Shure MICROFLEX MX391 Series User Manual

MICROFLEX MX391 SERIES
BOUNDARY MICROPHONES
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Shure Microflex MX391 Series microphones are small, surface-
mounted electret condenser microphones designed for mounting on
conference tables, stage floors, and lecterns. Their high sensitivity
and wide frequency range make them especially suitable for picking up
speech and vocals in sound reinforcement and recording applications.
FEATURES
• Flat frequency response across the vocal range for uncolored
sound
• Interchangeable cardioid, supercardioid, and omnidirectional
cartridges that provide optimal choice for each application
• Sleek, low-profile design for unobtrusive appearance
• Balanced, transformerless output for increased immunity to
noise over long cable runs
MODEL VARIATIONS
MX391 and MX391W (white) models have an attached 4 meter (12 ft)
cable terminated with a 4-pin mini connector and a separate preamplifier,
as pictured above in black. A rubber strain relief is provided for applica-
tions where you want to remove the 4-pin mini connector and connect the
microphone cable directly to screw terminals in the preamplifier.
MX391LP and MX391WLP (white) models have an attached 4
meter (12 ft) cable terminated with a 4-pin mini connector, but do not
include a preamplifier. These models are solely for use with a Shure
wireless body-pack transmitter.
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Microflex boundary microphones come with one of three inter-
changeable cartridges, as indicated by the model number (found on
the bottom of the microphone base).
MX391/C series. Cardioid pickup pattern for general sound rein-
forcement applications. Pickup angle (-3 dB) = 130°.
MX391/S series. Supercardioid pickup pattern for sound reinforce-
ment applications requiring narrow or more distant coverage. Pickup
angle (-3 dB) = 115°.
MX391/O series. Omnidirectional pickup pattern for recording or
remote monitoring applications. Pickup angle = 360°.
2003, Shure Incorporated
©
27C3027 (Rev. 3)
Model MX391 Boundary Microphone
PERMANENT INSTALLATION
Screw holes in the microphone base and a bottom exit hole for the
microphone cable are provided for permanent installation of the
boundary microphone. To re-route the microphone cable through the
bottom exit hole, use the following steps (Figure 1):
1. Remove the grille from the microphone base by loosening the sin-
gle screw on top of the grille.
2. Remove the 4-pin mini connector from the end of the cable by cut-
ting the cable just below the connector
WARNING: Do not attempt to detach the cable from the
microphone interface.
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3. ecure the cable with your thumb or finger so that it does not
come loose from the strain-relief posts as you thread the cable out
from the rear exit hole.
4. Re-route the cable through the bottom exit hole and pull snug.
IMPORTANT: Be sure the cable is pressed firmly down
between the strain relief posts before replacing the grill.
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5. et the grille back into place and thread the screw through the
perforated metal grille and into the microphone interface and
tighten.
6. Use the supplied template (Figure 3 on page 9) to drill screw
holes and a bottom exit hole in the mounting surface.
7. After threading the cable through the bottom exit hole in the
mounting surface, either re-attach the 4-pin mini connector (Fig-
ure 2 on page 2) or wire the cable to the screw terminals in the
preamplifier (use the supplied rubber strain relief to secure the
connection).
NOTE: For detailed instructions on re-attaching the 4-
pin mini connector, contact the Shure Applications
Group.
REPAINTING THE MX391 SERIES
Before applying paint to the MX391 series, remove the grille from
the base, remove the foam from the inside of the grill, and mask the
microphone cartridge and interface. Also mask the cable where nec-
essary.
Microphone Interface
Service Loop
Screw Hole
RE-ROUTING THE CABLE
ADJUSTING PREAMP GAIN: MX391 AND MX391W ONLY
(FIGURE 4 ON PAGE 9)
MX391 and MX391W microphones include an adjustable gain
preamplifier, allowing the user to specify a 12 dB or 0 dB gain setting.
The preamp ships at the 12dB setting. Gain may be decreased by
12dB by moving the preamp jumpers to the 0dB setting.

User Guide

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Screw Hole
Strain Relief Post
FIGURE 1
Printed in U.S.A.