Yamaha YST-SW015 User Manual

YST-SW015

Subwoofer System

U B

OWNER’S MANUAL

IMPORTANT SAFETY INSTRUCTIONS

1 Read these instructions.

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

CAUTION: TO REDUCE THE RISK OF
ELECTRIC SHOCK, DO NOT REMOVE
COVER (OR BACK). NO USER-SERVICEABLE
PARTS INSIDE. REFER SERVICING TO
QUALIFIED SERVICE PERSONNEL.

• Explanation of Graphical Symbols

The lightning flash with arrowhead
symbol, within an equilateral triangle,
is intended to alert you to the
presence of uninsulated “dangerous
voltage” within the product’s
enclosure that may be of sufficient
magnitude to constitute a risk of
electric shock to persons.

The exclamation point within an
equilateral triangle is intended to alert
you to the presence of important
operating and maintenance
(servicing) instructions in the
literature accompanying the
appliance.

WARNING

TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE THIS APPLIANCE TO RAIN
OR MOISTURE.

IMPORTANT

Please record the serial number of this unit in the
space below.

Model:

Serial No.:

The serial number is located on the rear of the unit.
Retain this Owner’s Manual in a safe place for
future reference.

2 Keep these instructions.

3 Heed all warnings.

4 Follow all instructions.

5 Do not use this apparatus near water.

6 Clean only with dry cloth.

7 Do not block any ventilation openings. Install in

accordance with the manufacturer’s instructions.

8 Do not install near any heat sources such as radiators,

heat registers, stoves, or other apparatus (including
amplifiers) that produce heat.

9 Do not defeat the safety purpose of the polarized or

grounding-type plug. A polarized plug has two blades
with one wider than the other. A grounding type plug
has two blades and a third grounding prong. The wide
blade or the third prong are provided for your safety. If
the provided plug does not fit into your outlet, consult
an electrician for replacement of the obsolete outlet.

10 Protect the power cord from being walked on or

pinched particularly at plugs, convenience receptacles,
and the point where they exit from the apparatus.

11 Only use attachments/accessories specified by the

manufacturer.

12 Use only with the cart, stand, tripod,

bracket, or table specified by the
manufacturer, or sold with the
apparatus. When a cart is used, use
caution when moving the cart/
apparatus combination to avoid injury
from tip-over.

13 Unplug this apparatus during lightning storms or when

unused for long periods of time.

14 Refer all servicing to qualified service personnel.

Servicing is required when the apparatus has been
damaged in any way, such as power-supply cord or
plug is damaged, liquid has been spilled or objects
have fallen into the apparatus, the apparatus has been
exposed to rain or moisture, does not operate normally,
or has been dropped.

II

● Be sure to allow spaces of at least 20 cm above,
behind and on both sides of the unit.

● Do not place the following objects on this unit:
A vessel with water in it.
If the vessel falls by vibrations and water spills, it
may cause damage to the unit, and/or you may get
an electric shock.

FCC INFORMATION (for US customers only)

1. IMPORTANT NOTICE : DO NOT MODIFY THIS
UNIT!

This product, when installed as indicated in the
instructions contained in this manual, meets FCC
requirements. Modifications not expressly approved
by Yamaha may void your authority, granted by the
FCC, to use the product.

2. IMPORTANT : When connecting this product to
accessories and/or another product use only high
quality shielded cables. Cable/s supplied with this
product MUST be used. Follow all installation
instructions. Failure to follow instructions could void
your FCC authorization to use this product in the
USA.

3. NOTE : This product has been tested and found to
comply with the requirements listed in FCC
Regulations, Part 15 for Class “B” digital devices.
Compliance with these requirements provides a
reasonable level of assurance that your use of this
product in a residential environment will not result in
harmful interference with other electronic devices.

This equipment generates/uses radio frequencies
and, if not installed and used according to the
instructions found in the users manual, may cause
interference harmful to the operation of other
electronic devices.

Compliance with FCC regulations does not guarantee that
interference will not occur in all installations. If this
product is found to be the source of interference, which
can be 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 lead-in is 300 ohm ribbon
lead, change the lead-in to coaxial type cable.

If these corrective measures do not produce satisfactory
results, please contact the local retailer authorized to
distribute this type of product. If you can not locate the
appropriate retailer, please contact Yamaha Electronics
Corp., U.S.A. 6660 Orangethorpe Ave, Buena Park, CA

90620.

The above statements apply ONLY to those products
distributed by Yamaha Corporation of America or its
subsidiaries.

We Want You Listening For A Lifetime

YAMAHA and the Electronic Industries Association’s
Consumer Electronics Group want you to get the most out
of your equipment by playing it at a safe level. One that lets
the sound come through loud and clear without annoying
blaring or distortion – and, most importantly, without
affecting your sensitive hearing.

Since hearing damage from loud sounds is
often undetectable until it is too late, YAMAHA
and the Electronic Industries Association’s
Consumer Electronics Group recommend you
to avoid prolonged exposure from excessive
volume levels.

III

UNPACKING Please check to make sure all listed items are included.

Nonskid pads

For U.K. customers

If the socket outlets in the home are not suitable for the plug
supplied with this appliance, it should be cut off and an
appropriate 3 pin plug fitted. For details, refer to the
instructions described below.
Note: The plug severed from the mains lead must be
destroyed, as a plug with bared flexible cord is hazardous if
engaged in a live socket outlet.

SPECIAL INSTRUCTIONS FOR U.K. MODEL

IMPORTANT:

THE WIRES IN MAINS LEAD ARE COLOURED IN
ACCORDANCE WITH THE FOLLOWING CODE:

Blue: NEUTRAL
Brown: LIVE

As the colours of the wires in the mains lead of this
apparatus may not correspond with the coloured markings
identifying the terminals in your plug, proceed as follows:
The wire which is coloured BLUE must be connected to
the terminal which is marked with the letter N or coloured
BLACK. The wire which is coloured BROWN must be
connected to the terminal which is marked with the letter L
or coloured RED. Making sure that neither core is
connected to the earth terminal of the three pin plug.

For Canadian Customers

To prevent electric shock, match wide blade of plug to
wide slot and fully insert.

This Class B digital apparatus complies with Canadian
ICES-003.

IV

Thank you for selecting this YAMAHA Subwoofer System.

CAUTION: Read this before operating your unit.

English

Please read the following operating precautions before use.
YAMAHA will not be held responsible for any damage
and/or injury caused by not following the cautions below.

●

To assure the finest performance, please read this manual
carefully. Keep it in a safe place for future reference.

● Install this unit in a cool, dry, clean place – away from

windows, heat sources, sources of excessive vibration,
dust, moisture and cold. Avoid sources of humming
(transformers, motors). To prevent fire or electrical
shock, do not expose this unit to rain or water.

● Never open the cabinet. If something drops into the set,

contact your dealer.

● The voltage to be used must be the same as that

specified on the rear panel. Using this unit with a higher
voltage than specified is dangerous and may cause a
fire and/or electric shock.

● To reduce the risk or fire or electric shock, do not expose

this unit to rain or moisture.

● Do not use force on switches, controls or connection

wires. When moving the unit, first disconnect the power
plug and the wires connected to other equipment. Never
pull the wires themselves.

● When not planning to use this unit for a long period (i.e.

vacation, etc.), disconnect the AC power plug from the
wall outlet.

● To prevent lightning damage, disconnect the AC power

plug when there is an electric storm.

● Since this unit has a built-in power amplifier, heat will

radiate from the rear panel. Place the unit apart from the
walls, allowing spaces of at least 20 cm above, behind
and on both sides of the unit to prevent fire or damage.
Furthermore, do not position with the rear panel facing
down on the floor or other surfaces.

● Do not cover the rear panel of this unit with a

newspaper, a tablecloth, a curtain, etc. in order not to
obstruct heat radiation. If the temperature inside the unit
rises, it may cause fire, damage to the unit and/or
personal injury.

●

Do not place small metallic objects on this unit.
Otherwise, the object may fall, possibly causing an injury.

● Do not place the following objects on this unit:

Glass, china, etc.

If glass etc. falls by vibrations and breaks, it may cause
personal injury.

A burning candle etc.

If the candle falls by vibrations, it may cause fire and
personal injury.

A vessel with water in it

If the vessel falls by vibrations and water spills, it may
cause damage to the unit, and/or you may get an
electric shock.

● Do not place this unit where foreign objects such as

water drips might fall. It might cause a fire, damage to
this unit, and/or personal injury.

● Never place a fragile object near the YST port of this

unit. If the object falls or drops by the air pressure, it may
cause damage to the unit and/or personal injury.

● Never put a hand or a foreign object into the YST port

located on the front of this unit. When moving this unit,
do not hold the port as it might cause personal injury
and/or damage to this unit.

● Never open the cabinet. It might cause an electric shock

since this unit uses a high voltage. It might also cause
personal injury and/or damage to this unit.

● When using a humidifier, be sure to avoid condensation

inside this unit by allowing enough spaces around this
unit or avoiding excess humidification. Condensation
might cause a fire, damage to this unit, and/or electric
shock.

● Super-bass frequencies reproduced by this unit may

cause a turntable to generate a howling sound. In such a
case, move this unit away from the turntable.

● This unit may be damaged if certain sounds are

continuously outputted at high volume level. For
example, if 20 Hz–50 Hz sine waves from a test disc,
bass sounds from electronic instruments, etc. are
continuously outputted, or when the stylus of a turntable
touches the surface of a disc, reduce the volume level to
prevent this unit from being damaged.

● If you hear distorted noise (i.e., unnatural, intermittent

“rapping” or “hammering” sounds) coming from this unit,
reduce the volume level. Extremely loud playing of a
movie soundtrack’s low frequency, bass-heavy sounds or
similarly loud popular music passages can damage this
speaker system.

● Vibration generated by super-bass frequencies may

distort images on a TV. In such a case, move this unit
away from the TV set.

● Do not attempt to clean this unit with chemical solvents

as this might damage the finish. Use a clean, dry cloth.

● Be sure to read the “TROUBLESHOOTING” section

regarding common operating errors before concluding
that the unit is faulty.

● Secure placement or installation is the owner’s

responsibility.
YAMAHA shall not be liable for any accident caused
by improper placement or installation of speakers.

● VOLTAGE SELECTOR

(For China, Korean and General models)
The voltage selector switch on the rear panel of this
unit must be set for your local
main voltage BEFORE plugging
this unit into the AC main supply.
Voltages are 110-120/220-240 V AC,
50/60 Hz.

Standby mode
If the POWER switch is set to the ON position and the
AUTO STANDBY switch is set to the HIGH or LOW
position, this unit turns into the standby mode when no
signal is received by this unit for 7 to 8 minutes.
In this state, this unit is designed to consume a very
small quantity of power.

This unit features a magnetically shielded design, but
there is still a chance that placing it too close to a TV set
might impair picture color. Should this happen, move this
unit away from the TV set.

110V–120V 220V–240V

VOLTAGE

SELECTOR

E-1

CONTENTS

IMPORTANT SAFETY INSTRUCTIONS

................................................................. II

UNPACKING ...........................................IV

CAUTION .................................................. 1

FEATURES ...............................................2

SPECIFICATIONS ................................... 2

PLACEMENT ............................................ 3

CONNECTIONS....................................... 4

FEATURES

● This subwoofer system employs Advanced Yamaha
Active Servo Technology which YAMAHA has developed
for reproducing higher quality super-bass sound. (Refer to
page 9 for details on Advanced Yamaha Active Servo
Technology.) This super-bass sound adds a more
realistic, theater-in-the-home effect to your stereo system.

● For the effective use of the subwoofer, the subwoofer’s
super-bass sound should be matched to the sounds of
your main speakers. You can create the best sound
quality for various listening conditions by using the HIGH
CUT control and the PHASE switch.

CONTROLS AND THEIR

FUNCTIONS ............................................ 5

AUTOMATIC POWER-SWITCHING

FUNCTION............................................... 6

ADJUSTING THE SUBWOOFER

BEFORE USE .......................................... 7

Frequency characteristics...................... 8

ADVANCED YAMAHA ACTIVE

SERVO TECHNOLOGY ........................... 9

TROUBLESHOOTING............................ 10

● The Automatic power-switching function saves you the
trouble of pressing the STANDBY/ON button to turn the
power on or turn it to the STANDBY mode.

● You can select bass effect suitable for the source by
using the B.A.S.S. button.

QD-Bass Technology

QD-Bass (Quatre Dispersion Bass) technology uses
square, pyramid-shaped reflective plates to radiate the
sound in four horizontal directions.

SPECIFICATIONS

Type ............... Advanced Yamaha Active Servo Technology

Magnetic shielding type

Driver ....................................... 16 cm (6-1/2”) cone woofer

Amplifier Output .................................................. 70 W/5Ω

Frequency Response ............................... 30 Hz to 200 Hz

Power Supply

U.S.A. and Canada models .................... AC 120V, 60 Hz

U.K. and Europe models ........................ AC 230V, 50 Hz

Australia model ....................................... AC 240V, 50 Hz

China, Korean and General models

....................................... AC 110-120/220-240V, 50/60 Hz

E-2

Power Consumption ................................................. 70 W

Standby Power Consumption ................................. 0.8 W

Dimensions (W x H x D) ..... 280 mm x 325 mm x 320 mm

(11” x 12-13/16” x 12-5/8”)

Weight ................................................ 9.2 kg (20 lbs. 4 oz.)

* Specifications are subject to change without notice due to

product improvements.

PLACEMENT

English

Å

( : subwoofer, : main speaker)

It is recommended to place the subwoofer on the outside of
either the right or the left main speaker. (See fig. Å .) The
placement shown in fig. ı is also possible, however, if the
subwoofer system is placed directly facing the wall, the
bass effect may die because the sound from it and the
sound reflected by the wall may cancel out each other. To
prevent this from happening, face the subwoofer system at
an angle as shown in fig. Å.

Note

There may be a case that you cannot obtain enough super­bass sounds from the subwoofer when listening in the
center of the room. This is because “standing waves” have
been developed between two parallel walls and they cancel
the bass sounds.
In such a case, face the subwoofer obliquely to the wall. It
also may be necessary to break up the parallel surfaces by
placing bookshelves etc. along the walls.

ı

Use the non-skid pads

Put the provided non-skid pads at the four corners on the
bottom of the subwoofer to prevent the subwoofer from
moving by vibrations etc.

SUBWOOFER SYSTEM YST-SW015

S
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N

D

B
Y/O

N

B
.A.S

.S.

H
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H C

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–

5
0

1

50Hz

V
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–
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10

■ About this manual

• This manual is printed prior to production. Design
and specifications are subject to change in part for the
reason of the improvement in operativity ability, and
others. In this case, the product has priority.

• Some of the illustrations and names of the package
contents etc. written in this manual may differ from
the actual products and the names written on the
package etc.

E-3

CONNECTIONS

Caution: Plug in the subwoofer and other audio/video components after all connections are
completed.

Connect the subwoofer to the line output (pin jack) terminal(s) of the amplifier.

● To connect with a YAMAHA DSP amplifier (or AV
receiver), connect the SUBWOOFER (or LOW PASS etc.)
terminal on the rear of the DSP amplifier (or AV receiver)
to the L/MONO INPUT terminal of the subwoofer.

● When connecting the subwoofer to the SPLIT
SUBWOOFER terminals on the rear of the DSP amplifier,
be sure to connect the L/MONO INPUT terminal to the
“L” side and the R INPUT terminal to the “R” side of the
SPLIT SUBWOOFER terminals.

Right main speaker

Amplifier

Subwoofer

/MONO

Left main speaker

Subwoofer cable
(not included)

INPUT

AUTO

PHASE

STANDBY

OFFLOW HIGH

NORMREV

110V–120V 220V–240V

VOLTAGE
SELECTOR

POWER

ON

OFF

To AC outlet

/MONO

INPUT

AUTO

STANDBY

OFF LOW HIGH

PHASE

NORM REV

Audio pin cable
(not included)

SPLIT SUBWOOFER

SUBWOOFER

(LOW PASS)

Notes

● Some amplifiers have line output terminals labeled PRE
OUT. When you connect the subwoofer to the PRE OUT
terminals of the amplifier, make sure that the amplifier
has at least two sets of PRE OUT terminals. If the
amplifier has only one set of PRE OUT terminals, do not
connect the subwoofer to the PRE OUT terminals.

E-4

● When connecting to a monaural line output terminal of
the amplifier, connect the L/MONO INPUT terminal.

CONTROLS AND THEIR FUNCTIONS

Front panel

SUBWOOFER SYSTEM YST-SW015

STANDBY/ON B.A.S.S. HIGH CUT

50–150Hz

VOLUME

0–10

SUBWOOFER SYSTEM YST-SW015

STANDBY/ON B.A.S.S. HIGH CUT

Por t

24513

Rear panel (General model)

50–150Hz

VOLUME

English

0–10

110V–120V 220V–240V

POWER

ON

OFF

6

VOLTAGE

SELECTOR

INPUT

AUTO

PHASE

/MONO

STANDBY

OFF LOW HIGH

NORM REV

110V–120V 220V–240V

POWER

ON

OFF

7

1 Power indicator

Lights up in green while the subwoofer is on.
Lights up in red while the subwoofer is set in the
standby mode by the operation of the automatic power­switching function.
Goes off when the subwoofer is set in the standby
mode.

2 STANDBY/ON button

Press this button to turn on the power when the
POWER (

7) switch is set in the ON position. (The

power indicator lights up in green.)
Press again to set the subwoofer in the standby mode.
(The power indicator goes off.)

Standby mode
The subwoofer is still using a small amount of power
in this mode.

3 B.A.S.S. (Bass Action Selector System) button

When this button is pressed in to the MUSIC position,
the bass sound in audio software is well reproduced.
By pressing the button again so that it pops out at the
MOVIE position, the bass sound in video software is
well reproduced.

MOVIE MUSIC

INPUT

/MONO

VOLTAGE
SELECTOR

AUTO

STANDBY

OFF LOW HIGH

PHASE

NORM REV

98 0

4 HIGH CUT control

Adjusts the high frequency cut off point.
Frequencies higher than the frequency selected by this
control are all cut off (and no output).
* One graduation of this control represents 10 Hz.

100 Hz

80 Hz

70 Hz

60 Hz

90 Hz

50 Hz

110 Hz

120 Hz

140 Hz

150 Hz

130 Hz

5 VOLUME control

Adjusts the volume level. Turn the control clockwise to
increase the volume, and counterclockwise to
decrease the volume.

6 VOLTAGE SELECTOR switch

(For China, Korean and General models)

If the preset setting of the switch is incorrect, set the
switch to the proper voltage range (220V-240V or
110V-120V) of your area.
Consult your dealer if you are unsure of the correct
setting.

WARNING
Be sure to unplug the subwoofer before setting the
VOLTAGE SELECTOR switch correctly.

E-5

7 POWER switch

Normally, set this switch to the ON position to use the
subwoofer. In this state, you can turn on the subwoofer
or turn the subwoofer into the standby mode by
pressing the STANDBY/ON (
to the OFF position to completely cut off the
subwoofer’s power supply from the AC line.

2) button. Set this switch

8 INPUT terminals

Used to input line level signals from the amplifier.
(Refer to “CONNECTIONS” for details.)

9 AUTO STANDBY (HIGH/LOW/OFF) switch

This switch is originally set to the OFF position. By
setting this switch to the HIGH or LOW position, the
subwoofer’s automatic power-switching function
operates as described below. If you do not need this
function, leave this switch in the OFF position.
* Make sure to change the setting of this switch only

when the subwoofer is set in the standby mode by
pressing the STANDBY/ON (

2) button.

0 PHASE switch

Normally this switch is to be set to the REV (reverse)
position. However, according to the listening condition
or your preference, there may be a case when better
sound quality is obtained by setting this switch to the
NORM (normal) position. Select the better position by
monitoring the sound.

AUTOMATIC POWER-SWITCHING FUNCTION

IIf the source being played is stopped and the input signal is
cut off for 7 to 8 minutes, the subwoofer automatically
switches to the standby mode. (When the subwoofer
switches to the standby mode by the automatic power­switching function, the power indicator lights up in red.)
When you play a source again, the power of the subwoofer
turns on automatically by sensing audio signals input to the
subwoofer.
This function operates by sensing a certain level of low
frequency input signal. Usually set the AUTO STANDBY
switch to the LOW position. However, if this function does
not operate smoothly, set the switch to the HIGH position. In
the HIGH position, the power will turn on even with a low
level of input signal. But please be aware that the subwoofer
may not switch to the standby mode when there is an
extremely low input signal.

E-6

* The power might turn on unexpectedly by sensing noise

from other appliances. If that occurs, set the AUTO

STANDBY switch to the OFF position and use the
STANDBY/ON button to switch the power between on

and in the standby mode manually.

* This function detects the low-frequency components

below 200 Hz of the input signals (i.e., the explosion in
the action movie, the sound of the bass guitar or the bass
drum, etc.).

* The minutes required to switch the subwoofer to the

standby mode might change by sensing noise from other
appliances.

This function is available only when the power of the
subwoofer is on (by pressing the STANDBY/ON button).

ADJUSTING THE SUBWOOFER BEFORE USE

Before using the subwoofer, adjust the subwoofer to obtain the optimum volume and tone balance between the subwoofer and
the main speakers by following the procedures described below.

Front panel

SUBWOOFER SYSTEM YST-SW015

STANDBY/ON B.A.S.S. HIGH CUT

50–150Hz

VOLUME

0–10

SUBWOOFER SYSTEM YST-SW015

STANDBY/ON B.A.S.S. HIGH CUT

Rear panel

INPUT

AUTO

PHASE

/MONO

STANDBY

OFFLOW HIGH

POWER

ON

OFF

NORMREV

110V–120V 220V–240V

VOLTAGE
SELECTOR

POWER

ON

OFF

INPUT

/MONO

AUTO

STANDBY

OFF LOW HIGH

50–150Hz

NORM REV

VOLUME

1, 6583

PHASE

0–10

English

3

1 Set the VOLUME control to minimum (0).
2 Turn on the power of all the other

components.

3 Make sure that the POWER switch is set to

the ON position, then press the STANDBY/
ON button to turn on the subwoofer.

* The Power indicator lights up in green.

4 Play a source containing low-frequency

components and adjust the amplifier’s
volume control to the desired listening level.

5 Adjust the HIGH CUT control to the position

where the desired response can be
obtained.

Normally, set the control to the main speaker’s rated
minimum reproducible frequency*.
* The main speaker’s rated minimum reproducible

frequency can be looked up in the speakers’ catalog
or owner’s manual.

6 Increase the volume gradually to adjust the

volume balance between the subwoofer and
the main speakers.

Normally, set the control to the level where you can
obtain a little more bass effect than when the subwoofer
is not used. If the desired response cannot be obtained,
adjust the HIGH CUT control and the VOLUME control
again.

7

7 Set the PHASE switch to the position which

gives you the better bass sound.

Normally, set the switch to the REV (reverse) position. If
the desired response cannot be obtained, set the switch
to the NORM (normal) position.

8 Select “MOVIE” or “MUSIC” according to the

played source.

MOVIE: When a movie type source is played, the low­frequency effects are enhanced to allow the listener
enjoy more powerful sound. (The sound will be thicker
and deeper.)

MUSIC: When an ordinary music source is played, the
excessive low-frequency components are cut off to
make the sound clearer. (The sound will be lighter and
reproduces the melody line more clearly.)

• Once the volume balance between the subwoofer and
the main speakers is adjusted, you can adjust the
volume of your whole sound system by using the
amplifier’s volume control.
However, if you change the main speakers to others,
you must make this adjustment again.

• For adjusting the VOLUME control, the HIGH CUT
control and the PHASE switch, refer to “Frequency
characteristics” on the next page.

E-7

Frequency characteristics

This subwoofer’s frequency characteristics

100

The figures below show the optimum adjustment of each control and the frequency characteristics when this subwoofer is
combined with a typical main speaker system.

EX. When combined with an 3.5” or 4” (8 cm or 10 cm) acoustic suspension, 2 way system main

speakers

100 dB

HIGH CUT

50–150Hz

VOLUME

0–10

PHASE–Set to the REV
(reverse) position.
B.A.S.S.–MOVIE

90

80

70

YST-SW005

YST-SW015

60

Main

50

40

20 50 100 200 500Hz

speaker’s
response

E-8

ADVANCED YAMAHA ACTIVE SERVO TECHNOLOGY

English

The theory of Yamaha Active Servo Technology has been
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 outputted
from this opening as waves of great amplitude if 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 new 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 linear with respect to signal voltage. 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, low­frequency waves with superior damping characteristics.
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 conventional Yamaha Active
Servo Technology.

Our new Active Servo Technology — Advanced Yamaha
Active Servo Technology — adopted Advanced Negative
Impedance Converter (ANIC) circuits, which allows the
conventional negative impedance converter to dynamically
vary in order to select an optimum value for speaker
impedance variation. With this new ANIC circuits, Advanced
Yamaha Active Servo Technology can provide more stable
performance and improved sound pressure compared with
the conventional Yamaha Active Servo Technology, resulting
in more natural and dynamic bass reproduction.

High-amplitude
bass sound

Air woofer
(Helmholtz resonator)

Por t

Advanced Negative­impedance Converter

Signals of low amplitude

Active Servo
Processing
Amplifier

Cabinet

Signals

E-9

TROUBLESHOOTING

Refer to the chart below when this unit does not function properly. If the problem you are experiencing is not listed below or if
the instructions given below do not help, disconnect the power cable and contact your authorized YAMAHA dealer or service
center.

Problem

Power is not supplied even
though the STANDBY/ON button
is set to the ON position.

No sound.

Sound level is too low.

The subwoofer does not turn on
automatically.

The subwoofer does not turn into
the standby mode automatically.

The subwoofer turns into the
standby mode unexpectedly.

The subwoofer turns on
unexpectedly.

Cause

The power plug is not securely
connected.

The POWER switch is set to the OFF
position.

The VOLUME control is set to 0.
Speaker cables are not connected

securely.
Speaker cables are not connected

correctly.
Setting of the PHASE switch is not

proper.
A source sound with few bass

frequencies is played.

It is influenced by standing waves.

The POWER switch is set to the OFF
position.

The STANDBY/ON button is set to the
OFF position.

The AUTO STANDBY switch is set to
the OFF position.

The level of input signal is too low.

There is an influence of noise
generated from external appliances etc.

The AUTO STANDBY switch is set to
the OFF position.

The level of input signal is too low.

There is an influence of noise
generated from external appliances etc.

What to Do

Connect it securely.

Set the POWER switch to the ON
position.

Turn the VOLUME control to the right.
Connect them securely.

Connect them correctly, that is L (left) to
L, R (right) to R, “+” to “+” and “–” to “–”.

Set the switch to the other position.

Play a source sound with bass
frequencies.
Set the HIGH CUT control to a higher
position.

Reposition the subwoofer or break up
the parallel surface by placing
bookshelves etc. along the walls.

Set the POWER switch to the ON
position.

Set the STANDBY/ON button to the ON
position.

Set the AUTO STANDBY switch to the
“HIGH” or “LOW” position.

Set the AUTO STANDBY switch to the
“HIGH” position.

Move the subwoofer further away from
such appliances and/or reposition the
connected speaker cables.
Otherwise, set the AUTO STANDBY
switch to the “OFF” position.

Set the AUTO STANDBY switch to the
“HIGH” or “LOW” position.

Set the AUTO STANDBY switch to the
“HIGH” position.

Move the subwoofer farther away from
such appliances and/or reposition the
connected speaker cables.
Otherwise, set the AUTO STANDBY
switch to the “OFF” position.

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