Specifications

ARCHITECTS' AND ENGINEERS' SPECIFICATIONS
The Speaker System shall be an extended range,
two-way speaker system designed for high
sound-pres-
sure-level reproduction of wide frequency range pro-
gram material in sound reinforcement applications.
The Speaker System shall utilize six 8-inch cone-type
speakers with a total speaker cone area of 1097 cm2
(170 in2) and four high-frequency drivers. Pressure
sensitivity of the Speaker System shall be an EIA
rating of 54 dB at
9.2m (30 feet) from 1 milliwatt (equi-
valent to 102 dB at
1.2m--4 feet-with a I-watt input).
The sound power distribution shall be nominally
uniform over a 140" angle in the horizontal plane and
a 90" angle in the vertical plane. The Speaker System
enclosure shall be a bass reflex design to provide
extreme low-frequency enhancement, with
low-fre-
quency speakers column-mounted in a horn-loaded,
front-ported enclosure, and high-frequency drivers
coupled to a single radial horn.
The frequency response of the Speaker System
shall be uniform and peak-free from 40 Hz to 15,000
Hz when driven by a constant-voltage amplifier and
radiating into an acoustical half-space.
In conventional, full-range, single-amplifier opera-
tion, the continuous power rating of the Speaker
System shall be 200 watts maximum (57-volt source)
and the nominal impedance shall be 16 ohms. In
biamplified operation, the low-frequency section shall
accept up to 200 watts of program material and the
high-frequency section up to 100 watts.
The six low-frequency speakers shall be wired in
a series-parallel configuration and mounted in a
column configuration against the front baffle of the
Speaker System. The four high-frequency drivers
shall be wired in a series-parallel configuration at
the top and coupled to a throat adapter assembly
connected to a single radial horn. The high-frequency
drivers shall be wired through an integral passive
crossover network with a crossover frequency of
2600 Hz. A rear-panel LOUDSPEAKER OPERATION
Switch shall provide four selectable high-frequency
level positions of -4,
- 2, 0 and +2 dB for conven-
tional full-range operation, and a
BlAMP position for
biamplified operation. The inputs shall consist of a
pair of parallel-wired phone jacks for (1) conventional
full-range operation, (2) low-frequency biamplified op-
eration, and (3) high-frequency biamplified operation.
The Speaker System enclosure shall be 15.9
mm
(% in.) wood construction covered with black, textured,
scuff-resistant vinyl, and have anodized, solid alu-
minum rear-panel rails. The enclosure shall have an
integral rear-panel handle and two heavy-duty hard
rubber wheels for mobility, and shall contain a cable
storage compartment at the top rear. The radial horn
shall be of high-density, structural urethane foam. A
plug-in
15.2111 (50-foot) speaker cable shall be supplied.
The Speaker System shall measure 1730 mm in height,
495
mm
in width, and 517 mm in depth (68% in. X
19Y2 in. X 20% in.). The weight, including the sup-
plied cable, shall be 64.5 kg (142 Ib).
The operating temperature range of the Speaker
System shall be -7°C to 43°C (20°F to 110°F). The
storage temperature range shall be -29°C to 71°C
(-20°F to 160°F). The Speaker System shall meet
all specifications when operated within the operating
temperature limits.
Any Speaker System not meeting all of the above
specifications, or having a sealed cabinet which pre-
vents internal inspection and servicing, shall be
deemed unacceptable under this specification. The
Speaker System shall be
a Shure Model SR108.