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Page 5
Quest User's Manual
The Electrostatic Concept
How can sound be reproduced by something that you are
able to see through? Electrostatic energy makes this
possible.
Where the world of traditional loudspeaker technology
deals with cones, domes, diaphragms and ribbons that are
moved with magnetism, the world of electrostatic loud-
speakers deals with charged electrons attracting and
repelling each other.
To fully understand the electrostatic concept, some back-
ground information will be helpful. Remember when you
learned, in a science or physics class, that like charges
Magnet
An Electromagnetic TransducerAn Electromagnetic Transducer
An Electromagnetic TransducerAn Electromagnetic Transducer
An Electromagnetic Transducer
Surround Cone
Dust Cap
Voice Coil Former
Magnet Assembly
Magnetic GapVoice Coil
Basket Assembly
Figure 2.Figure 2.
Figure 2.Figure 2.
Figure 2. Cut away view of a typical moving coil driver.
Notice the complexity due to the high number of parts.
music. This technique is known as push-pull operation and
is a major contributor to the sonic purity of the electrostatic
concept due to its exceptional linearity and low distortion.
Since the diaphragm of an electrostatic speaker is uni-
formly driven over its entire area, it can be extremely light
and flexible. This allows it to be very responsive to tran-
sients, thus perfectly tracing the music signal. As a result,
great delicacy, nuance and clarity is possible. When you
look at the problems of traditional electromagnetic drivers,
you can easily see why this is so beneficial. The cones and
domes which are used in traditional electromagnetic
drivers cannot be driven uniformly because of their design.
Spider
Cones are driven only at the
apex. Domes are driven at
their perimeter. As a result,
the rest of the cone or dome
is just "along for the ride". The
very concept of these drivers
require that the cone or dome
be perfectly rigid, damped
and massless. Unfortunately
these conditions are not
available in our world today.
To make these cones and
domes move, all electromag-
netic drivers must use voice
coils wound on formers,
spider assemblies, and
surrounds to keep the cone
or dome in position.
See
Figure 2.
These pieces, when
combined with the high mass
of the cone or dome materials
used, make it an extremely
complex unit with many
weaknesses and potential for
failure. These faults contrib-
ute to the high distortion
products found in these
drivers and is a tremendous
disadvantage when you are
trying to change motion as
quickly and as accurately as
a loudspeaker must (40,000
times per second!).
repel each other and opposite
charges attract each other?
Well, this principle is the
foundation of the electrostatic
concept.
An electrostatic transducer
consists of three pieces: the
stators, the diaphragm and the
spacers.
See Figure 1
. The
diaphragm is what actually
moves to excite the air and
create music. The stator's job is
to remain stationary, hence the
word stator, to provide a
reference point for the moving
diaphragm. The spacers
provide the diaphragm with a
fixed distance in which to move
between the stators.
As your amplifier sends music
signals to an electrostatic
speaker, these signals are
changed into two high-voltage
signals that are equal in
strength but opposite in
polarity. These high voltage
signals are then applied to the
stators. The resulting electro-
static field, created by the
opposing high voltage on the
stators, works simultaneously
with and against the dia-
phragm, consequently moving
it back and forth, producing
An Electrostatic TransducerAn Electrostatic Transducer
An Electrostatic TransducerAn Electrostatic Transducer
An Electrostatic Transducer
Stator
Spacer
Diaphragm
Figure 1Figure 1
Figure 1Figure 1
Figure 1. Cut away view of an electrostatic transducer.
Notice the simplicity due to minimal parts usage.