Meyer Sound M1D - Manual (Page 15)

8
CHAPTER 2
9
CHAPTER 2
M1D and M1D-Sub Limiting at Work
The M1D and M1D-Sub loudspeakers perform within their
acoustical specifications and operate at a normal tempera-
ture if the limit LEDs are on for no longer than two seconds,
and off for at least one second. If either LED remains on for
longer than three seconds, that channel incurs hard limiting
with the following negative consequences:
 Increasing the input level will not increase the volume.
 The system distorts due to clipping and nonlinear driver
operation.
 Unequal limiting between the low and high frequency
drivers can alter the frequency response (M1D).
 The lifespan of the drivers is reduced because they are
subjected to excessive heat.
While the limiters protect the system under overload
conditions and exhibit smooth sonic characteristics, it is
recommended that you do not drive the M1D or M1D-Sub
loudspeaker into continuous limiting.
NOTE: The Limit LEDs indicate when the
safe power level is exceeded. For example,
if an entire system of M1Ds begins to limit before
reaching the required sound pressure level (SPL),
you should consider adding more loudspeakers to
the array.
The limiters cease operation when the level in the chan-
nel returns to normal. Limiters have no effect on the signal
when the LED is inactive.
AMPLIFIER COOLING SYSTEM
The M1D/M1D-Sub amplifier employs a combination of
natural convection and forced air in its cooling system. The
large heatsink used in the amplifier allows natural convec-
tion cooling from air flowing over the fins. A low noise fan
forces air to the fins, keeping the temperature on the ampli-
fier low even when the loudspeakers are being used at high
ambient temperature, in tightly packed conditions and/or at
high continuous levels.
If the temperature of the heatsink reaches 75° C (167° F),
the fan switches to high speed and the On/Temp. LED on
the rear panel turns from green (On) to red (Temp.). The unit
continues to operate normally even if the On/Temp LED is
red.
! CAUTION: To keep the heatsink from getting
too hot, ensure proper ventilation around the
loudspeaker, especially when using the loudspeak-
ers in tightly packed conditions.
When the heatsink temperature decreases to 65° C (145° F),
the On/Temp. LED changes from red to green.
! CAUTION: The heatsink can reach tem-
peratures up to 75° C (167° F) during normal
operation. Use extreme caution when approaching
the rear of the cabinet.