MM-4XP OPERATING INSTRUCTIONS
17
The MM-4XP performs within its acoustical specifications at
normal temperatures when the MM-4XP LED is green, or if
the LED turns yellow for two seconds or less and then turns
green for at least one second. If the LED remains yellow for
longer than three seconds, that loudspeaker enters hard lim-
iting where:
■Increases to the input level have no effect.
■Distortion increases due to clipping and nonlinear driver
operation.
■The driver is subjected to excessive heat and excursion,
which will compromise its life span and may eventually
lead to damage over time.
CAUTION: The MM-4XP LED turns yellow
when the loudspeaker’s signal goes 2 dB
beyond the actual onset of limiting, and indicates a
safe, optimum level has been exceeded. If the
MM-4XP loudspeakers in a system begin to limit
before reaching the required SPL, consider adding
more loudspeakers to the system to achieve the
desired SPL without exposing the loudspeakers to
excessive levels and possible overheating.

Loudspeaker Temperature and Limiting

The MM-4XP LED turns solid yellow when the temperature
of the MM-4XP heatsink reaches 65° C (145° F), indicating
the unit is reaching its maximum heat dissipation and a
reduction in SPL is recommended. While the MM-4XP will
continue to operate while the LED is yellow, the limiter
threshold is lowered to a safe level (causing the output level
to be lowered by 6 dB) to prevent the loudspeaker from
overheating. When the temperature of the MM-4XP heatsink
cools to 50°C (122°F), the LED changes from yellow to green
and the limiter threshold returns to normal.

Clipping (Red)

The MM-4XP LED flashes red when its input signal causes
the amplifier to overload. If the LED flashes red continuously,
the loudspeaker is severely overloaded and a reduction in
the input level is recommended.
CAUTION: If the MM-4XP LED turns solid red
and the loudspeaker continues to output audio,
though at reduced levels, the loudspeaker’s voltage
may have dropped below 25 V DC. Operation of the
loudspeaker under these conditions is not recom-
mended and the loudspeaker’s power supply and
cabling should be verified.

CONNECTING MM-4XP LOUDSPEAKERS TO

THE MPS-488

To connect MM-4XP loudspeakers to the MPS-488:
1. Power off the MPS-488.
2. Connect audio sources (from a mixer or processor) to the
MPS-488 Channel Inputs. Use balanced XLR cables.
3. Use the MPS-488 Link switches to route Channel Inputs
to the desired Channel Outputs.
4. Connect the MM-4XP loudspeakers to the MPS-488
Channel Outputs. Use a composite cable (such as
Belden 1502) wired for both DC power and balanced
audio and outfitted with the appropriate connector:
■For an MPS-488P power supply, use an EN3 5-pin
female to Phoenix 5-pin female cable.
■For an MPS-488E power supply, use an EN3 5-pin
female to EN3 5-pin male cable.
■To join two cables, one with an EN3 5-pin male cable
mount connector to one with an EN3 5-pin female cable
mount connector, use an EN3 5-pin female-to-male
cable coupler (PN 28.163.033.01).
!
!
Cable
coupler