Advanced Yamahaactive Serve Technology Ii - Yamaha YST SW012 Owner's Manual

Advanced YamahaActiveServo Technology II
In 1998, Yamaha brought to the marketplace
speaker systems utilizing YST (YamahaActive Servo
Technology) to give powerful, high quality bass
reproduction. This technique uses a direct
connection between the amplifier and speaker,
allowing accurate signal transmission and precise
speaker control.
As this technology uses speaker units controlled by
the negative hnpe&mce drive of the amplifier and
reson_mce generated between the speaker cabinet
volume and port, it creates morn resonant energy
(the "air woofer' concept) than the standard bass
reflex method. This allows for bass reproduction
from much smaller cabinets them was previously
possible.
Yamaha's newly developed Advmlced YST II adds
many refinements to Yam_flm Active Servo
Technology, allowing better control of the forces
driving the amplifier and speaker. From the ampfi-
fier's point of view, the speaker impedance changes
depending on the sound frequency. Yamaha
developed a new circuit design combining
negative-impedance and constant-current drives,
which provides a more stable performance and
clear bass reproduction without any murkiness.
High-amplitude
bass sound
_Cabinet
Port
\
I
Signals of low amplitude
Air woofer
(Helmholtz resonator)
Advanced impedance
Converter
Active Servo I
Processing _,_
Amplifier
Signals