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15

English

ACTIVE SERVO TECHNOLOGY

The theory of Active Servo Technology is based upon two
major factors, the Helmholtz resonator and negative-
impedance drive.  Active Servo Processing 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 the Helmholtz resonance theory, be output
from this opening as waves of great amplitude if the
design is such that the size of the opening and the volume
of the cabinet are in the correct proportion to satisfy a
certain ratio.
In order to accomplish this, moreover, the amplitudes
within the cabinet must be both precise and of sufficient
power because these amplitudes must overcome the
“load” presented by the air that exists within the cabinet.

Thus it is this problem that is resolved through the
employment of a design in which the amplifier functions to
supply special signals.  If the electrical resistance of the voice
coil could be reduced to zero, the movement of the speaker
unit would become linear with respect to signal voltage, and,
to accomplish this, a special negative-impedance output-drive
amplifier for subtracting output impedance of the amplifier is
used.
By employing negative-impedance drive circuits, the amplifier
is able to generate precise, low-amplitude low-frequency
waves with superior damping characteristics, and 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 with the Helmholtz resonator, reproduce an extremely
wide range of frequencies with amazing sound quality and
less distortion.
The features described above, then, are combined to be the
fundamental structure of the Active Servo Technology.

REMOVING THE FRONT GRILLE

The front grille is fastened to the enclosure at four points,
and can be removed if desired. To remove the grille, first
hold the bottom of the grille and unfasten the lower part of
the grille by pulling it gently, and then hold both sides of the
grille and slowly pull straight away from the speaker. To
reattach, line up the four pegs on the inside surface of the
grille with the four corresponding holes on the speaker and
push gently.

Note
When the grille is removed, take care not to touch the
speaker unit with your hands or to exert excessive force
with tools.

Signals of low amplitude

Air woofer
(Helmholtz resonator)

Negative-impedance
output drive

High-
amplitude
bass
sound

Signals

Active Servo
Processing Amplifier

Cabinet

Port

Summary of Contents for YST-SW300

Page 1: ...stem Enceinte pour très basses fréquences de traitement à asservissement actif YST SW300 Active Servo Technology Thank you for selecting this YAMAHA Subwoofer System Nous vous remercions d avoir porté votre choix sur cette enceinte pour très basses fréquences YAMAHA ...

Page 2: ...ce receptacles and the point where they exit from the unit 12 Cleaning The unit should be cleaned only as recommended by the manufacturer 13 Nonuse Periods The power cord of the unit should be unplugged from the outlet when left unused for a long period of time 14 Object and Liquid Entry Care should be taken so that objects do not fall into and liquids are not spilled into the inside of the unit 1...

Page 3: ... determined by turning the unit OFF and ON please try to eliminate the problem by using one of the following measures Relocate either this product or the device that is being affected by the interference Utilize power outlets that are on different branch circuit breaker or fuse circuits or install AC line filter s In the case of radio or TV interference relocate reorient the antenna If the antenna...

Page 4: ...oducing a super bass sound Be careful not to put a hand or some objects into the port otherwise it may give you an electric shock or give this unit a damage or cause a fire 14 Voltage Selector General Model only The voltage selector on the rear panel of this unit must be set for your local main voltage BEFORE plugging into the AC main supply Voltages are AC 110 120 220 240V 50 60 Hz IMPORTANT Plea...

Page 5: ...ncy cut off point HIGH CUT control Moreover the PHASE switch allows you to select the best sound quality for various listening conditions A newly employed AUTO POWER ON OFF switch saves you the trouble of pressing the POWER switch when turning the power on and off If using one subwoofer it is recommended to place it on the outside of either the right or the left main speaker See fig If using two s...

Page 6: ...TO SPEAKER TERMINALS OF THE AMPLIFIER Disconnect your main speakers from the amplifier and connect them to this unit To connect one unit only To connect two units CONNECTIONS OUTPUT TO SPEAKERS INPUT1 FROM AMPLIFIER INPUT2 H P F OUTPUT PHASE NOM REV 50Hz I00Hz 80Hz ON OFF AUTO POWER OUTPUT TO SPEAKERS INPUT1 FROM AMPLIFIER INPUT2 H P F OUTPUT PHASE NOM REV 50Hz I00Hz 80Hz ON OFF AUTO POWER OUTPUT ...

Page 7: ...ould damage this unit your amplifier and or speakers How to Connect Red positive Black negative 1Unscrew the knob 2Insert the bare wire Remove approx 5mm 1 4 insulation from the speaker wires 3Tighten the knob and secure the wire Banana Plug connections are also possible except for U K and Europe models Simply insert the Banana Plug connector into the corresponding terminal Connecting to this unit...

Page 8: ...uld not be connected to the OUTPUT terminals on the rear panel of this unit If connected they will not produce sound When connecting to a monaural line output terminal of the amplifier connect to either the left or right INPUT 2 terminal 8 PRE OUT SPLIT SUBWOOFER LOW PASS SUBWOOFER OUTPUT TO SPEAKERS INPUT1 FROM AMPLIFIER INPUT2 H P F OUTPUT PHASE NOM REV 50Hz I00Hz 80Hz ON OFF AUTO POWER INPUT2 H...

Page 9: ...ain speakers reproduce high frequencies only This will make the whole sound quality clear by preventing sound muddying between the main speakers and this unit This connection can be made if your amplifier has PRE OUT and MAIN IN terminals or you are using separate amplifiers pre amplifier and main amplifier To connect one unit only MAIN IN PRE OUT OUTPUT TO SPEAKERS INPUT1 FROM AMPLIFIER INPUT2 H ...

Page 10: ...0Hz I00Hz 80Hz ON OFF AUTO POWER This unit This unit Pin plug cords Right speaker Left speaker Amplifier To AC outlet To AC outlet To connect two units Switching the H P F OUTPUT switch After the connection is made select the desired frequency point 50 Hz 80 Hz or 100 Hz with the H P F OUTPUT switch Only frequencies higher than the selected frequency are output from the H P F OUTPUT terminals Norm...

Page 11: ...ntrol Used to increase or decrease the low frequency response Turn this clockwise toward the MOVIE position to increase the low frequency response Turn this counterclockwise toward the MUSIC position to decrease the low frequency response 6 OUTPUT TO SPEAKERS terminals Can be used for connections with the main speakers These terminals send signals output from the amplifier to the main speakers dir...

Page 12: ...ion will not operate There may be a case that the power turns on unexpectedly by sensing noise from other appliances If it occurs set the AUTO POWER ON OFF switch to the OFF position This function is available only when the power of this unit is on by setting the POWER switch 2 to on 9 PHASE switch Normally this switch is to be set to the normal NOM position However according to your speaker syste...

Page 13: ...r s volume control For adjusting the VOLUME control the HIGH CUT control and the PHASE switch refer to FREQUENCY CHARACTERISTICS on the next page For effective adjustment of the HIGH CUT control First set this control at about the main speakers rated minimum reproduceable frequency Then turn up the VOLUME control gradually and set it at a level where you can obtain a little more bass effect than w...

Page 14: ... This unit s frequency characteristics When combined with a 4 or 5 acoustic suspension 2 way system PHASE Set to the reverse REV position When combined with an 6 or 8 acoustic suspension 2 way system PHASE Set to the reverse REV position VOLUME 0 I0 HIGH CUT 40Hz I40Hz VOLUME 0 I0 HIGH CUT 40Hz I40Hz 20 50 100 200 500Hz 40 50 60 70 80 90 dB HIGH CUT 40 Hz HIGH CUT 90 Hz HIGH CUT 140 Hz 20 50 100 2...

Page 15: ...l negative impedance output drive amplifier for subtracting output impedance of the amplifier is used By employing negative impedance drive circuits the amplifier is able to generate precise low amplitude low frequency waves with superior damping characteristics and these waves are then radiated from the cabinet opening as high amplitude signals The system can therefore by employing the negative i...

Page 16: ...on the subwoofer or break up the parallel surface by placing bookshelves etc along the walls Turn the POWER switch on Increase the level of input signal on the source Increase the level of input signal on the source Move this unit farther away from such equipment and or change the position of connected speaker cables Otherwise do not use the automatic power ON function of this unit If the unit fai...

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