Owner’s Manual
Part # 939-8123
®
Powered Subwoofer
Model BU-2
BU
2
THIS INFINITY PRODUCT IS DESIGNED FOR 120-VOLT USE ONLY! FOR DETAILED SAFETY PRECAUTIONS,
PLEASE SEE FOLLOWING PAGE IN THIS OWNER'S MANUAL FOR “IMPORTANT SAFETY INSTRUCTIONS.”
The lightning flash with arrowhead
symbol, within an equilateral
triangle, is intended to alert the
user 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 the user
to the presence of important
operating and maintenance
(servicing) instructions in the
literature accompanying the
product.
L’éclair avec le symbole de la flèche, placé dans les limites dun triangel équilatéral est
prévu pour avertir l’utilisateur de la présence de “tension dangereuse” non isolée dans
l’enceinte du produit qui pourrait être d’une importance suffisante pour présenter un
resque d’électrocution aux personnes.
Le point d’exclamation dans un triangel équilateral est prévu pour avertir l’utilisateur
de la présence d’instructions importantes pour les opérations et l’entretien (service)
dans les manuels fournis avec l’appareli.
ATTENTION: POUR EVITER LES CHOCS ELECTRIQUES, INTRODUIRE
LA LAME LA PLUS LARGE DE LA FICHE DANS LA BORNE
CORRESPONDANTE DE LA PRISE ET POUSSER JUSQUAU FOND.
!
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
WARNING: SHOCK HAZARD – DO NOT OPEN.
AVIS: RISQUE DE CHOC ELECTRIQUE – NE PAS OUVRIR.
CUIDADO: PELIGRO DE CHOQUE ELECTRICO – NO ABRIR.
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK
DO NOT REMOVE COVER (0R BACK)
NO USER SERVICEABLE PARTS INSIDE
REFER SERVICING TO QUALIFIED PERSONNEL
Este destello luminoso con un símbolo de punta de flecha dentro de un triángulo
equilátero tiene el objectivo de alertar al usuario sobre la presencia de “voltaje
peligroso” no aislado dentro de la caja del producto que puede ser de magnitud lo
suficientemente grande para constituir un riesgo de choque eléctrico para las personas.
Este punto de exclamación dentro de un triángulo equilátero tiene el objectivo de
alertar al usuario sobre la existencia de instrucciones operativas y de mantenimiento
(servicio) importantes en la literatura que acomaña el aparato.
CUIDADO: PARA REDUCIR EL RIESGO DE CHOQUE ELÉCTRICO, NO
RETIRE LA CUBIERTA (O RESPALDO). DENTRO NO HAY PIEZAS A
LAS QUE EL USUARIO PUEDA DAR SERVICIO. REMITA EL SERVICIO
AL PERSONAL DE SERVICIO CALIFICADO.
!
IMPORTANT SAFETY INSTRUCTIONS
1) Read Instructions – All the safety and operating instructions should be
read before the product is operated.
2) Retain Instructions – The safety and operating instructions should be
retained for future reference.
3) Heed Warnings – All warnings on the product and in the operating
instructions should be adhered to.
4) Follow Instructions – All operating and use instructions should be
followed.
5) Cleaning – Unplug this product from the wall outlet before cleaning. Do
not use liquid cleaners or aerosol cleaners. Use a damp cloth for cleaning.
Exception: A product that is meant for uninterrupted service and that for
some specific reason, such as the possibility of the loss of an authorization
code for a CATV Converter, is not intended to be unplugged by the user for
cleaning or any other purpose, may exclude the reference to unplugging the
product in the cleaning description otherwise required in number 5.
6) Attachments – Do not use attachments not recommended by the product
manufacturer as they may cause hazards.
7) Water and Moisture – Do not use this product near water – for example,
near a bathtub, washbowl, kitchen sink, or laundry tub; in a wet basement;
or near a swimming pool; and the like.
8) Accessories – Do not place this product on an unstable cart, stand, tripod,
bracket, or table. The product may fall, causing serious
injury to a child or adult, and serious damage to the
product. Use only with a cart, stand, tripod,
bracket, or table recommended by the
manufacturer, or sold with the product. Any
mounting of the product should follow the
manufacturer’s instructions, and should use a
mounting accessory recommended by the
manufacturer.
9) A product and cart combination should be
moved with care. Quick stop, excessive force, and
uneven surfaces may cause the product and cart
combination to overturn.
10) Ventilation – Slots and openings in the cabinet are provided for
ventilation and to ensure reliable operation of the product and to protect it
from overheating, and these openings must not be blocked or covered. The
openings should never be blocked by placing the product on a bed, sofa, rug,
or other similar surface. This product should not be placed in a built-in
installation such as a bookcase or rack unless proper ventilation is provided or
the manufacturer’s instructions have been adhered to.
11) Power Sources – This product should be operated only from the type of
power source indicated on the marking label. If you are not sure of the type
of power supply to your home, consult your product dealer or local power
company. For products intended to operate from battery power, or other
sources, refer to the operating instructions.
12) Grounding or Polarization – This product may be equipped with a
polarized alternating-current line plug (a plug having one blade wider than
the other). This plug will fit into the power outlet only one way. This is a
safety feature. If you are unable to insert the plug fully into the outlet, try
reversing the plug. If the plug should still fail to fit, contact your electrician to
replace your obsolete outlet. Do not defeat the safety purpose of the polarized
plug.
13) Power-Cord Protection – Power-supply cords should be routed so that
they are not likely to be walked on or pinched by items placed upon or
against them, paying particular attention to cords at plugs, convenience
receptacles, and the point where they exit from the product.
14) Outdoor Antenna Grounding – If an outside antenna or cable system is
connected to the product, be sure the antenna or cable system is grounded so
as to provide some protection against voltage surges and built-up static
charges. Article 810 of the National Electrical Code, ANSI/NFPA 70,
provides information with regard to proper grounding of the mast and
supporting structure, grounding of the lead-in wire to an antenna discharge
unit, size for grounding conductors, location of antenna-discharge unit,
connection to grounding electrodes, and requirements for the grounding
electrode. See Figure A.
15) Lightning – For added protection for this product during a lightning
storm, or when it is left unattended and unused for long periods of time,
unplug it from the wall outlet and disconnect the antenna or cable system.
This will prevent damage to the product due to lightning and power-line
surges.
16) Power Lines – An outside antenna system should not be located in the
vicinity of overhead power lines or other electric light or power circuits, or
where it can fall into such power lines or circuits. When installing an outside
antenna system, extreme care should be taken to keep from touching such
power lines or circuits as contact with them might be fatal.
17) Overloading – Do not overload wall outlets, extension cords, or integral
convenience receptacles as this can result in a risk of fire or electric shock.
18) Object and Liquid Entry – Never push objects of any kind into this
product through openings as they may touch dangerous voltage points or
short-out parts that could result in a fire or electric shock. Never spill liquid
of any kind on the product.
19) Servicing – Do not attempt to service this product yourself as opening or
removing covers may expose you to dangerous voltage or other hazards. Refer
all servicing to qualified service personnel.
20) Damage Requiring Service – Unplug this product from the wall outlet
and refer servicing to qualified service personnel under the following
conditions:
a) When the power-supply cord or plug is damaged.
b) If liquid has been spilled, or objects have fallen into the product.
c) If the product has been exposed to rain or water.
d) If the product does not operate normally by following the operating
instructions. Adjust only those controls that are covered by the operating
instructions as an improper adjustment of other controls may result in
damage and will often require extensive work by a qualified technician to
restore the product to its normal operation.
e) If the product has been dropped or damaged in any way.
f) When the product exhibits a distinct change in performance – this
indicates a need for service.
21) Replacement Parts – When replacement parts are required, be sure the
service technician has used replacement parts specified by the manufacturer or
that have the same characteristics as the original part. Unauthorized
substitutions may result in fire, electric shock, or other hazards.
22) Safety Check – Upon completion of any service or repairs to this
product, ask the service technician to perform safety checks to determine that
the product is in proper operating condition.
23) Wall or Ceiling Mounting – The product should be mounted to a wall
or ceiling only as recommended by the manufacturer.
24) Heat – The product should be situated away from heat sources such as
radiators, heat registers, stoves, or other products (including amplifiers) that
produce heat.
ANTENNA
LEAD-IN
WIRE
GROUND
CLAMP
ELECTRIC
SERVICE
EQUIPMENT
ANTENNA
DISCHARGE UNIT
(NEC SECTION 810-21)
GROUNDING CONDUCTORS
(NEC SECTION 810-21)
GROUND CLAMPS
POWER SERVICE GROUNDING
ELECTRODE SYSTEM
(NEC SECTION 810-21)
Figure A
1 ◆Powered Subwoofer BU-2 – Owner’s Manual
A
BOUTTHISPRODUCT
...
I
MPORTANT
!
V
OLUMECONTROL
...
I
MPORTANT
!
INTRODUCTION
The Infinity BU-2 Powered Subwoofer has been designed to enhance the bass frequencies of any
audio system. This subwoofer may be used with speakers of any size. Obviously, the greatest bass
enhancement will be achieved when the subwoofer is connected with speakers that do not have
the capability to create deep bass. This subwoofer may be used individually, or combined with
another BU-2 for even more impressive reproduction of bass frequencies (i.e., one subwoofer
near the satellite speakers and a second subwoofer behind the primary listening area, or both
subwoofers up front).
The BU-2 is a self-powered system utilizing a solid-state, low-frequency monophonic amplifier
driving a specially designed woofer mounted within a structurally rigid, tuned port enclosure.
UNPACKING THE SUBWOOFER
Check your subwoofer carefully. If it has been damaged in transit, report the damage
immediately by calling your dealer and/or the trucking firm that delivered it.
To prevent fire or shock hazard, DO NOT EXPOSE THIS SUBWOOFER SYSTEM TO RAIN
OR EXCESSIVE MOISTURE. To avoid electric shock, DO NOT OPEN THE SUBWOOFER!
There are no user serviceable parts inside. Observe all warnings and cautions.
A FEW SUGGESTIONS
We recommend that you not operate your speakers or subwoofer with the bass, treble and
loudness controls set to full boost. This will place undue strain on your electronics and speakers
and could damage them.
The volume control setting on your preamplifier or stereo receiver is not a specific indication of
the overall loudness level of the speakers. The only important consideration is the loudness
level at which the system can be played regardless of where the volume control is set.
Always turn down the volume control setting on your preamplifier or stereo when changing a
cassette or CD, or switching inputs to AM or FM operation. Excessively loud transients (clicks
or popping sounds) can damage the satellite speakers and possibly the subwoofer.
Whenever changing cables, pulling plugs, etc., ALWAYS TURN OFF ALL EQUIPMENT,
including the subwoofer. This prevents transients from entering the speakers and prevents
electrical energy from reaching you. Keep all connections out of the reach of children.
Powered Subwoofer BU-2 – Owner’s Manual ◆2
P
OSITIONWITHIN
A R
OOMWILL
S
TRONGLYINFLUENCE
P
ERFORMANCE
...
POSITIONING
Since the installation of a subwoofer is somewhat more complicated than installing full-range
speakers, it is essential you read this section very carefully prior to connecting the subwoofer to
your system. Should you have questions relating to your installation, it is advisable to call either
your dealer or Infinity’s Customer Service Department for advice.
The performance of the subwoofer is directly related to its placement in the listening room and
how you align the subwoofer with its satellite speakers. Setting the volume of the subwoofer in
relationship to the left and right speakers is also of critical importance because it is essential that
the subwoofer integrates smoothly with the entire system. Setting the subwoofer’s volume level
too high will result in an overpowering, boomy bass. Setting the volume level too low will
negate the effect of the subwoofer.
The metal plate acts as the heat sink for the subwoofer’s internal amplifier. Do not place pillows
or other objects against it.
We recommend placing the BU-2 at least 2 to 3 feet away from a television or a computer’s discdrive system to prevent smearing the colors of the TV picture or erasing of the magnetic drive.
Here are several additional facts on installation that may prove useful. It is generally believed by
most audio authorities that low frequencies (below 125Hz) are nondirectional and, therefore,
placement of a subwoofer within any listening room is not critical. While in theory it is true that
the larger wavelengths of extremely low frequencies are basically non-directional, the fact is that
when installing a subwoofer within the limited confines of a room, reflections, standing waves
and absorptions generated within the room will strongly influence the performance of any
subwoofer system. As a result, specific location of the subwoofer becomes important, and we
strongly recommend that you experiment with placement before choosing a final location.
Placement will depend upon your room and the amount and quality of bass required (for
example, whether or not your room permits placement of the subwoofer near either satellite).
Never place the port too close to a wall or piece of furniture as this will prevent the port from
operating properly. Since the port is an integral part of the subwoofer’s design, it should always
be permitted free access to the listening room without obstruction to the pressure emerging
from it. Careful experimentation will enable you to determine the best position for the
subwoofer (see useful hints, next page).
Figure 1. This view shows the
subwoofer positioned behind the
right-channel satellite speaker to
re-create the actual location of
bass instruments in an orchestra.
Here are some useful hints:
1. Experimentation with the port direction may be useful. At times directing the port away
from the listening area (to the side) may be advantageous because this may create a better
blend of bass within the listening room.
2. If bass response seems inadequate, move it closer to a wall or corner. If bass becomes too
heavy, try turning the subwoofer with the port facing away from the wall. This will tend to
diminish bass output.
It will take time and patience to find the most pleasing acoustic location for your subwoofer.
Testing for sonic balance and blending should always be made for your normal listening
position, using a wide range of source material. As a starting point, initially place the subwoofer
behind your right-channel satellite speaker, about 3 or 4 inches from the wall. We suggest
trying this location first because in an orchestra, the bass instruments are usually located in the
back and to the right (see Figure 1).
3 ◆Powered Subwoofer BU-2 – Owner’s Manual
BU-2 SUB
RIGHT
CHANNEL
SATELLITE
PRIMARY
LISTENING
AREA
Powered Subwoofer BU-2 – Owner’s Manual ◆4
C
ONTROLS
...
B
EFORECONNECTING
Y
OURSUBWOOFER
...
Figure 2.
IDENTIFICATION OF CONTROLS AND
CONNECTING AC POWER
Refer to Figure 2 to identify the controls of your subwoofer’s internal amplifier:
❶
Auto Power: on/off switch for auto-sensing of audio signal
❷
High Level Input and Output terminal strips
❸
Low Level Input jacks: connect to preamplifier outputs
❹
Volume Control: controls volume of subwoofer
❺
Phase: reverse/normal switch to flip audio signal polarity
❻
Frequency: controls upper corner roll-off point
❼
AC Power: on/off switch for AC power to amplifier
Turn off your entire audio system prior to connecting your subwoofer. Make sure the
subwoofer’s ON/OFF switch is in the “OFF” position.
If using an unswitched AC outlet on your receiver or amplifier is not possible, connect your
subwoofer to an unswitched AC wall outlet. The BU-2 includes an “Auto-Sensing” circuit that
automatically turns the subwoofer on when detecting music or voice signals. The absence of an
audio signal for approximately six minutes will cause the auto-sensing circuit to shut down
the system.
®
NRTL/C
UL-1492
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
WARNING: SHOCK HAZARD – DO NOT OPEN.
AVIS: RISQUE DE CHOC ELECTRIQUE – NE PAS OUVRIR.
CUIDADO: PELIGRO DE CHOQUE ELECTRICO – NO ABRIR.
WARNING:
TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE
NOT SUITABLE FOR ALL IN-WALL MOUNTING
MODEL BU2
120V~60Hz 230W
HCM
HIGH LEVEL INPUT
+R –L +
HIGH LEVEL OUTPUT
–
+R –L +–
LOW LEVEL
INPUT
L
R
VOLUME
CONTROL
MIN
MAX
FREQUENCY
Hz
180˚
120˚
80˚
60˚
200˚
50˚
120V ~, 60Hz
230W
POWER
AUTO
POWER
ON OFF
PHASE
-180˚ 0˚
❹❸❷❶
❺
❻
❼
5 ◆Powered Subwoofer BU-2 – Owner’s Manual
CONNECTING YOUR SUBWOOFER
There are several ways to connect your BU-2 subwoofer. Read this section carefully to
determine which method is best suited for your installation.
The BU-2 may be fed directly with a low-level signal taken from your preamplifier’s output by
using the second set of output jacks on the rear of your preamplifier (see Figure 3a). If your
preamplifier has only one set of outputs you may use two (2) “Y” connectors (see Figure 3b) to
connect your subwoofer. Use standard shielded leads terminated at each end with male RCA
connectors. Connect one end of each stereo pair of leads to your preamplifier’s left and right
outputs and connect the other end to the corresponding left and right LOW-LEVEL INPUTS (1)
on the subwoofer.
If you are using a tube preamplifier and the connecting leads will be longer than 10 feet
(3 meters), we recommend not using the above connection method. A tube preamplifier may
not be able to handle the capacitance introduced by leads over 10 feet in length. Instead, try
using the high-level connection methods listed on page 7.
T
URNOFFALLPOWER
...
I
MPORTANT
!
Figure 3a. Low-level signal
can be used from your preamp's
output by connecting second
set of output jacks to the
rear of your amplifier.
BU-2
SUBWOOFER
PLATE
LEFT
RIGHT
L
L
R
R
OUTPUTS
TO SATELLITE
SPEAKER AMPLIFIER
(Preamp with two
sets of outputs)
POWER
AUTO
POWER
ON OFF
HIGH LEVEL INPUT
+R –L +
HIGH LEVEL OUTPUT
–
+R –L +–
LOW LEVEL
INPUT
L
R
Figure 3b. You can use this method
(2 “Y”connectors) if your preamp
has only one set of outputs.
Figure 4. Method when using single
subwoofer or two subwoofers.
CONNECTING YOUR SUBWOOFER (CONT’D)
When using a single subwoofer, you MUST use a pair of stereo low-level leads from your
preamplifier’s outputs. When using two subwoofers, one for the left and another for the right
channel, connect the left preamplifier output to BOTH the left and right LOW-LEVEL INPUTS
of the subwoofer used for the left channel by using a Female-to-Male “Y” connector at the
subwoofer’s input and the right channel preamplifier output to both jacks of the right channel
subwoofer in the same manner (see Figure 4). If the preamplifier has a mono subwoofer output,
you’ll also need a Male-to-Female “Y” connector to split the mono signal to the subwoofer pair
(see Figure 4).
Powered Subwoofer BU-2 – Owner’s Manual ◆6
LEFT BU-2
SUBWOOFER
PLATE
RIGHT BU-2
SUBWOOFER
PLATE
LEFT
RIGHT
LR
OUTPUTS
(Preamp with one
set of outputs)
SUB OUT
OR
To Left
To Right
(Preamp with mono
subwoofer output)
Female-to-Male
“Y” Connector
Male-to-Female
“Y” Connector
POWER
AUTO
POWER
ON OFF
HIGH LEVEL INPUT
+R –L+
HIGH LEVEL OUTPUT
–
+R –L+–
LOW LEVEL
INPUT
L
R
POWER
AUTO
POWER
ON OFF
HIGH LEVEL INPUT
+R –L+
HIGH LEVEL OUTPUT
–
+R –L+–
LOW LEVEL
INPUT
L
R
OUTPUTS
LR
(Preamp with one
set of outputs)
“Y” Connector
TO SATELLITE
SPEAKER AMPLIFIER
HIGH LEVEL INPUT
+R –L+
LEFT
POWER
AUTO
POWER
ON OFF
–
+R –L+–
HIGH LEVEL OUTPUT
LOW LEVEL
INPUT
L
R
BU-2
SUBWOOFER
PLATE
RIGHT
7 ◆Powered Subwoofer BU-2 – Owner’s Manual
Figure 5. Method when
using single subwoofer.
Figure 6. Method when
using two subwoofers.
CONNECTING YOUR SUBWOOFER (CONT’D)
The BU-2 subwoofer may be connected to your system using the HIGH-LEVEL INPUTS (4) on
the plate located on the rear panel of the subwoofer. Use ordinary lamp cord maintaining
proper polarity (+ to + and – to –). Attach the lamp cord to the left and right HIGH-LEVEL
INPUTS on the subwoofer and the other ends to the proper left and right OUTPUTS on your
amplifier or receiver (see Figure 5).
If you plan to use two subwoofers (one for the left and the other for the right channel) connect
wires from the left and right OUTPUT on your power amplifier or receiver and attach the other
ends to the corresponding HIGH-LEVEL INPUTS on each subwoofer. Observe polarity
(see Figure 6).
POWER
AUTO
POWER
ON OFF
+R –L +
HIGH LEVEL OUTPUT
–
+R –L +–
LOW LEVEL
INPUT
L
R
VOLUME
CONTROL
MIN
MAX
FREQUENCY
Hz
180˚
120˚
80˚
60˚
200˚
50˚
HIGH LEVEL INPUT
AMPLIFIER
OUTPUTS
+
––
+
LEFTRIGHT
BU-2
SUBWOOFER
PLATE
PHASE
-180˚ 0˚
RIGHT BU-2
SUBWOOFER
PLATE
LEFT BU-2
SUBWOOFER
PLATE
POWER
AUTO
POWER
ON OFF
R–L+
HIGH LEVEL OUTPUT
+R –L +–
POWER
AUTO
POWER
ON OFF
+R L +
HIGH LEVEL OUTPUT
–
+R –L +–
HIGH LEVEL INPUT
–+
HIGH LEVEL INPUT
–
AMPLIFIER
OUTPUTS
+
––
+
LEFTRIGHT
Figure 7. Method when connecting
one subwoofer to satellites.
I
MPORTANT
!
Figure 8. Method when connecting
two subwoofers to satellites.
CONNECTING YOUR SUBWOOFER (CONT’D)
Depending on whether you are using one or two BU-2 subwoofers, connecting your satellites
can be accomplished in one of two ways. If you are using a single BU-2 with a pair of satellites,
connect them as shown in Figure 7.
If you are using two BU-2 subwoofers as a stereo pair with a pair of satellites, connect them as
shown in Figure 8.
The BU-2 subwoofer does not have a built-in passive crossover which would roll off your
satellites’ lower frequencies. However, the BU-2 does have a variable frequency control that
can be used to block unwanted frequencies (between 50 – 150Hz) from being reproduced by
the subwoofer. Where you set this control depends on the low-frequency capabilities of your
satellite speakers. Adjust this knob to the lowest frequency that your satellite speakers were
designed to reproduce (refer to Operation, step 8).
Powered Subwoofer BU-2 – Owner’s Manual ◆8
AMPLIFIER
OUTPUTS
LEFTRIGHT
+
+
––
HIGH LEVEL INPUT
+R –L +
AUTO
POWER
POWER
ON OFF
BU-2
SUBWOOFER
PLATE
–
+R –L +–
HIGH LEVEL OUTPUT
LOW LEVEL
INPUT
VOLUME
CONTROL
L
R
MIN
FREQUENCY
Hz
80˚
120˚
60˚
PHASE
-180˚ 0˚
MAX
180˚
50˚
200˚
+
–
Rear View
R. SATELLITE
+
–
Rear View
L. SATELLITE
AMPLIFIER
OUTPUTS
LEFTRIGHT
+
+
––
AUTO
POWER
POWER
ON OFF
RIGHT BU-2
SUBWOOFER
PLATE
R. SATELLITE
HIGH LEVEL OUTPUT
+R –L +
–
+R –L +–
HIGH LEVEL OUTPUT
+
–
Rear View
HIGH LEVEL OUTPUT
+R –L +
–
AUTO
POWER
POWER
ON OFF
+R –L +–
HIGH LEVEL OUTPUT
LEFT BU-2
SUBWOOFER
PLATE
+
–
Rear View
L. SATELLITE
9 ◆Powered Subwoofer BU-2 – Owner’s Manual
SETC
ONTROLS
...
P
OWERON
...
A
DJUSTVOLUME
...
F
REQUENCYCONTROL
...
R
OOMPLACEMENT
...
OPERATION
1. Initially set the BU-2’s Volume control ❹(Fig. 2) to 12 o’clock.
2. Initially set the BU-2’s Frequency control
❻
(Fig. 2) to 12 o’clock.
3. Slide the BU-2’s Phase switch
❺
(Fig. 2) to the “NOM” position (for normal polarity).
4. (Optional) Slide the BU-2’s Auto Power switch
❶
(Fig. 2) to the “ON” position (otherwise
“OFF” defeats auto-sensing).
5. Turn on your entire audio system.
6. Turn the Volume control
❹
(Fig. 2) to its mid position. If no sound emanates from the
subwoofer after the auto-sensing system turns it on (i.e., LED goes from red to green),
check the AC line cord and input cables. Are the connectors on the cables making proper
contact? Is the AC plug connected to a “live” receptacle? Once you have confirmed that the
subwoofer is active, proceed by playing a CD, record, or cassette. Use a selection that has
ample bass information.
7. Set the overall volume control of the preamplifier or stereo to a comfortable level. Adjust the
subwoofer’s Volume control
❹
(Fig. 2) until you obtain a pleasing blend of bass. Bass
response should not overpower the room but rather be adjusted so there is a harmonious
blend across the entire musical range. Many users have a tendency to set the subwoofer
volume too loud following the belief that a subwoofer is there to produce lots of bass. This
is not entirely true. A subwoofer is there to enhance bass, extending the response of the
entire system so the bass can be felt as well as heard. However, overall balance must be
maintained; otherwise, the music will not sound natural. An experienced listener will set
the volume of the subwoofer so its impact on bass response is always there but is never
obtrusive.
8. The Frequency control
❻
(Fig. 2) sets the high frequency roll-off, adjustable from 50 to
200Hz. Where you set this control depends on the low frequency capabilities of your
satellite speakers, system placement, and other factors affecting the mid-bass region. Turn
the control UP (clockwise) until you feel there is too much mid-bass information (around
100Hz) then back the control down a bit until that area sounds more natural. To hear more
low bass, turn the Frequency Control DOWN a bit and the Volume control UP by about the
same amount. This will increase low bass while leaving the mid-bass sounding the same as
it did before the adjustment. To reduce low bass without changing mid-bass, turn the
Frequency control UP and the Volume control DOWN. Alternately slide the Phase switch
between “NOM’ and “REV” positions while listening to music. The selection that sounds the
best is the correct adjustment for your system.
9. Room placement of the subwoofer is the most critical aspect of its installation. It will be
necessary for you to try various locations in your listening room before you choose the final
location. Some possible starting points include: behind the right channel satellite speaker,
along the back wall between the satellites, along a side wall (but not too close to a corner),
or behind a couch or a chair.
In general, the closer the subwoofer is to walls and corners, the greater the effect of low
frequency enhancement. Experiment with the Frequency and Volume Controls in different
locations until you are pleased with the result you obtain from your particular application.
Powered Subwoofer BU-2 – Owner’s Manual ◆10
A WORD OF ADVICE
The Low-Frequency Rolloff and Volume controls may be set anywhere within their rotation.
However, it will be a most unusual circumstance if you have to set the Volume control
completely clockwise. This may indicate an unbalanced condition in your system (too much
bass) or an especially large room or room placement may not be correct. Try several other
locations before concluding that the Volume control must be set at maximum.
In the event that the subwoofer is located so far from the listening area that its effect is not as
prominent as desired, you may find that reversing the phase of the High-Level Input wires may
help. Connect the “+” speaker output terminals to the “–” High-Level Input terminals of the
subwoofer on BOTH channels. (Reversing the phase on only one channel will cancel out the
signal to the subwoofer’s amplifier, resulting in less output from the subwoofer.)
OVERDRIVE PROTECTION
Automatic limiting circuitry helps prevent overdriving a connected subwoofer by softly clipping
the input signal if it exceeds a predetermined threshold. Depending on the level, you may or
may not hear slight distortion on musical peaks. This protection is completely automatic, with
no user adjustments. However, if you do hear distortion continuously while playing music, the
input signal level (feeding the BU-1) may be too high and should be lowered. If this doesn’t
solve the problem, verify the connections and check for proper operation of other components
in the audio chain.
A WORD ABOUT TONE CONTROLS
The tone controls on your electronic components (preamplifier, receiver, etc.) should be used
with the utmost discretion. Excessive boost can create severe power demands on your power
amplifier. Maximum bass boost can create a demand for literally hundreds of watts in the bass
region, whereas, in the “flat” position, or with the tone controls switched out of the system,
your average listening level may be impressively and realistically loud at less than 10 watts. The
remaining power capacity required is on reserve for power peaks on sharp transients and
powerful crescendos.
11 ◆Powered Subwoofer BU-2 – Owner’s Manual
I
MPORTANT
!
I
MPORTANT
!
I
MPORTANT
!
CARE OF YOUR SUBWOOFER
Your Infinity subwoofer cabinet is finished with a heavy-duty, high-quality vinyl which requires
very little maintenance. Keep the cabinet clean by dusting it occasionally with a damp cloth or
use a good quality furniture polish to maintain its original luster. (When using aerosol products,
always spray the cloth, not the speaker, to prevent any of the product from drifting onto the
electronics of the unit.)
FEEDBACK
If the bass seems boomy, or you notice a rumbling sound when listening to record albums, the
cause may be acoustic feedback. This means that low-frequency vibrations from your speakers
are reaching the turntable. To help isolate the turntable from these vibrations, place the
turntable on a heavy, solid support, as far away as possible from the subwoofer. If you continue
to experience difficulties after experimenting with placement, consult your Infinity dealer.
CD players are also susceptible to acoustic feedback and should be placed on solid supports to
isolate them acoustically. Another method to isolate the CD player is to place it on four
isolation feet available at your local dealer.
IN CASE OF TROUBLE WITH
YOUR SUBWOOFER
If the subwoofer sound is distorted, stops playing or otherwise seems to be malfunctioning, first
determine if the problem is in the subwoofer or the wiring and/or other audio components. If
the problem also affects the satellite speakers, the cause is most likely in your electronics. If it is
only noticed in the subwoofer, make sure that all connecting cables are correct and in proper
working condition. Make sure the subwoofer is plugged in and turned on.
If everything seems to be in good working order and the subwoofer still malfunctions,
DO NOT ATTEMPT ANY REPAIRS! Contact your Infinity dealer and get the name of the
authorized Infinity service center near you. If there is no facility near you, contact Infinity's
Customer Service Department at (800)553-3332, or write:
Infinity Systems, Inc. – CUSTOMER SERVICE
250 Crossways Park Drive, Woodbury, NY 11797 USA
Do not ship your subwoofer for service without prior approval (RETURN AUTHORIZATION),
and do not ship without enclosing a copy of your original bill of sale.
Powered Subwoofer BU-2 – Owner’s Manual ◆12
P
ERFORMANCEDATA
D
RIVEUNITS
F
INISH
D
IMENSIONS
SPECIFICATIONS – BU-2
Frequency Response: 30 ~ 150Hz, ±3dB
Input Sensitivity: Low Level: 70mV
High Level: 1.7V
Input Impedance: Low Level: 12k
Ω
High Level: 5kΩ
Output: 100Wrms
Driver: 12" woofer
Crossover Frequency: 50 ~ 200Hz (continuously variable)
Cabinet Finish: Ebony Pica
Width: 14-1/2" (36.8cm)
Height:* 14-1/2" (36.8cm)
Depth: 14-1/2" (36.8cm)
* Does not include 1-3/4" (4.5cm) for feet.
P/N: 939-8123
®
Infinity Systems, Inc.
250 Crossways Park Drive
Woodbury, NY 11797 USA
(516) 496-3400 • FAX (516) 682-3526
www.infinitysystems.com
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