Subwoofer Mode; X-Over - Mackie DRM18S Owner's Manual

Subwoofer Mode

Subwoofer mode allows you to change
the subwoofer's polarity.
MAIN MODE
CARDIO DELAY
What does polarity mean, though? A subwoofer
works by literally pumping air as the woofer cone
moves in and out with respect to the cabinet in which
it is housed. It does so according to the low-frequency
portion of the signal it receives from the sound source.
The woofer cone is simply following the waveform
as seen in the sine wave below-left (Normal).
As the sine wave rises, the woofer cone pushes out.
Likewise, as the sine wave falls, the woofer cone
pulls into the cabinet. A musical signal is much more
complex, of course, but the same principle applies.
Movement of the woofer cone causes air pressure
changes that we perceive as sound.
SUBWOOFER MODE
NON-INVERTED
SUBWOOFER MODE
NON-INVERTED
When invert is selected, the original waveform
is simply reversed 180˚ [See above-right].
Again, the subwoofer cone follows the waveform.
However, this time the woofer cone starts by pulling
into the cabinet followed by the woofer cone pushing
out. If you have ever experimented with a subwoofer's
polarity, you may not have noticed any changes
to the sound regardless of its position, especially
if you are listening to just the subwoofer. This is normal,
as our ears perceive them both at the same time.
subwoofer is paired with a loudspeaker.
Ideally, the woofer cones of the subwoofer and full
range loudspeaker would work together by pushing
and pulling in unison. DRM18S subwoofers are
designed to be used in a broad range of applications.
The flexibility provided by the subwoofer mode
(i.e. polarity) is necessary to ensure that you are
receiving the best possible sound from your system,

X-OVER

regardless of your setup.
mode you desire – Normal or Invert – is illuminated,
then push to select it. As seen to the left, we're going
with Normal.
CONFIG
and selecting this simply returns you to the menu.
X-Over
frequency for loudspeakers.
loudspeaker is connected to the system. The crossover
point is set to 90 Hz to work in perfect harmony with
the Mackie DRM loudspeakers. This is what we hope
you choose, thank you for your support!
loudspeaker is connected to the system. Here you
can select the crossover, ranging from 40 Hz – 160 Hz.
you desire – DRM Top or Var – is illuminated, then
push to select it. If var is selected (as seen below),
the frequency is illuminated and may be changed
by rotating the speaker control knob clockwise
(raise the frequency) and counter-clockwise
(lower the frequency).
there's a third and final selection: the left-facing
arrow. Illuminating and selecting this simply returns
you to the menu.
Polarity comes into play when the DRM18S
Rotate the speaker control knob until the subwoofer
There's also a left-facing arrow. Illuminating
DRM18S subwoofers allow you to choose a crossover
MODE
MAIN
CARDIO DELAY
There are two choices:
• DRM Top – Choose this if a Mackie DRM
• Var – Choose this if a non-Mackie DRM
Rotate the speaker control knob until the crossover
In addition to the two crossover selections,
CROSSOVER
Variable
DRM
TOP
120Hz
X-OVER
CONFIG
VAR
Owner's Manual
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