2
MICROPHONE SPECIFICATIONS
Polar Pattern (Figure 4)
Cardioid (MX391/C, MX391W/C, MX391LP/C, MX391WLP/C)
Supercardioid (MX391/S, MX391W/S, MX391LP/S, MX391WLP/S)
Omnidirectional (MX391/O, MX391W/O, MX391LP/O,
MX391WLP/O)
Environmental Requirements
Operating Temperature Range: –18
°
C to 57
°
C (0
°
F to 135
°
F)
Relative Humidity: 0 to 95%
Dimensions
See Figure 5
Wiring Diagram (Figure 2)
PIN 2 = RED LEAD
PIN 1 = SHIELD (use only HALF of
the shield, the other half solder to
cable clamp)
PINS 3 and 4 = BLACK LEAD
(jumped)
4
3
1
2
WIRING DIAGRAM
FIGURE 2
PREAMPLIFIER SPECIFICATIONS
These specifications apply only to the MX391/MX391W micro-
phones when used with the supplied preamplifier. All measurements
taken with the microphone mounted on a wooden surface 76.2 cm
x 76.2 cm (30 in. x 30 in.) and with the sound source incident at 30
°
with respect to the surface plane.
Frequency Response (Figure 3)
50 to 17,000 Hz
Output Impedance (at 1000 Hz)
Rated at 150
Ω
(180
Ω
actual)
Open Circuit Sensitivity
Cartridge Type
1 kHz ref. 1 V per
Pascal *
Cardioid
–29.6 dB (33.5 mV)
Supercardioid
–28.3 dB (38.5 mV)
Omnidirectional
–21.5 dB (81.4 mV)
*1 Pascal = 94 dB SPL
Maximum Sound Pressure Level
(1 kHz at 1% Total Harmonic Distortion, 1 k
Ω
load)
Cardioid: 118.8 dB
Supercardioid: 117.5 dB
Omnidirectional: 110.7 dB
Signal to Noise Ratio (referenced at 94 dB SPL)
Cardioid: 71.4 dB
Supercardioid: 72.7 dB
Omnidirectional: 79.5 dB
Equivalent Output Noise (A-weighted)
Cardioid: 22.6 dB SPL
Supercardioid: 21.3 dB SPL
Omnidirectional: 14.5 dB SPL
Dynamic Range
at 1 k
Ω
Load
96.2 dB
Common Mode Rejection
45 dB minimum, 10 Hz to 100 kHz
Preamplifier Output Clipping Level
–6 dBV (0.5 V)
Polarity
Positive sound pressure on diaphragm produces positive voltage
on pin 2 relative to pin 3 of the preamplifier XLR output connector.
Power Requirements
11 to 52 Vdc phantom
2.0 mA current consumption
Certification
Eligible to bear CE Marking. Conforms to European EMC
Directive 89/336/EEC. Meets applicable tests and performance
criteria in European Standard EN55103 (1996) parts 1 and 2, for
residential (E1) and light industrial (E2) environments.
REPLACEMENT PARTS
Omnidirectional Cartridge
R183B
. . . . . . . . . . . . . . . . . . . . . . . . . .
Supercardioid Cartridge
R184B
. . . . . . . . . . . . . . . . . . . . . . . . . . .
Cardioid Cartridge
R185B
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preamplifier Kit
RK183PK
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacement Cable Kit (black)
C123
. . . . . . . . . . . . . . . . . . . . . .
Replacement Cable Kit (white)
C125
. . . . . . . . . . . . . . . . . . . . . .
NOTE: For technical data by Fax, phone 1-800-488-3297 and follow
the recorded instructions. For additional technical assistance,
phone Shure at (847) 866-2200. In Europe, phone 49-7131-72140.
SHURE, the Shure logo, and MICROFLEX are registered trade-
marks of Shure Incorporated. Tini Q-G is a registered trademark of
Switchcraft Incorporated.
