Infinity Speaker BU 1 User Manual

BU1  
Powered Subwoofer  
Model BU-1  
Owners Manual  
Part # 930-7304  
®
 
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.  
Figure A  
ANTENNA  
LEAD-IN  
WIRE  
3) Heed Warnings – All warnings on the product and in the operating  
instructions should be adhered to.  
GROUND  
CLAMP  
4) Follow Instructions – All operating and use instructions should be  
followed.  
ANTENNA  
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.  
DISCHARGE UNIT  
(NEC SECTION 810-21)  
GROUNDING CONDUCTORS  
(NEC SECTION 810-21)  
ELECTRIC  
SERVICE  
EQUIPMENT  
GROUND CLAMPS  
POWER SERVICE GROUNDING  
ELECTRODE SYSTEM  
(NEC SECTION 810-21)  
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.  
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.  
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.  
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.  
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.  
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.  
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 manufacturers instructions have been adhered to.  
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.  
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.  
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.  
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.  
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.  
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.  
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.  
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.  
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.  
 
INTRODUCTION  
ABOUT THIS PRODUCT...  
The Infinity BU-1 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-1 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-1 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.  
IMPORTANT!  
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  
VOLUME CONTROL...  
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.  
IMPORTANT!  
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-1 – Owners Manual  
1
 
POSITIONING  
POSITION WITHIN  
A ROOM WILL  
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.  
STRONGLY INFLUENCE  
PERFORMANCE...  
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 subwoofers 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 subwoofers internal amplifier. Do not place pillows  
or other objects against it.  
We recommend placing the BU-1 at least 2 to 3 feet away from a television or a computers disc-  
drive 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 subwoofers 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).  
2
Powered Subwoofer BU-1 – Owners Manual  
 
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.  
BU-1 SUB  
RIGHT  
CHANNEL  
SATELLITE  
PRIMARY  
LISTENING  
AREA  
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).  
Powered Subwoofer BU-1 – Owners Manual  
3
 
IDENTIFICATION OF CONTROLS AND  
CONNECTING AC POWER  
CONTROLS...  
CONNECTING  
Refer to Figure 2 to identify the controls of your subwoofers internal amplifier:  
AC Power: on/off switch for AC power to amplifier  
High-Level Input and Output Terminal Strips  
Low-Level Input Jacks: connect to preamplifier outputs  
Volume Control: controls volume of subwoofer  
Frequency: controls upper corner roll-off point  
B
Y
EFOOURRESUBWOOFER...  
Turn off your entire audio system prior to connecting your subwoofer. Make sure the  
subwoofers 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-1 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.  
Figure 2.  
HIGH LEVEL INPUT  
+
R
L
+
LOW LEVEL  
INPUT  
VOLUME  
FREQUENCY  
CONTROL  
Hz  
80˚  
L
AUTO  
POWER  
ON OFF  
60˚  
120˚  
180˚  
POWER  
R
MIN  
50˚  
MAX  
200˚  
+
R
L
+
HIGH LEVEL OUTPUT  
WARNING:  
TO REDUCE THE RISK OF FIRE OR ELECTRIC  
SHOCK, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.  
®
CAUTION  
RISK OF ELECTRIC SHOCK  
DO NOT OPEN  
NRTL/C  
UL-1492  
WARNING: SHOCK HAZARD-DO NOT OPEN.  
AVIS: RISQUE DE CHOC ELECTRIQUE-NE PAS OUVRIR.  
MODEL BU1 HCM  
120V~60Hz 130W  
NOT SUITABLE FOR ALL IN-WALL MOUNTING  
120V ~, 60Hz  
130W  
4
Powered Subwoofer BU-1 – Owners Manual  
 
CONNECTING YOUR SUBWOOFER  
TURN OFF ALL POWER...  
There are several ways to connect your BU-1 subwoofer. Read this section carefully to  
determine which method is best suited for your installation.  
The BU-1 may be fed directly with a low-level signal taken from your preamplifiers 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) Yconnectors (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 preamplifiers left and right  
outputs and connect the other end to the corresponding left and right LOW-LEVEL INPUTS (1)  
on the subwoofer.  
IMPORTANT!  
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.  
Figure 3a. Low-level signal  
can be used from your preamp's  
output by connecting second  
set of output jacks to the  
OUTPUTS  
(Preamp with two  
sets of outputs)  
L
R
TO SATELLITE  
SPEAKER AMPLIFIER  
rear of your amplifier.  
L
R
LEFT  
HIGH LEVEL INPUT  
+
R
L
+
LOW LEVEL  
INPUT  
L
AUTO  
POWER  
ON OFF  
POWER  
R
+
R
L
+
HIGH LEVEL OUTPUT  
BU-1  
SUBWOOFER  
PLATE  
RIGHT  
Powered Subwoofer BU-1 – Owners Manual  
5
 
CONNECTING YOUR SUBWOOFER (CONTD)  
Figure 3b. You can use this method  
(2 “Yconnectors) if your preamp  
has only one set of outputs.  
OUTPUTS  
(Preamp with one  
set of outputs)  
L
R
Y” Connector  
TO SATELLITE  
SPEAKER AMPLIFIER  
HIGH LEVEL INPUT  
+
R
L
+
LEFT  
LOW LEVEL  
INPUT  
L
AUTO  
POWER  
ON OFF  
POWER  
R
+
R
L
+
HIGH LEVEL OUTPUT  
BU-1  
SUBWOOFER  
PLATE  
RIGHT  
When using a single subwoofer, you MUST use a pair of stereo low-level leads from your  
preamplifiers 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 “Yconnector at the  
subwoofers 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,  
youll also need a Male-to-Female “Yconnector to split the mono signal to the subwoofer pair  
(see Figure 4).  
Figure 4. Method when using single  
subwoofer or two subwoofers.  
SUB OUT  
OUTPUTS  
(Preamp with mono  
subwoofer output)  
(Preamp with one  
set of outputs)  
OR  
L
R
Male-to-Female  
Y” Connector  
To Left  
To Right  
HIGH LEVEL INPUT  
HIGH LEVEL INPUT  
R – – L  
+
R
L
+
+
+
LOW LEVEL  
INPUT  
LOW LEVEL  
INPUT  
LEFT  
L
L
AUTO  
POWER  
ON OFF  
AUTO  
POWER  
ON OFF  
POWER  
POWER  
R
R
+
R
L
+
+
R
L
+
HIGH LEVEL OUTPUT  
HIGH LEVEL OUTPUT  
LEFT BU-1  
SUBWOOFER  
PLATE  
RIGHT BU-1  
SUBWOOFER  
PLATE  
Female-to-Male  
Y” Connector  
RIGHT  
6
Powered Subwoofer BU-1 – Owners Manual  
 
CONNECTING YOUR SUBWOOFER (CONT D)  
The BU-1 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).  
AMPLIFIER  
OUTPUTS  
RIGHT LEFT  
Figure 5. Method when  
using single subwoofer.  
+
+
HIGH LEVEL INPUT  
R L  
+
+
LOW LEVEL  
INPUT  
VOLUME  
FREQUENCY  
CONTROL  
Hz  
80˚  
L
AUTO  
POWER POWER  
60˚  
120˚  
180˚  
ON OFF  
R
MIN  
MAX  
50˚  
200˚  
+
R
L
+
HIGH LEVEL OUTPUT  
BU-1  
SUBWOOFER  
PLATE  
Figure 6. Method when  
using two subwoofers.  
AMPLIFIER  
OUTPUTS  
RIGHT LEFT  
+
+
HIGH LEVEL INPUT  
R – L  
HIGH LEVEL INPUT  
R – L  
+
+
+
+
AUTO  
POWER POWER  
AUTO  
POWER POWER  
ON OFF  
ON OFF  
+
R
L
+
+
R
L
+
HIGH LEVEL OUTPUT  
HIGH LEVEL OUTPUT  
RIGHT BU-1  
SUBWOOFER  
PLATE  
LEFT BU-1  
SUBWOOFER  
PLATE  
Powered Subwoofer BU-1 – Owners Manual  
7
 
CONNECTING YOUR SUBWOOFER (CONT D)  
AMPLIFIER  
OUTPUTS  
RIGHT LEFT  
Figure 7. Method when connecting  
one subwoofer to satellites.  
+
+
HIGH LEVEL INPUT  
R L  
+
+
LOW LEVEL  
INPUT  
VOLUME  
FREQUENCY  
CONTROL  
Hz  
80˚  
L
AUTO  
POWER POWER  
60˚  
120˚  
180˚  
ON OFF  
R
MIN  
MAX  
50˚  
200˚  
+
R
L
+
HIGH LEVEL OUTPUT  
BU-1  
SUBWOOFER  
PLATE  
+
+
Rear View  
Rear View  
R.SATELLITE  
L.SATELLITE  
Depending on whether you are using one or two BU-1 subwoofers, connecting your satellites  
can be accomplished in one of two ways. If you are using a single BU-1 with a pair of satellites,  
connect them as shown in Figure 7.  
If you are using two BU-1 subwoofers as a stereo pair with a pair of satellites, connect them as  
shown in Figure 8.  
IMPORTANT!  
The BU-1 subwoofer does not have a built-in passive crossover which would roll off your  
satellites’ lower frequencies. However, the BU-1 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).  
AMPLIFIER  
OUTPUTS  
RIGHT LEFT  
+
+
Figure 8. Method when connecting  
two subwoofers to satellites.  
HIGH LEVEL OUTPUT  
R L  
HIGH LEVEL OUTPUT  
R L  
+
+
+
+
AUTO  
AUTO  
POWER POWER  
POWER POWER  
ON OFF  
ON OFF  
+
R
L
+
+
R
L
+
HIGH LEVEL OUTPUT  
HIGH LEVEL OUTPUT  
RIGHT BU-1  
SUBWOOFER  
PLATE  
LEFT BU-1  
SUBWOOFER  
PLATE  
+
+
Rear View  
Rear View  
R. SATELLITE  
L. SATELLITE  
8
Powered Subwoofer BU-1 – Owners Manual  
 
OPERATION  
SET CONTROLS...  
1. Set the subwoofers Volume control  
(Fig. 2) to 12 oclock.  
(Fig. 2) to 12 oclock.  
(Fig. 2) to the ON” position.  
2. Set the subwoofers Low-Frequency Rolloff control  
3. Switch the subwoofers AC Power switch  
4. Turn on your entire audio system.  
POWER  
ON...  
5. Turn the Volume control  
(Fig. 2) to its mid position. If no sound emanates from the  
subwoofer after the auto-sensing system turns it on, 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?  
6. 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. Begin  
ADJUST VOLUME...  
with the subwoofers Frequency  
(Fig. 2) and Volume  
(Fig. 2) control at the 12 oclock  
position. Adjust the subwoofers Volume control  
(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.  
FREQUENCY CONTROL...  
8. The Frequency control  
(Fig. 2) sets the high-frequency roll-off, adjustable from 50 to  
150Hz. Where this control is set 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. If you are  
pleased with the mid-bass but want 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 get a  
reduction in low bass without changing mid-bass, turn the Frequency control UP and the  
Volume control DOWN.  
ROOM PLACEMENT...  
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-1 – Owners Manual  
9
 
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 subwoofers 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 doesnt  
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.  
10 Powered Subwoofer BU-1 – Owners Manual  
 
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.  
IMPORTANT!  
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.  
IMPORTANT!  
IMPORTANT!  
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-1 – Owners Manual 11  
 
SPECIFICATIONS – BU-1  
PERFORMANCE DATA  
Frequency Response:  
45 ~ 150Hz, ±3dB  
Input Sensitivity:  
Low Level: 50mV  
High Level: 1V  
Input Impedance:  
Output:  
Low Level: 10k  
High Level: 200kΩ  
50W RMS  
DRIVE UNITS  
Driver:  
8" woofer  
Crossover Frequency:  
50 ~ 150Hz (continuously variable)  
FINISH  
Cabinet Finish:  
Ebony Pica  
DIMENSIONS  
Width:  
Height:*  
Depth:  
11-1/2" (29.2cm)  
11-1/2" (29.2cm)  
11-1/2" (29.2cm)  
* Does not include 1-1/4" (3.2cm) for feet.  
12 Powered Subwoofer BU-1 – Owners Manual  
 
Infinity continually strives to update and improve existing products, as well as create new ones.  
The specifications and construction details in this and related Infinity publications are therefore  
subject to change without notice.  
©1999 Infinity Systems, Inc., 250 Crossways Park Drive, Woodbury, NY 11797 USA  
(800) 553-3332  
Infinity is a registered trademark of Infinity Systems, Inc.  
P/N: 930-7304  
 

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