Protection Circuitry; Care And Maintenance - Mackie THUMP212XT Owner's Manual

Protection Circuitry

ThumpXT loudspeakers employ a built-in limiter for
less distortion at peak levels. A dynamic bass response
circuit provides optimal low frequency response
regardless of overall output level. Additional protection
includes automatic thermal shutdown should the amp
overheat. However, with Class-D amp technology, which
is highly-efficient, this should never be a problem.
The protection circuits are designed to
protect the loudspeakers under reasonable
and sensible conditions. Should you choose
to ignore the warning signs [e.g. excessive distortion],
you can still damage the woofer in the loudspeaker
by overdriving it past the point of amplifier clipping.
Such damage is beyond the scope of the warranty.
Limiting
The polymer high frequency driver has its own
compression circuit which helps protect it from
damaging transient peaks. The compressor is
designed to be transparent and is not noticeable
under normal operating conditions.
Overexcursion Protection
A subsonic filter circuit just prior to the power
amplifier prevents ultra-low frequencies from being
amplified. Excessive low-frequency energy can damage
the woofer by causing it to "bottom out," also know
as overexcursion, which is equivalent to a mechanical
form of clipping.
Thermal Protection
All amplifiers produce heat. ThumpXT loudspeakers
are designed to be efficient both electrically
and thermally. In the unlikely event of the amplifier over-
heating, a built-in thermal switch will activate,
muting the signal.
When the amplifier has cooled down to a safe
operating temperature, the thermal switch resets
itself, and the ThumpXT loudspeaker resumes normal
operation.
If the thermal switch activates, try turning down
the level control a notch or two on the mixing console
to avoid overheating the amplifier. Be aware that direct
sunlight and/or hot stage lights may be the culprit
of an amplifier overheating.
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Thump212XT and Thump215XT 1400W Enhanced Powered Loudspeaker Series
AC Power
Be sure the ThumpXT loudspeaker is plugged into
an outlet that is able to supply the correct voltage
specified for your model. It will continue to operate
at lower voltages, but will not reach full power.
Be sure the electrical service can supply enough
amperage for all the components connected to it.
We recommend that a stiff (robust) supply
of AC power be used because the amplifiers place
high current demands on the AC line. The more power
that is available on the line, the louder the speakers
will play and the more peak output power will be
available for a cleaner, punchier bass. A suspected
problem
of "poor bass performance" is often caused by a weak
AC supply to the amplifiers.
Never remove the ground pin on the
power cord or any other component of the
ThumpXT
loudspeaker. This is very dangerous.

Care and Maintenance

Your ThumpXT loudspeakers will provide many years
of reliable service if you follow these guidelines:
• Avoid exposing the loudspeakers 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 loudspeakers
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.