EXP X-800C, Operating Instructions Manual, Page: 15 / 28

X-800C OPERATING INSTRUCTIONS
15
The X-800C performs within its acoustical specifications at
normal temperatures when the SUB Limit LED is unlit, or if
the LED is lit for two seconds or less and then turns off for at
least one second. If the LED remains lit for longer than three
seconds, the loudspeaker enters hard limiting where:
■
Increases to the input level have no effect.
■
Distortion increases due to clipping and nonlinear driver
operation.
■
The drivers are subjected to excessive heat and excur-
sion, which will compromise their life span and may
eventually lead to damage over time.
CAUTION: The SUB Limit LEDs indicates
when a safe, optimum level is exceeded. If an
X-800Cs begins to limit before reaching the required
SPL, consider adding more subwoofers to the sys-
tem.
NOTE: The X-800C subwoofer uses an optical
limiter that adds no noise and has no effect on
the signal when the limiter is not engaged and the
SUB Limit LED is not lit.
Excursion Clamp LED
The X-800C drivers are protected from over-excursion by an
Excursion Clamping circuit, indicated by the Exc Clamp
LED. The circuit does not have attack or release time con-
stants and provides instantaneous braking for the drivers
without the pumping effects commonly exhibited by com-
pressors and limiters.
The Excursion Clamping circuit uses sophisticated filters to
minimize the distortion normally caused by clamping and
clipping. As the X-800C’s input signal is increased beyond
the clamping point, the output signal remains at a fixed
level, protecting the drivers and minimizing negative sonic
effects. The X-800C operates normally and safely when the
Exc Clamp LED is on for no longer than two seconds, and
off for at least one second.
INPUT POLARITY SWITCH
The X-800C includes an Input Polarity switch on its rear
panel that toggles the polarity of the source signal. When
the switch is in the UP position, pin 2 is hot relative to pin 3,
resulting in a positive pressure wave when a positive signal
is applied to pin 2. When the switch is in the DOWN posi-
tion, pin 3 is hot relative to pin 2, resulting in a positive pres-
sure wave when a positive signal is applied to pin 3.
NOTE: The Input Polarity switch does not
affect the signal coming from the Loop output
connector. The Loop output connector is wired in
parallel to the Input connector and transmits the
unbuffered source signal (even when the loudspeaker
is powered off).
AMPLIFIER COOLING SYSTEM
The X-800C uses a forced-air cooling system with two fans
(one variable-speed, ultra low-noise primary fan and one
reserve fan) to prevent the amplifier module from overheat-
ing. The fans draw air in through ducts on the front of the
cabinet, over the heat sink, and out the rear of the cabinet.
Because dust does not accumulate in the amplifier circuitry,
its life span is increased significantly.
!
X-800C Input Polarity Switch
Airflow for the X-800C
10K
:
Balanced
Input Polarity
2 +
3 +
Heat sink/
amplifier
Air filter
Power
supply
Air
intake
Low-
noise
fans