By: Shure
Microphones, Headphones & Wireless systems
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Microflex Boundary Microphone
The Shure Microflex Microphone Series MX 391 is equipped with features like programmable, silent membrane switches, logic inputs and outputs, and LED indicators, Microflex® Boundary Microphones are the high-quality solution for a range of applications such as altars, boardrooms and distance learning centers. Every Microflex Boundary microphone features a choice of interchangeable condenser cartridges. MX-391: Includes attached 4 meter (12 ft) cable terminated with a 4-pin mini connector and separate preamplifier. A rubber strain relief is provided for applications that require removing the 4-pin mini connector and connecting the mic cable directly to screw terminals in the preamplifier.
Flat frequency response across the vocal range for uncolored sound
Interchangeable cartridges that provide a choice of polar pattern for each application
Sleek, low-profile design for unobtrusive appearance
RF filtering
Type Condenser (electret bias)
Frequency Response 50–17000 Hz
Polar Pattern MX391/O= Omnidirectional; MX391/C= Cardioid; MX391/S= Supercardioid
Output Impedance EIA Rated at 150 O (180 O actual)
Output Configuration Active balanced
Sensitivity (at 1 kHz , open circuit voltage) Cardioid= –30 dBV/Pa (33.5 mV); Omnidirectional= –22 dBV/Pa (81.4 mV); Supercardioid= –28 dBV/Pa (38.5 mV); 1 Pascal=94 dB SPL
Maximum SPL (1 kHz at 1% THD, 1 kO load) Cardioid= 119 dB; Omnidirectional= 111 dB; Supercardioid= 118 dB
Equivalent Output Noise (A-weighted) Cardioid= 23 dB SPL; Omnidirectional= 15 dB SPL; Supercardioid= 21 dB
Signal-to-Noise Ratio (referenced at 94 dB SPL at 1 kHz) Cardioid= 71 dB; Omnidirectional= 80 dB; Supercardioid= 73 dB
Dynamic Range (1 kO load at 1 kHz) 96 dB
Common Mode Rejection (10 Hz–100 kHz) 45 dB minimum
Preamplifier Output Clipping Level (1% THD) –6 dBV (0.5 V)
Polarity Positive sound pressure on diaphragm produces positive voltage on pin 2 relative to pin 3 of output XLR connector
Logic Connections LED IN: Active low (=1.0V), TTL compatible; Absolute maximum voltage= -0.7V to 50V
Environmental Conditions Operating Temperature= -18–57 °C (0–135 °F); Storage Temperature= -29–74 °C (-20–165 °F); Relative Humidity= 0–95%
Power Requirements 11–52 Vdc phantom, 2.0 mA

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Prices and specifications subject to change without notice.