Microflex
®
MX391BP Series
Boundary Microphones User Guide
27D3047 (Rev. 5)
©
2005, Shure Incorporated
Printed in U.S.A.
GENERAL
Shure Microflex
®
MX391BP series microphones are small, sur-
face mounted electret condenser microphones designed for
mounting on conference tables, stage floors, and lecterns. Their
high sensitivity and wide frequency response make them especial-
ly suitable for picking up speech and vocals in sound reinforce-
ment and recording applications. The supplied MX1BP bat-
tery-powered preamplifier allows use of these microphones in sit-
uations where phantom power is not available.
FEATURES
•
Flat frequency response across the vocal range for uncolored
sound
•
Interchangeable cardioid, supercardioid, and omnidirectional
cartridges that provide optimal choice for anyapplication
•
Sleek, low-profile design for unobtrusive appearance
•
Balanced transformer output providesfor for increased
immunity to noise over long cable runs.
•
MX1BP preamplifier features mic on/mute switch and power
LED indicator; works on either a 9 V battery or phantom power.
MODEL VARIATIONS
MX391BP
models have a microphone an attached to a 43.7 meter
(12 ft) cable terminated with a female 4-pin mini connector. The
MX1BP preamplifier has an attached 3.7 m (12 ft) cable terminat-
ed with a 3-pin male XLR connector.
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 or MX391W/C
or MX391BLP/C.
Cardioid pickup pat-
tern for general sound reinforcement applications. Pickup angle (-
3 dB) = 130
°
.
MX391/S or MX391W/S or MX391BLP/S.
Supercardioid pickup
pattern for sound reinforcement applications requiring narrow or
more distant coverage. Pickup angle (-3 dB) = 115
°
.
MX391/O or MX391W/O or MX391BLP/O.
Omnidirectional pick-
up pattern for recording or remote monitoring applications. Pickup
angle = 360
°
.
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:
To re-route the microphone cable through the bottom exit hole,
use the following steps:
1. Remove the grille from the microphone base by loosening the
single screw on top of the grille.
2. Remove the 4-pin mini connector from the end of the cable by
cutting the cable just below the connector.
WARNING:
Do not attempt to detach the cable from the micro-
phone interface.
3. Re-route cable as shown in Figure 1.
4. After threading the cable through the bottom exit hole in the
mounting surface, re-attach the 4-pin mini connector
(see Figure 4).
REPAINTING THE MX391BP
Before applying paint to the MX391BP series, remove the grille
from the base, remove the foam from the inside of the grille, and
mask the microphone cartridge and interface. Also, mask the ca-
ble where necessary.
BATTERY INSTALLATION
(Figure 2)
1. Move the Mic Mute/On switch on the preamplifier to the Mute
position.
2. Press down on the OPEN side of the battery compartment cov-
er. Slide the cover back and flip it open.
3. Insert a 9 V battery as shown, observing proper battery polarity
(“+/-”). Close the battery compartment cover.
4. Move the Mic Mute/On switch on the preamplifier to the On po-
sition when ready to use the system.
NOTE
: A minimal power drain occurs while the 9 V battery is
installed. To conserve battery life, remove the battery when the
preamplifier is not in use.
Service
Loop
Screw Hole
Screw Hole
Microphone
Interface
Strain Relief Post
Bottom
Exit Hole
Top Exit
Hole
FIGURE 1
– +
FIGURE 2
