L-Acoustics 108P, Operator'S Manual

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L-ACOUSTICS P Series Manual V2.1 7/12/2007
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1.4 108P DESCRIPTION
The 108P is a self-powered, bi-amplified, two-way coaxial full range loudspeaker containing one
direct radiating, bass reflex-loaded, weather-resistant 8-inch low frequency transducer and one 25
mm (1.0 inch) exit, 44 mm (1.7 inch) voice coil diameter, polyester diaphragm, compression driver.
The cone body of the 8-inch low frequency component provides pattern control loading for the
compression driver and yields a 100-degree conical directivity pattern that is axi-symmetric. As a full
range system, frequency response is 65 Hz to 20 kHz with less than +/- 3 dB variation and the
usable bandwidth is 50 Hz to 22 kHz (-10 dB).
The 108P contains internal digital signal processing electronics and a two-channel power amplifier.
The power amplifier provides 500 W continuous (1 kHz, 0.5% THD) into 4 ohms and 250 W
continuous (1 kHz, 0.5% THD) into 8 ohms for powering low and high frequency transducers,
respectively. The power amplifier provides thermal protection, short-circuit/overload output
protection, clip and RMS signal limiting. Digital processing electronics also provides corrective
component and system equalization, component time alignment and crossover filtering.
Four presets are selectable via rear-panel push button switch with the following characteristics: FILL
has nominally flat frequency response when the loudspeaker is used under freefield conditions;
FRONT has +3 dB low and high frequency shelving characteristics under freefield conditions;
MONITOR has nominally flat response under half-space loading conditions; X-OVER provides a 100
Hz high pass filter and +3 dB high frequency shelving characteristics for use of the 108P with the L-
ACOUSTICS SB15P self-powered subwoofer. Connection to the 108P is made via two parallel XLR
connectors and gain is controllable via rear panel volume potentiometer. AC power connectors are
PowerCon type and 115V or 230V operation is selectable via rear panel rotary switch.
The 108P has a truncated wedge shape with a curved front profile. Dimensions are 42.1 cm (16.6 in)
high, 25.0 cm (9.8 in) wide by 29.9 cm (11.8 in) deep. When used as a floor monitor, the front baffle
of the enclosure is oriented at 30° with respect to vertical. Enclosure weight is 12.8 kg (28.2 lbs) and
cabinet construction consists of 15 mm (0.6 in) and 18 mm (0.7 in) Baltic birch plywood with joints
that are sealed, screwed and rabbeted. The finish is maroon gray, high resiliency paint and the front
of the 108P is protected by a black powder-coated 1.5 mm (0.06 in) thick steel grill covered with
acoustically-transparent grille cloth. The 108P has a 35 mm (1.38 in) diameter pole mount socket
mounted on the bottom side and a recessed plate on the top side for rigging the enclosure in
conjunction with an adjustable U-bracket assembly.
Figure 11: 108P (floor monitor orientation)