Advanced Yamaha Active Servo Technology (On The Sw-P330) - Yamaha Advanced YST NS-P330 Mode D'emploi

Advanced Yamaha Active Servo Technology (on the SW-P330)

The theory behind Yamaha Active Servo Technol-
ogy is based on two factors: the Helmholtz resonator
and negative-impedance drive. Active Servo Pro-
cessing speakers reproduce the bass frequencies
through an "air woofer," which is a port or opening
in the speaker's cabinet.
This opening is used instead of, and performs the
functions of, a woofer in a conventionally designed
speaker system.
Thus, signals of low amplitude within the cabinet
can, according to Helmholtz resonance theory, be
output from this opening as waves of great ampli-
tude if the size of the opening and the volume of the
cabinet are in proportion to satisfy a certain ratio. In
order to accomplish this, moreover, the amplitudes
within the cabinet must be both precise and of suffi-
cient power because these amplitudes must over-
come the "load" presented by the air in the cabinet.
This problem is resolved by a design in which the
amplifier supplies special signals. If the electrical
resistance of the voice coil could be reduced to zero,
the movement of the speaker unit would become lin-
ear with respect to signal voltage. To accomplish
this, the system utilizes a special negative-imped-
ance output-drive amplifier that subtracts the output
impedance of the amplifier.
High-amplitude
bass sound
By employing negative-impedance drive circuits, the
amplifier is able to generate precise, low-amplitude,
low frequency waves with superior damping charac-
teristics.
These waves are then radiated from the cabinet
opening as high-amplitude signals. The system can,
therefore, by employing the negative-impedance
output drive amplifier and a speaker cabinet featur-
ing a Helmholtz resonator, reproduce an extremely
wide range of frequencies with outstanding sound
quality and low distortion.
The features described above combine to create the
fundamental structure of conventional Yamaha
Active Servo Technology.
Our new Active Servo Technology — Advanced
Yamaha Active Servo Technology — adopts
Advanced Negative Impedance Converter (ANIC)
circuits, which allow the conventional negative
impedance converter to dynamically vary to select
an optimum value for speaker impedance variation.
With these new ANIC circuits, Advanced Yamaha
Active Servo Technology provides a more stable
performance and improved sound pressure com-
pared to conventional Yamaha Active Servo Tech-
nology, resulting in more natural and dynamic bass
reproduction.
Air woofer
Cabinet
(Helmholtz resonator)
Port
Advanced Negative
impedance Converter
Active Servo
Processing
Amplifier
Signals of low amplitude
Placing the Speakers
Signals
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