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

Smart Protect

There are advanced DSP protection mechanisms
designed into the SRM1850 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 SRM1850 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

A 24 dB/octave high-pass filter at 30 Hz just prior
to the low-frequency amplifier 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. The SRM1850 is 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 SRM1850 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.

AC Power

Be sure the SRM1850 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 SRM1850
subwoofer. This is very dangerous.
Owner's Manual
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