Living with an Acoustical Line Source
The Sound Lab Millieneum
The underlying theory of electrostatic speakers is actually quite straight forward. The laws of physics teach that "like" electrical charges repel one-another and "unlike" electrical charges attract one-another. But this is easy to say and much more difficult to execute. First, stretch a very thin membrane on a rigid frame. Then coat it with a low-mass electrically-conductive substance. After that fabricate stiff flat electrodes called stators and then insulate them to prevent discharge. The audio signal applied to each stator is identical with the exception of phase, one signal is 180 degrees out of phase with the other. So as the signal voltage on one stator increases positively, it attracts the negative electron charge on the membrane. The signal voltage on the other stator is increasing negatively and, hence, repels the charge on the membrane. Thus, a "push-pull" force is exerted on the membrane. When the audio signal reverses, the push-pull force also reverses. Since the membrane is compliant, the push-pull electrostatic force applied to it causes it to move. Thus, air is moved and sound is created in the image of the electrical driving force. Wallah it works, straight from Mr West and his site with a bit of paraphrasing.
So what do you get? Well imagine if you would a string running from the floor to ceiling of your listening room, and then imagine that if you plucked the string it produced full frequencies with superb transient speed, no coloration, openess, detail, and a coherence of the sound only produced by a single driver. Oh yes, and we can cut the string and still keep everthing since the speaker although large, in my case about 6 ft tall is not as tall as the whole room. You end up with an Acoustical Line Source.
So what sets Dr. Roger West's speakers apart from the pack? Well, he facets the "curved" face, putting many smaller flat panels together to form the panel needed for quality sound, this sectioning not only allows for deep bass (mine go to 30hz) it also eliminates so called one note bass ELS so often have a problem with if they can play bass at all or need to use a supplemental bass system. There are many other innovative technique's that the Sound Lab company patents and incorporates in their speakers, if you interested check it out at http://www.soundlab-speakers.com/products.htm
Of course nothing can be perfect. These speakers need tremendous power to work properly and like all high end products they are so complex and sensitive that changes to air temp. humidity, and environment do effect the bias charge of the panel, so you have to be willing to adjust the bias as needed and keep a dehumidifier in your room. A small price to pay as far as I am concerned for the sound you get.
Now speaking of power, the speaker has measured to dip as low .5 ohm during treble passages. The bass impedance curve is also not all that smooth. As many know this caused me to have to let my beloved BAT amps go. In their place are now Wolcott Presence 220 watt monobloc, with, yep variable damping of both high or low frequencies to meet your need, an amazing design to say the least. Eight excellent EL-34 power tubes with some innovative driver design and an auto-bias circuit, all add up to a terriffic tube amp. As we know.........TUBES RULE.
I have included some shots for you to see the new amps, cant get the speaker shots up right now, but I think I posted them in another thread. No doubt that an audio trip with an ELS speaker of your choice is highly recommended, but in particular Sound Lab, one of the most unknown yet one of the best Electro-Stats ever built.