coax combination. Orchestral music sounds recorded, not even trying to create an illusion of the real thing. I had them at my place, when shopping last time for speakers {Blades] and while they are very fine, I just could not convince myself that this is what I can happily live with long term

There is this thing with cheap aluminium coaxes, that I somehow do not like. E.g. for analytical listening I prefer Neumanns over Genelecs. On the other hand I can enjoy well implemented coax e.g. in TADs, so I am quite speaker concept agnostic. I know meanwhile what exactly I am looking for in system sound and right now stats fit the bill for me.

I fully acknowledge the fact, that my personal preferences might be different to majority of Harman control group, although I tend to prefer more neutral “trained listeners” type of sound, for what it’s worth.

 

[Arindal]

JBL, all of them included latest batch of high-end models. They just sound vulgar to me, yep they are loud and have nice dynamics, but it is PA quality of sound.

You mean the horn-loaded, broad, expensive speakers named after mountains? The models I am familiar with, I would file under ´collection of worst flaws apparent in the off-axis measurements´, so I would expect from the measurements exactly the sound you are describing (and can confirm this impression for some models I have heard).

while I do understand what makes KEFs so well regarded for good objective performance, and there is lot to like about them, I could never get really excited while listening to them. There is something missing in the tweeter performance, probably driven by aluminium/coax combination. Orchestral music sounds recorded, not even trying to create an illusion of the real thing.

100% agreed. My theory would be, this particular sound character derives from their tendency to continuously narrow down dispersion angle towards higher frequencies, in many cases with a noticeable step down in off-axis energy somewhere in the 1-3K band. Everything that gives our brain the impression of tonally balanced reverb, blending nicely with the concert hall reverb actually on the recording, is contercarated by this type of coloration. So stereo phantom sources, particularly singers, are ´singing holograms in a vacuum between the speakers´, the reverb seemingly comes from elsewhere (oftentimes the rear) and is very very dull, unrelated to the direct sound.

Is that what you mean to say?

I would conclude it is not the aluminium to blame, but the tendency to have steeply increasing directivity index, which oftentimes is the compromise when trying to design a coaxial without lobing and cancellation effects. Fully agree that other coaxials such as TAD, KSD and MEG, even some of Elacs, don´t have the tendency mentioned above.

 

[MRC01]

... That is a very important precondition, and a reason why I personally have my reservations regarding larger panel speakers. If the panel is broad (and may it be just like 4" of the active central zone of a segmented Quad), it is basically impossible to have an even treble amplitude over a broader listening window.

The ribbon tweeter in Magnepan 3.6 is about 5 mm wide. That should give even horizontal dispersion up to around 70 kHz - theoretically. Of course other factors like interactions with the wider panel of the speaker may affect that. But vertically, being about 1.5 m tall, they should have a narrow vertical range.

My subjective pragmatic experience roughly matches this. I have a couch centered at the sweet spot center. If you slide left or right, the sound is consistent; treble or tonal balance changes are small / subtle. But if you move up or down, the change is quite dramatic. Stand up, or sit on the floor, and it goes dead. The size of the speaker means normal size people sitting in normal chairs, the head's right about half-way up the tweeter, the treble focus point. That's where I listen and measure it, optimized for flat well balanced frequency response.

Funny related story. When watching movies my wife had a problem hearing dialog, kept asking me, "what did he/she say?". Turns out she was laying down on the couch while watching. I told her to try sitting up straight, see if it sounded more clear. She did, no more problem. Having her head just a foot or two higher made such a significant difference.

I've owned these speakers for 25 years, I used to think this effect was some kind of floor/ceiling interaction - bass boost from getting your head closer to the walls. That may be a contributing factor, but after reading that article I realize much of it is the vertically oriented line tweeter.

 

[RetroStereo]

Back in the early spring of '84, I got an invite to a performance of the Guarneri quartet at a private home in Alexandria VA sponsored by Myer Emco, a high-end audio equipment chain local to the Washington DC area, and some equipment manufacturers. I arrived about 15 minutes early to find the musicians already playing, ensconced in a musicians' gallery above the entrance to a ballroom. There were about 15 people already there when I arrived. Within maybe about 45 minutes the attendees numbered about 250.

As the musicians continued playing Vivaldi's Summer, someone took to a microphone to thank everyone for coming and to introduce the musicians. As each musician's name was called, he set down his instrument, stood and bowed to the audience.

However, the music never stopped!!! We had all been fooled. As the last musician took his bow, curtains were withdrawn on either side of the gallery, revealing a pair of Martin Logan's original monolith speakers, a Revox R2R recorder, several mics on stands and the unmistakable glow of McIntosh amplifier VU meters.

Apparently. The musicians had arrived several hours earlier and recorded about 90 minutes of music before anyone arrived. Then, just before the 1st arrivals, the sound system was switched on and the musician pretended to be playing what they had just recorded.

I think both the choice of venue and the choice of a string quartet and musical selections contributed greatly to the success of the trick. I suspect several dozen pairs of monoliths were ordered that day. I still don't know how I scored an invite. I could barely afford the time off and transportation cost to attend. But I'm glad I did. I'll never forget the experience.

 

[Purité Audio]

Edison used the very same demonstration as have many others.

Is It Live or Is It Edison? | Now See Hear!

Today’s entry is a guest post by Jan McKee, Reference Librarian, Recorded Sound Research Center. I have always wondered about the Edison tone tests. Is it really possible that an audience could not tell the difference between an Edison Diamond Disc being played on a phonograph and the live...

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Keith

 

[Sir Sanders Zingmore]

Back in the early spring of '84, I got an invite to a performance of the Guarneri quartet at a private home in Alexandria VA sponsored by Myer Emco, a high-end audio equipment chain local to the Washington DC area, and some equipment manufacturers. I arrived about 15 minutes early to find the musicians already playing, ensconced in a musicians' gallery above the entrance to a ballroom. There were about 15 people already there when I arrived. Within maybe about 45 minutes the attendees numbered about 250.

As the musicians continued playing Vivaldi's Summer, someone took to a microphone to thank everyone for coming and to introduce the musicians. As each musician's name was called, he set down his instrument, stood and bowed to the audience.

However, the music never stopped!!! We had all been fooled. As the last musician took his bow, curtains were withdrawn on either side of the gallery, revealing a pair of Martin Logan's original monolith speakers, a Revox R2R recorder, several mics on stands and the unmistakable glow of McIntosh amplifier VU meters.

Apparently. The musicians had arrived several hours earlier and recorded about 90 minutes of music before anyone arrived. Then, just before the 1st arrivals, the sound system was switched on and the musician pretended to be playing what they had just recorded.

I think both the choice of venue and the choice of a string quartet and musical selections contributed greatly to the success of the trick. I suspect several dozen pairs of monoliths were ordered that day. I still don't know how I scored an invite. I could barely afford the time off and transportation cost to attend. But I'm glad I did. I'll never forget the experience.

Impressive!
By that I mean, it seems to have been an impressive display of the power of sighted bias.

 

[RetroStereo]

Impressive!
By that I mean, it seems to have been an impressive display of the power of sighted bias.

Very true; however the sound quality was pretty much state of the art at the time. And a string quartet falls right into an electrostat's sweet spot.