DLM12S P
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DLM12S Powered Subwoofer
Placement
The DLM12S subwoofer is designed to sit on the
floor or stage. It is not designed to be pole-mounted
or suspended.
When pole-mounting loudspeakers, be sure that the
DLM12S subwoofers are stabilized and secured from
falling over or being accidentally pushed over. For
stacked scenarios, it is highly suggested that straps are
utilized. Failure to follow these precautions may result
in damage to the equipment, personal injury, or death.
The cabinet has no rigging points and is
not suitable for rigging. NEVER attempt to
suspend a DLM12S subwoofer by its handles.
As with any powered components, protect them from
moisture and extreme cold and follow the other Care
and Maintenance suggestions below.
The Ins and Outs of Polarity
The Mackie DLM12S subwoofer includes a switch
that allows you to quickly invert the polarity of the
subwoofer’s output relative to the input signal it is
receiving from the mixer or other sound source.
But what exactly does that mean? 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 in Figure 1. 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.
When the normal/invert [polarity] switch [5] is
engaged, the original waveform is simply reversed 180˚
[see Figure 2]. 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 polarity switch, 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.
The normal/invert [polarity] switch comes into
play when the DLM12S 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. DLM12S subwoofers are
designed to be used in a broad range of applications.
The flexibility provided by the polarity switch is
necessary to ensure that you are receiving the best
possible sound from your system, regardless of your
setup.
Care and Maintenance
Your Mackie subwoofers will provide many years of
reliable service if you follow these guidelines:
• Avoid exposing the subwoofers to moisture.
If they are set up outdoors, be sure they are
under cover if rain is expected.
• Avoid exposure to extreme cold (below
freezing temperatures). If you must operate
the subwoofers in a cold environment, warm
up the voice coils slowly by sending a low-level
signal through them for about 15 minutes prior
to high-power operation.
• Use a dry cloth to clean the cabinets. Only do
this when the power is turned off. Avoid getting
moisture into any of the openings of the
cabinet, particularly where the drivers are
located.
<–– Time ––>
Figure 1: Normal [0˚]
Amplitude
Amplitude
Figure 2: Invert [180˚]
<–– Time ––>
Polarity Waveforms
