Subwoofer Frequency Characteristics; Advanced Yamaha Active Servo Technology Ii - Yamaha NS-SW500 Bedienungsanleitung

Subwoofer frequency characteristics

The figures below show the optimum adjustment of each
control and the frequency characteristics when the
subwoofer is combined with a typical front speaker system.
dB HIGH CUT 40 Hz
HIGH CUT 90 Hz
90
HIGH CUT 140 Hz
80
70
60
50
40
20 50 100 200 500Hz
7
En
■
When combined with 10 cm (4") or 13 cm (5")
acoustic suspension, 2-way system front
speakers
dB
PHASE
90
80
(70 Hz) (REV)
70
60
50
40
20
Frequency response graph*
■
When combined with 20 cm (8") or 25 cm (10")
acoustic suspension, 2-way system front
speakers
dB
PHASE
90
80
(50 Hz) (REV)
70
60
50
40
20
Frequency response graph*
* This diagram does not depict actual frequency
response characteristics.
ACTIVE SERVO TECHNOLOGY II
In 1988, Yamaha brought to the marketplace speaker
systems utilizing YST (Yamaha Active 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.
Front As this technology uses speaker units controlled by the
speaker
negative impedance drive of the amplifier and resonance
generated between the speaker cabinet volume and port, it
creates more resonant energy (the "air woofer" concept)
50 100 200 500Hz
than the standard bass reflex method. This allows for bass
reproduction from much smaller cabinets than was
previously possible.
Yamaha's newly developed Advanced YST II adds many
refinements to Yamaha Active Servo Technology,
allowing better control of the forces driving the amplifier
and speaker. From the amplifier'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.
Front
speaker
50 100 200 500Hz
High-
amplitude
bass sound
ADVANCED YAMAHA
Cabinet
Port
Air woofer
(Helmholtz resonator)
Advanced impedance
Converter
Active Servo
Processing
Amplifier
Signals of low amplitude
Signals