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#1
Posted to rec.audio.high-end
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Electrostatics, anyone?
My first good stereo speakers were the original Quad Electrostatic
Loudspeakers. I thought they were remarkable, despite the lack of any really deep bass and some rolled-off highs. On voice, they are the only speakers that ever made me jump thinking someone else was in the room. About a decade later, I splurged on a double-pair of KLH-9s. Better in some, but not all, ways. Over the years, I heard Acoustat, Koss, Beveridge (sp?), Sound Lab ESLs, and more recent Quad models. The original Martin-Logan CLS created an amazing holographic image, but totally transparent-but without bass or a palpable sense of acoustic power heard in a good concert hall. All of these ESLs, seemed to me to have a limited dynamic range and lose their transparency when pushed by large orchestral works. Nonetheless, I was always attracted to certain ESL characteristics and remain so, even though I now have Infinity speakers with EMIT and EMIM drivers. Is Martin-Logan the ESL manufacturer left standing? Has anyone heard (or heard of) and ESL that finally minimized the limits I described above? Ed Presson |
#2
Posted to rec.audio.high-end
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Electrostatics, anyone?
For a number of years, I kept Acoustat speakers along with a pair of AR11s.=
Then I heard a pair of AR9s, and the 11s went away, the Acoustats went to = my brother who has them to this day.=20 We moved into a house with no room for the 9s, they were replaced by a pair= of M5s. Then we moved into a house with a 27 x 17 x 10 library at about th= e same time I heard a pair of Magnepans. That was 9 years ago this month.= =20 Today, the main system is a pair of MG-IIIs with the ribbon tweeter and the= external crossovers. I will never look back. If you like the soundstage fr= om planar speakers, but do not like the rolled off top and bottom, look int= o Maggies. No sub-woofer needed. No, they do not have the bass of an AR9, b= ut they can shake the room. The highs, on the other hand, are unsurpassed. = Still made in the USA. By the way, the Acoustats sound thin by comparison.= =20 Fair Warning: They are power-pigs, even more so than my pair of AR3as.=20 Peter Wieck Melrose Park, PA=20 |
#3
Posted to rec.audio.high-end
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Electrostatics, anyone?
On 4 Mar 2017 12:15:28 GMT, "Ed Presson" wrote:
All of these ESLs, seemed to me to have a limited dynamic range and lose their transparency when pushed by large orchestral works. I have always wondered whether this seemingly universal impression of electrostatics has been caused by their being driven improperly. Conventional wisdom is that electrostatics are voltage-driven devices, but strict application of Gauss' and Coulomb's Laws indicates that they are actually charge-driven. When driven by voltage, the force on the diaphragm changes as excursion changes. When driven by charge, the force is independent of excursion. |
#4
Posted to rec.audio.high-end
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Electrostatics, anyone?
On Saturday, March 4, 2017 at 5:24:46 AM UTC-8, Greg Berchin wrote:
On 4 Mar 2017 12:15:28 GMT, "Ed Presson" wrote: All of these ESLs, seemed to me to have a limited dynamic range and lose their transparency when pushed by large orchestral works. I have always wondered whether this seemingly universal impression of electrostatics has been caused by their being driven improperly. Conventional wisdom is that electrostatics are voltage-driven devices, but strict application of Gauss' and Coulomb's Laws indicates that they are actually charge-driven. When driven by voltage, the force on the diaphragm changes as excursion changes. When driven by charge, the force is independent of excursion. can you tell me your impression of what electrostats would sound like if somehow they were driven differently? |
#5
Posted to rec.audio.high-end
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Electrostatics, anyone?
On 6 Mar 2017 12:56:47 GMT, abbeynormal wrote:
can you tell me your impression of what electrostats would sound like if somehow they were driven differently? Beats me. I have found that trying to predict how something will sound by analyzing the math alone generally doesn't work very well. I can say this, though. High school physics tells us that, when driven by voltage, the force on the diaphragm is: (Vbias+Vaudio)^2 (Vbias-Vaudio)^2 F = e0A--------------------- - e0A---------------------, 2[(|dFR|/2)-deltaD]^2 2[(|dFR|/2)+deltaD]^2 where e0 = the permittivity of free space A = the area of the diaphragm Vbias = the bias voltage applied to the stators Vaudio = the audio signal voltage |dFR| = the distance (gap) between the front and rear stators deltaD = how far the diaphragm has moved from its center rest position Note that the force changes as deltaD changes, i.e., when the diaphragm moves closer to one of the stators and farther from the other, even when Vbias and Vaudio are held constant. But when driven by charge, the force on the diaphragm is: |qbias*qaudio| |F| = 2-------------- e0A where qbias = the bias charge applied to the stators qaudio = the charge applied by the audio signal and the direction of the force can be determined by context. Note that the force is constant as long as the charges are constant, regardless of the position of the diaphragm. Now, how do we design a charge amplifier? In theory, it's not all that difficult. Hint: electrostatic loudspeakers are capacitors, capacitors store charge, and current integrated over time equals charge. |
#6
Posted to rec.audio.high-end
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Electrostatics, anyone?
In article ,
Greg Berchin wrote: On 6 Mar 2017 12:56:47 GMT, abbeynormal wrote: can you tell me your impression of what electrostats would sound like if somehow they were driven differently? Beats me. I have found that trying to predict how something will sound by analyzing the math alone generally doesn't work very well. I can say this, though. High school physics tells us that, when driven by voltage, the force on the diaphragm is: (Vbias+Vaudio)^2 (Vbias-Vaudio)^2 F = e0A--------------------- - e0A---------------------, 2[(|dFR|/2)-deltaD]^2 2[(|dFR|/2)+deltaD]^2 where e0 = the permittivity of free space A = the area of the diaphragm Vbias = the bias voltage applied to the stators Vaudio = the audio signal voltage |dFR| = the distance (gap) between the front and rear stators deltaD = how far the diaphragm has moved from its center rest position Note that the force changes as deltaD changes, i.e., when the diaphragm moves closer to one of the stators and farther from the other, even when Vbias and Vaudio are held constant. But when driven by charge, the force on the diaphragm is: |qbias*qaudio| |F| = 2-------------- e0A where qbias = the bias charge applied to the stators qaudio = the charge applied by the audio signal and the direction of the force can be determined by context. Note that the force is constant as long as the charges are constant, regardless of the position of the diaphragm. Now, how do we design a charge amplifier? In theory, it's not all that difficult. Hint: electrostatic loudspeakers are capacitors, capacitors store charge, and current integrated over time equals charge. Some electrostatic speakers use a material with extremely high surface restivity for the diaphragm (made e.g. by lightly rubbing the plastic sheet with a carbon-dust-coated pad). The claim is that doing it that way puts the diaphragm in a "constant charge" mode (IIRC). Isaac |
#7
Posted to rec.audio.high-end
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Electrostatics, anyone?
On 7 Mar 2017 11:35:57 GMT, isw wrote:
Some electrostatic speakers use a material with extremely high surface restivity for the diaphragm (made e.g. by lightly rubbing the plastic sheet with a carbon-dust-coated pad). The claim is that doing it that way puts the diaphragm in a "constant charge" mode (IIRC). Yes, I have heard that. But why approximate it when you can achieve it explicitly through design? |
#8
Posted to rec.audio.high-end
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Electrostatics, anyone?
I have not heard any speakers that impressed me more than a [1982] pair of =
Maggie tympani IIIs [driven by giant monoblock class A's each the size of a= small refrigerator and as efficient at heating the room as a fireplace] th= at utterly transported me to the cathedral in a good direct-disk pipe organ= recording. |
#9
Posted to rec.audio.high-end
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Electrostatics, anyone?
On Sunday, March 5, 2017 at 7:36:25 AM UTC-5, abbeynormal wrote:
I have not heard any speakers that impressed me more than a [1982] pair o= f Maggie tympani IIIs [driven by giant monoblock class A's each the size of= a small refrigerator and as efficient at heating the room as a fireplace] = that utterly transported me to the cathedral in a good direct-disk pipe org= an recording. There is that. I often wonder why those who have the space do not simply go= to Maggies and have done with it. Even new, they are certainly reasonably = priced, are entirely remarkable and in my direct experience, very rugged.= =20 http://www.integracoustics.com/MUG/M.../speakers.html =20 Is a link not quite to the beginning of time, but close and far enough. The= specifications given are very conservative, again in my direct experience. Peter Wieck Melrose Park, PA |
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