woofer disengaged. A properly adjusted subwoofer/satellite system should result in a
transparent transition between the satellite and subwoofer when compared to the
satellites alone.
Section 3 – Back Panel Overview
1. Input (Right/Left) — XLR line-level (Pin 1 = Ground; Pin 2 = High; Pin 3 = Low)
2. Output (Right/Left) — XLR line-level (Pin 1 = Ground; Pin 2 = High; Pin 3 = Low)
with fixed 80-Hz, High-Pass filter
3. Clip Indicator/Limiter
4. Phase Switch (0° - 180°)
5. Low-Pass Filter Control (50 Hz – 130 Hz)
6. Gain Control
7. Low Frequency Defeat (LFD)
8. IEC Power Entry Module: On/Off switch; Fuse block/Voltage selector (100-
120/VAC - 4 A 50/60 Hz; 220-240/VAC - 2 A 50/60 Hz; use only with 250-volt fuses);
IEC Power Connector.
Section 4 – System Controls and AC Power Requirements
Phase Switch (0° or 180°)
This "Phase" switch, technically, is a polarity inversion switch.
However, since its position affects the phase relation of the sub-
woofer output to the other speakers in the room, it has been
labeled phase. The proper switch position of 0 or 180 degrees
depends on a number of variables. These variables include, the
distance of the subwoofer from the listening position and moni-
tors, as well as the system's absolute polarity and the bass response of the room.
(See Section 7, Subwoofer Setup and Placement, on how to determine the correct
switch position for your monitoring system and room.)
Note: In the interest of accuracy, please note that the words "phase" and "polarity"
often are used interchangeably by many engineers. Polarity, though, technically is
the total inversion of the signal. Phase has to do with the distance and/or timing rela-
tionship between two signals, which then may be in or out of phase by varying
degrees at a given frequency. When set to 0°, a positive voltage on pin 2 of the XLR
connector will produce an outward cone movement of the woofer and a positive
pressure in the room. When set to 180°, the same voltage will produce an inward
cone movement and negative pressure in the room.
Low-Pass Filter (variable 20Hz-130Hz)
When rotated fully counterclockwise, there is a 50-Hz, 24-dB-
per octave, low-pass filter inserted before the amplifier. When
rotated fully clockwise, the low-pass filter frequency is 130 Hz.
The 12 o'clock position corresponds to 80 Hz, which matches
the output of the high-pass filters on the XLR output jack. Note
that this control does not affect the signal level or filtering of the
XLR output connectors. (See Sections 5 & 6 — Hooking Up
Your Subwoofer.)
Gain Control (-30 dB to +6 dB)
When the gain control is rotated fully counterclockwise, the input
signal is attenuated by 30 decibels from nominal sensitivity.
When rotated fully clockwise, the input signal is boosted by 6
decibels from nominal sensitivity. At unity gain, a +4 dBV signal
will drive the amplifier section to full power output. This control
does not affect the level of the XLR output connectors.
LFD™ (Low Frequency Defeat
LFD™ (Low Frequency Defeat) footswitch removes the sub
from the signal path allowing you to evaluate impact of your
subwoofer on your mix.
Auto On/OFF Switch
The Auto On/Off feature allows you to either choose
between manually powering up the speaker or selecting the
Automatic On feature. The Auto circuit detects a signal,
turns the power on allowing it to pass a signal and shuts the
power off after 20 minutes of silence.
AC Power Requirements
Make sure that the subwoofer is connected with an IEC power cable with proper
ground, and that the voltage is set to the appropriate value. In order to avoid ground
loop induced hum, the subwoofer should be powered from the same electrical circuit
as the circuit powering other monitor speakers and mixing console. All connections
should be made, all console faders and controls should be set at minimum levels
and all other equipment should be powered on before powering on your subwoofer.
NOTE: MAKE SURE THAT THE VOLTAGE INDICATOR FOUND IN THE MIDDLE-
PORTION OF THE IEC MAINS CONTROL IS SET TO THE CORRECT VOLTAGE
SETTING FOR YOUR VOLTAGE.
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