Genesis I.C.E. 928 - Manual (Page 13)

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~ДлздмнЙ=СбЗЙдбну™
The Technology
The Servo Advantage
Very few loudspeakers use servo drive, either because most designers
think that it is too difficult to design, too expensive, or because of the
extraordinary demands a servo system makes on the amplifier and the
transducer. However, the Chief Scientist of Genesis, Arnie Nudell, first
introduced the servo system in the legendary Infinity Servo Statik One
in 1968(!) – so we know how to design and build servo systems.
The concept of our servo bass system is an easy one to understand: It
employs, an accelerometer as a sensor, to constantly monitor the
movement of the woofer cone and instantaneously compares it to the
input signal. This comparison circuit instantly identifies any deviation
from the ideal and instantaneously applies a corrective signal to
compensate for any deviation, resulting in the virtual elimination of the
inherent distortion of the woofer.
As an example, when you have a high-impact, low-bass signal that
starts and stops suddenly (for example a tympani), the inertia of the
woofer cone makes it slow to start moving, and then after it is moving,
the momentum of the cone makes it continue to move after the signal
has stopped.
The sonic result is overhang, bloat, lack of tautness and definition, and
a blurring of dynamic impact. With the servo system, the circuit senses
that the woofer is not moving as fast as it should, and it applies more
current to make it move faster. When the signal stops, it detects that
the woofer is still moving when it shouldn’t and applies a counter-signal
to stop the woofer faster and more effectively than normal circuitry
would.
Thus, the servo-drive reduces distortion and improves transient
response by making the woofer seem massless. Typical non-servo
woofer systems have distortion levels that exceed 10% at even
moderate levels. The Genesis servo bass system reduces this
distortion to below one percent at almost any output level. Moreover, it
drives the woofer to constant acceleration which makes its frequency
response perfectly flat!
500W Class-D Switching Amplifier
The servo system places extraordinary demands on the amplifier
because the system uses enormous amounts of current to make the
woofer follow the signal. This means that the amplifier used must
deliver huge amounts of clean power.