Smart Protect; Limiting; Overexcursion Protection; Thermal Protection - Mackie SRM1850 Owner's Manual

Smart Protect

There are advanced DSP protection mechanisms
to safeguard the subwoofers and amplifiers from
inadvertent damage.
The protection circuits are designed to
protect the subwoofers under reasonable
and sensible conditions. Should you choose
to ignore the warning signs [e.g. excessive distortion],
you can still damage the speaker in the subwoofer
by overdriving it past the point of amplifier clipping.
Such damage is beyond the scope of the warranty.

Limiting

The 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

The SRM1850 has a 24 dB/octave high-pass filter
at 30 Hz, while the SRM2850 has a 24 dB/octave
high-pass filter at 32 Hz just prior to the low-frequency
amplifier. This prevents very 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. SRM subwoofers are
designed to be efficient both electrically and thermally.
In the unlikely event of the amplifier overheating,
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 subwoofer resumes normal operation.
If the thermal switch activates, try turning down the
level control a notch or two on the mixing console (or
the back of the subwoofer) 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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SRM1850 • SRM2850 Powered Subwoofers

AC Power

Be sure the subwoofer 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 SRM
subwoofer. This is very dangerous.

Care and Maintenance

SRM 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.