
CONTROLS/INDICATORS
4. Level
Match the amplifier’s input sensitivity to the output
of the pre-amp source. If the source output has a
variable control, we recommend that the user spend
a moment or two determining the best balance
between the two controls. When a
balance is found between low noise, linear level
control, and sufficient level to drive the amp to the
required output, the level knob can be considered to
be the “volume control” for the subwoofer system.
5. Low Pass Frequency
This control is used to establish the highest
frequency that the subwoofer will reproduce and
has a range between 50 and 100 Hz. Experiment
with the amount of “overlap” that you will experi-
ence when all speakers are playing in the same
range. This can be helpful when integrating the
subwoofer with the rest of the system and with the
room.
6. Phase
This knob helps to compensate for differences in the
acoustical and electrical characteristics between the
subwoofer and the main system speakers. The
relative locations of speakers in the system can
cause signicant disturbances in speaker interac-
tion due to time delay issues, or the destructive
phase interferences that can occur at certain
frequencies.
7. Power Switch
This switch manually turns the unit on and off. When
switched to the on position, the unit will rst turn on
and be fully operational. After a period of 10-15
minutes without a signal the unit will go into “stand
by” mode.
8. Power LED
When the LED is illuminated green, the amp is in
“stand by” mode.
9. Input Voltage Switch
Switches the amp between 115v and 230v for use in
different countries or regions.
NOTES ABOUT HUM
While this amplier has been designed to minimize
the possibility of hum in the subwoofer system, it is
still possible that a hum may occur in rare
circumstances. Safety grounding can create a path
for small amounts of 60 Hz energy to travel through
the line-level audio system. While not
dangerous, this energy can cause difculty with the
subwoofer auto signal sensing circuit, and will
interfere with the quiet enjoyment of your system.
The rst course of action should be trying to make
sure that all of the audio components are connected
to either the same electrical outlet, or at least into
the same circuit branch. Next, cable TV systems are
notoriously the culprit, so be sure to try disconnect-
ing all coaxial feeds that are connected to the
system. If this solves the problem, install a coaxial
line isolator and reconnect the system. Worst case,
a line-level audio isolator/transformer connected to
the line-in of the subwoofer amplier can usually
solve the problem.
Cleaning the Subwoofer
All RM series subwoofers feature lightly textured,
durable paint nish. When needed, we suggest
cleaning with a damp cloth with water only. Do not
use any kind of abrasive cleaners or detergents.