Electrostatic Speakers - Quad, Martin Logan Speakers, Magnepan
An overview of Electrostatic Speakers, with a look at offerings from different makers such as Quad, Martin Logan, and Magnepan...
Electrostatics sound like nothing else, because they operate on a completely different principle to conventional speakers.
They also look very different! They can be over six feet high, two or three feet wide, but only a few inches deep from front to back.
There are only a handful of companies making electrostatic speakers, making them an "enthusiast's choice". But before we look at who these brave manufacturers are, let's take a look at what makes electrostatics different...
An electrostatic speaker uses a thin, light polyester film with exceptional mechanical properties, such as Mylar. This is suspended between two electrically conductive grids of the same size.
There's a small air gap between the film and the grids. The polyester film is usually coated with a conducting medium such as graphite.
A high voltage is supplied to the polyester film, and it is held at a DC potential of several kilovolts with respect to the grids. The grids are then fed the electrical audio signal. Front and rear grid are driven in antiphase.
As a result, a uniform electrostatic field is produced between both grids. This causes an electrostatic force on the charged polyester film, and it vibrates in proportion to the audio signal, driving the air on either side of it.
- Advantages...
Extremely low distortion, and a fantastic frequency response. Musical transparency is much better than in normal speakers, because the vibrating surface has much less mass than most other drivers. Acoustic instruments, pianos and voices sound awesome.
- Disadvantages:
Electrostatics are BIG. You'll need a big room to let them breathe, at least 600 sq. ft., with 8 ft ceilings, and 6 ft. of space behind the speakers.
They also typically need a lot of power to drive them.
Electrostatic speakers can also lack bass punch. Although the bass is weaker than normal speakers, it's usually higher quality than on non-electrostatics
To sum up, electrostatics are fantastic if you enjoy classical music, especially smaller ensembles. To get the full 'Wagner' experience, consider a hybrid design, which incorporates a conventional subwoofer to augment the lowest frequencies.
So, what are your choices?
Quad Electrostatic Speakers
This famous manufacturer from the U.K. has been making electrostatic speakers for 60 years. The current top model is the ESL 2905.
Given enough power, (a McIntosh 2102 valve amp is perfect), these Quads can produce a surprising bass performance without a sub-woofer, as well as producing the mid-range clarity and high-frequency sparkle typical of previous models.
In terms of size, they are also smaller than other electrostatics. A lot of Bang for your Buck!
Martin Logan Speakers
This is a respected american company that only makes electrostatics. Their CLX model costs around twice the Quad ESL2905.
The Martin Logans are actually hybrid speakers, as they incorporate sub-woofers to augment the bass. They can go louder than the Quads, but you'll need some serious amplifier muscle from (say) Mark Levinson or Krell to do the job.
By the way, you'll need two people to install these puppies, as they weigh 152lb. each!
Magnepan
Magneplanar speakers by Magnepan are, strictly speaking, NOT electrostatics, but "ribbon" speakers.
They use a vanishingly thin alumimium ribbon suspended between two permanent magnets for mid and low frequencies, and a mylar diaphragm for high frequencies.
The basic layout is similar to electrotatics, but they use magnetic fields rather than electrostatic fields.
The result is astonishing: many reviewers claim that the sound is the most realistic reproduction of instruments they have ever heard.
Interestingly, Magneplanar speakers are less expensive than full-on electrostatics, for a given level of resolution and volume.
Sound Lab
This is a very small business, hand-building some of the best electrostatic speakers available.
All Sound Labs speakers are very solidly built - and heavy, due to the frame and base. The Millenium -1 weighs 176lb. each! Their Millenium-1 has that astonishingly vibrant, life-like sound production of all electrostatics, but with an extra crystalline clarity and a sense of "air".
It reproduces string quartets with absolute solidity, piano with "bite" to the notes, and a full orchestra in glorious technicolor! Definitely worth an audition if your budget allows.
You might also be interested in active loudspeakers, another different type of speaker.
There are also electrostatic headphones, which use the same principle.
