10
Model 642 SB Powered Subwoofer
Care of Your Subwoofer
Dual Subwoofer Placement
When two subwoofers are used, you may wish to place them asymmetri-
cally; that is, in slightly different positions in the room (Figure 7). This
will reduce common mode room resonances that occur with symmetri-
cally positioned subwoofers. You can also try placing the subwoofers in
the same corner, if you wish. Experiments have shown this to be a viable
means of producing smooth bass response in many rooms.
Figure 7
Asymmetrical arrangement for 2 subwoofers in a home theater, for example, one
closer to a corner than the other
The Phase Invert Control
A subwoofer operating out of phase with the rest of the
system won’t provide optimum low frequency perfor-
mance. Also, the correct subwoofer phase can enhance
room acoustics. Since there is so much variation in the
industry regarding phase, a switch that will reverse the
phase of the subwoofer is provided on the amplifier
panel. Listen to a monaural musical source with strong
bass content. (For example, you can use the mono switch on an FM tuner
or preamp, or use a Y-connector on the outputs of one of your source
components to get a mono signal.)
Experiment with the position of the phase switch to get the smoothest
bass. It should be obvious which is the correct setting. In particular, there
will be a more integrated transition between the satellites and the sub-
woofer when they are properly phased.
A Word About Bass, Center Channel Modes
and System Set Up
Many surround processors and receivers feature a “Wide” and “Normal”
mode for the center channel speaker. Atlantic Technology recommends
that the center channel be operated in the “Normal” mode when using
a powered subwoofer. The center channel speaker will sound more
dynamic and the intelligibility of the system will generally be improved
when in the “Normal” mode.
With discrete digital “5.1, 6.1, or 7.1” channel systems (Dolby Digital, DTS,
etc.) many controllers provide a Bass Management option, which lets you
set the front and rear speakers in a limited bandwidth (Small) or full
range (Large) mode. When using a subwoofer with Atlantic Technology
speakers we recommend setting such a controller to the Small position
for all the speakers in the system.
Care of Your Subwoofer
The 642 SB is constructed from 3/4” Medium Density Fiberboard. MDF
is a non-resonant material ideal for speaker system enclosures. To clean
the cabinet you may use a soft cloth either dry or slightly dampened with
clean water. Be careful not to wet the cabinet or allow any water to enter
the cabinet seams. Avoid placing your speakers in direct sunlight or near
a source of heat that may, over time, damage the finish.
IMPORTANT:
Save Your Boxes! If you can do so, save the carton,
packing pieces and plastic bags that came with your subwoofer.
They will be useful in case you move or have to ship your sub-
woofer for any reason. In any case, save all packing materials until
you are certain that the system has suffered no damage in ship-
ment. If you find such damage, either visible or internal, contact
your dealer immediately for the proper return procedure.
Place subwoofers
assymmetrically in room
for smoother bass
Using the Subwoofer LowPass Control
When used with the complete System 4200,
the 642 SB Low-pass control should be set at
around 80Hz unless you are using a proces-
sor with its own built-in crossover. The goal
is to optimize the performance of the system
by ensuring that the subwoofer and satellites
produce a cohesive and well integrated sound
“picture.” The low-frequency response of the
System 4200 satellites has been optimized to
work with approximately an 80Hz crossover point.
Higher crossover frequencies pass more bass but can sound boomy
and may be more easily localized to the subwoofer. Higher crossover
frequencies may be suitable, however, when using very small satellites
that have no real low frequency performance. Settings lower than 80Hz
should be employed if you are using larger speakers that have extended
bass response. This way, the subwoofer will only reproduce the very low-
est bass frequencies that are in the range where the large main speakers
begin to roll off.
It’s generally undesirable to have the main speakers and the subwoofer
overlap too much. Larger speakers means a lower Low-pass crossover
frequency, smaller speakers means a higher Low-pass crossover fre-
quency. Consult the manufacturer’s specified low frequency response
for your main speakers to determine the appropriate Low-pass setting
on your subwoofer. In the end, however, a little time spent experimenting
will generally result in dramatically better bass response.
110-120V
220-240V
OFF
AC INPUT
50-60Hz 300W MAX
ON
FOR 110-120VAC, USE 3A L 250V FUSE
FOR 220-240VAC, USE 2A T 250V FUSE
STANDBY
LOWPASS
LOWPASS
PHASE
OUTPUT
INPUT
NORMAL
NORMAL
OFF
ON
INVERT
BYPASS
80
120
140
40
R
L/MONO
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK
DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.
AVIS: RISQUE DE CHOC ELECTRIQUE-NE PAS OUVRIR
DOUBLE INSULATION - WHEN SERVICING USE ONLY IDENTICAL REPLACEMENT PARTS
2001310
CAN/CSA STD.E60065
CERTIFIED TO
CONFORMS TO
UL STD.6500
AUTO
DESIGNED BY ATLANTIC TECHNOLOGY IN USA,
MANUFACTURED TO SPECIFICATION IN CHINA
110-120V
220-240V
OFF
AC INPUT
50-60Hz 300W MAX
ON
FOR 110-120VAC, USE 3A L 250V FUSE
FOR 220-240VAC, USE 2A T 250V FUSE
STANDBY
LOWPASS
LOWPASS
PHASE
OUTPUT
INPUT
NORMAL
NORMAL
OFF
ON
INVERT
BYPASS
80
120
140
40
R
L/MONO
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK
DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.
AVIS: RISQUE DE CHOC ELECTRIQUE-NE PAS OUVRIR
DOUBLE INSULATION - WHEN SERVICING USE ONLY IDENTICAL REPLACEMENT PARTS
2001310
CAN/CSA STD.E60065
CERTIFIED TO
CONFORMS TO
UL STD.6500
AUTO
DESIGNED BY ATLANTIC TECHNOLOGY IN USA,
MANUFACTURED TO SPECIFICATION IN CHINA
