Stereo/Mono Switch [Full Range]; High Pass Mode; Power Led Switch - Mackie SRM1550 Owner's Manual

SRM1550 Subwoofer: Rear Panel Features continued...
9
They are wired as follows, according to standards
specified by the AES (Audio Engineering Society):
Balanced XLR Output Connector
Pin 1 – Shield (ground)
Pin 2 – Positive (+ or hot)
Pin 3 – Negative (– or cold)
Balanced XLR Output Connector
See page 7 to learn more about daisy-chaining
SRM1550 subwoofers.

8. Stereo/Mono Switch [Full Range]

This switch allows you to choose whether the
A and B inputs are sent out separately [switch out]
or as a mono sum of both inputs [switch in] via the
full range outputs.
This is useful and saves the hassle of additional
cable runs when connecting multiple (mono)
subwoofers. Instead of running two cables from
the first subwoofer to the next one, simply engage
the switch and the signals from both inputs are
combined on either full range output.
10
SRM1550 Powered Subwoofer
10
8
SHIELD 1
3
2
COLD
HOT
SHIELD
1
3 COLD
2
HOT

9. High Pass Mode

The high pass mode allows you to optimize
the subwoofer and SRM loudspeakers connected
to the SRM1550's high pass outputs. If not using
SRM350 or SRM450 loudspeakers, a variable mode
allows you to select the best high pass mode suited
for your PA system from 60 Hz to 120 Hz.
Frequencies below the crossover frequency are sent
to the subwoofer. Additionally, the SRM loudspeaker
presets apply alignment delay to the subwoofer creating
an optimally aligned 3-way system. Frequencies above
the selected crossover frequency are sent to the high
pass outputs [6]. The high pass mode should be set
to the lowest frequency response rating of the main
loudspeakers. Press the high pass mode button
repeatedly until the desired high pass mode setting
LED illuminates. If "variable" is selected, turn the high
pass mode knob to the frequency you desire.
SRM350 – 115 Hz plus alignment delay
SRM450 – 110 Hz plus alignment delay
VAR – 60 Hz – 120 Hz

10. Power LED Switch

The power LED on the front of the SRM1550
illuminates when this switch is disengaged and
AC power is available at the mains input [1].
Engage the switch if you do not want the power
LED to illuminate.
Congratulations, you have reached the end of
the features section! At this point, you should have
a pretty good understanding of how the SRM1550
subwoofer functions. The following pages discuss
SRM1550 placement, an in-depth look at polarity
and Smart Protect, technical information and more.
Check it out!