I ?ROFESSIONAL PRODUCTS DATA I
SHURE"C]
2 2 2 H A R T R E Y A V E , E V A N S T O N , I L . , 60204 U.S.A.
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AREA CODE 3 1 2 / 8 6 6 - 2 2 0 0
Copyright 1982, Shure Brothers Inc.
27A1802 (BF)
Cardioid polar pattern and 150 Hz to 10 kHz frequency response for optimum speech pickup
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GENERAL
Microphone Features:
Microphone angled inside foam so cartridge is
approximately an eighth inch from supporting
surface
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Low-profile design eliminates hollow sound caused
by phase cancellation in ordinary tabletop pickup
situations
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Available with either brown or white foam and
matching colored cable to blend with typical surfaces
Designed for altar, conference table, or podium
pickup
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CABLE: SHUREMICRO
SMl8W (Rear View)
SM18B (Front View)
The Shure Models SM18B and SM18W are inconspicuous, low-profile, foam-encased microphones designed
for optimum speech pickup when mounted on an altar,
tabletop, podium, or lectern. The SM18B has a dark
brown foam enclosure and cable; the SM18W has a
white foam enclosure and cable. The microphones have
cardioid (unidirectional) polar characteristics; they are
angled at 10" inside their foam housings to place the
cartridge approximately one-eighth inch from the supporting surface. This low-profile design eliminates the
hollow sound associated with tabletop pickup and
maximizes the output by using the reflected sound
from the tabletop to effectively double the output.
Because surface-reflected sound waves reach the microphones at practically the same time as direct sound
waves, cancellation owing to phase differences between the direct and reflected waves is significantly
reduced, and the two sound waves combine to increase the output by 6 dB.
The physical and acoustic characteristics of the
SM18B and the SM18W make them ideal for use on altars
in front of standing clergy or on conference tables where
ordinary stand-mounted microphones would be visually
distracting. The colors chosen for the foam and cables
are designed for maximum unobtrusiveness; the white
SM18W will be inconspicuous on a white marble or cloth
covered altar; while the brown SM18B will blend with a
brown wood-finished conference table.
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Supplied with right-angle three-pin professional
audio connector (male) for ease of hookup
APPLICATIONS
Place the microphone on a table, altar, or lectern.
Note that, when viewed from the rear, the circular
opening should be nearest the "TOP" of the foam
enclosure (see Figure 4). This position ensures that
the cartridge is in the optimum position for maximizing speech pickup and minimizing cancellation
caused by surface reflections. Aim the front of the foam
(the end away from the cable, see Figure 4) toward the
speaker or lecturer. A seated or standing speaker will
then be within the 15" to 45" angle of maximum pickup
sensitivity. Position the microphone so that it is approximately 0.9m (3 ft.) from the mouth of the speaker or
lecturer at any angle up to 45".
SPECIFICATIONS
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Dynamic
Frequency Response
150 to 10,000 Hz, at 25", I m (39.4 in.) from sound
source, microphone on flat surface (see Figure 1)
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20
50
100
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FREWENCY IN HERTZ
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24000
TYPICAL FREQUENCY RESPONSE
FIGURE 1
Printed i n U.S.A.
Polar Pattern
Cardioid (unidirectional), at I m (39.4 in.) from horizontal sound source, microphone on flat surface (see
Figure 2)
Net Weight (less cable)
110 grams (3.9 oz)
Packaged Weight
338 grams (12 oz)
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ARCHITECTS' SPECIFICATIONS
.--50011.
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........ 5kH1
TYPICAL HORIZONTAL POLAR PATTERN
FIGURE 2
Impedance
Microphone rating impedance is 150 ohms (160 ohms
actual) for connection to microphone inputs rated at
19 to 300 ohms.
Output Level [at 1,000 Hz, 25", l m (39.4 in.) from sound
source, microphone on flat surface]
Open Circuit Voltage . . . . . . . . . . . -75.0 dB (.I8 mV)
0 dB = 1 volt per microbar
Power Level . . . . . . . . . . . . . . . . . . . . . . . . . . -53.0 dB
0 dB = 1 milliwatt per 10 microbars
Phasing
Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3 (see Figure 3).
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CARTRIDGE
CABLE
CONNECTOR
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CODED
,
BLACK
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INTERNAL CONNECTIONS
FIGURE 3
Cable
2.7m (9 ft.) two-conductor shielded, small diameter,
attached (SM18B cable is brown; SMlBW cable is
white) with right-angle three-pin professional audio
connector (male) designed to mate with Cannon XL
series, Switchcraft A3 (Q.G.) series, or equivalent connector.
Case
Elliptical shaped open-cell acoustic foam shock mount
enclosure (SM18B foam is brown; SM18W foam is
white), holds microphone at 10" angle from horizontal
with diaphragm approximately 3.2 mm ('/a in.) from
mounting surface.
Dimensions
See Figure 4.
The microphone shall be a moving coil (dynamic) type
with a frequency response of 150 to 10,000 Hz measured
at 1m (39.4 in.), 25" from a sound source and mounted
on a flat surface. The unit shall have a free field cardioid
polar characteristic. The cancellation at the sides shall
be 6 dB while the cancellation at the rear shall be 15 to
20 dB. The microphone shall have low impedance with
a rated impedance of 150 ohms for connection to microphone inputs rated at 19 to 300 ohms.
The microphone output shall be -53.0 dB where 0 dB
= 1 milliwatt per 10 microbars.
The microphone shall be designed for use on a flat
surface such as an altar or tabletop. The microphone
shall be set at 10" from the horizontal in an open-cell
acoustic foam shock mount enclosure that shall be brown
or white. The microphone shall be equipped with a 2.7m
(9 ft.) two-conductor shielded cable, either brown or
white to match the enclosure. The cable shall be terminated with a right-angle, three-pin professional audio
connector (male) designed to mate with Cannon XL
series, Switchcraft A3 (Q.G.) series, or equivalent connector.
The overall dimensions of the microphone shall be
44.5 mm (1% in.) in height, 47.6 mm (1% in.) in width,
and 89 mm (3% in.) in depth.
The microphone shall be the Shure Model SMIBB,
SMIBW, or equivalent.
476mm
REPLACEMENT PARTS
SM18B
Foam Enclosure . . . . . . . . . . . . . . . . RK204F
Cable and Connector . . . . . . . . . . . .
C92
Cartridge . . . . . . . . . . . . . . . . . . . . . .
SM18W
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RK205F
C93
R105
R105
Cartridge Case, Top . . . . . . . . . . . . . 65A1271
65A1271
Cartridge Case, Bottom . . . . . . . . . . 65A1270
65A1270
GUARANTEE
This Shure product is guaranteed in normal use to
be free from electrical and mechanical defects for a
period of one year from date of purchase. Please
retain proof of purchase date. This guarantee includes
all parts and labor. This guarantee is in lieu of any
and all other guarantees or warranties, express or implied, and there shall be no recovery for any consequential or incidental damages.
11-7/81"!
64mm
rTOP
I-ionln)
FRONT
SUPPORTING
SURFACE
89mm
(3-1/2in!
CABLE
2 7m
OVERALL DIMENSIONS
FIGURE 4
SHIPPING INSTRUCTIONS
Carefully repack the unit and return it prepaid to:
Shure Brothers Incorporated
Attention: Service Department
1501 West Shure Drive
Arlington Heights, Illinois 60004
If outside the United States, return the unit to your
dealer or Authorized Shure Service Center for repair.
The unit will be returned to you prepaid.
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