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Page 5 Sequel II 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, diaphrams 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
background information will be helpful. Remember when
you learned, in a science or physics class, that like charges
repel each other and opposite charges attract each other?
Magnet
An Electromagnetic Transducer An Electromagnetic Transducer
An Electromagnetic Transducer An Electromagnetic Transducer
An Electromagnetic Transducer
Surround Cone
Dust Cap
Voice Coil Former
Magnet Assembly
Magnetic Gap Voice 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.
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
uniformly driven over its entire area, it can be extremely
light and flexible. This allows it to be very responsive to
transients, thus perfectly tracing the music signal. As a
result, great delicacy, nuance and clarity is possible.
When you look at the problems of traditional electromag-
netic 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. Cones are driven only at the apex.
Spider
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 materi-
als used, make it an ex-
tremely complex unit with
many weaknesses and
potential for failure. These
faults contribute 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!).
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
music. This technique is known
as push-pull operation and is a
An Electrostatic Transducer An Electrostatic Transducer An Electrostatic Transducer An Electrostatic Transducer An Electrostatic Transducer
Stator
Spacer
Diaphragm
Figure 1 Figure 1
Figure 1 Figure 1 Figure 1. Cut away view of an electrostatic transducer.
Notice the simplicity due to minimal parts usage.