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Small, low-profile surface mounted electret omnidirectional boundary microphone designed for mounting on conference tables, stage floors, and podiums.
Shure Miniature Omnidirectional Boundary Mic - Black Shure Miniature Omnidirectional Boun...
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Microflex® Wired Boundary Microphones from Shure are the smartest boundary microphones yet.  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.

With its omnidirectional polar patterns, the Microflex cartridges give you superior Shure quality sound for every application. In addition, their programmable switches offer the flexibility to be set for Push to Talk, Push to Mute or Push On/Push Off modes. Attractively designed with a low profile, professional appearance, the Microflex Boundary microphones come with an easy to use paint mask for your custom-color installations. Find out why we call the Microflex Boundary microphones "the smart choice" for just about every application. Take a listen today.

Includes an attached 4 meter (12 ft) cable terminated with a 4-pin mini connector and a separate preamplifier. A rubber strain relief is provided for applications where you want to remove the 4-pin mini connector and connect the microphone cable directly to screw terminals in the preamplifier.

Key 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



Product Specifications

Detailed Specifications
Polaroid Pattern Omnidirectional 
Environmental Requirements Operating Temperature Range: -18 to 57 degrees C (0 to 135 degrees F)
Relative Humidity: 0 to 95%
These specifications apply only to the MX391/MX391W microphones when used with the supplied preamplifier. All measurements taken with the microphone mounted on a 76.2 cm x 76.2 cm (30 in. x 30 in.) wooden surface and with the sound source incident at 30 degrees with respect to the surface plane.
Frequency Response 50 to 17,000 Hz
Output Impedance (at 1000 Hz) 180 ohms actual (rated at 150 ohms)
Open Circuit Sensitivity 1 kHz ref. 1 V per Pascal *
Omnidirectional: -21.5 dB (81.4 mV)
All settings -12 dB at 0 gain; *1 Pascal = 94 dB SPL
Maximum Sound Pressure Level (1 kHz at 1% Total Harmonic Distortion, 1 k ohm load)
Omnidirectional: 110.7 dB
All settings +6 dB at 0 gain
Signal to Noise Ratio (referenced at 94 dB SPL) Omnidirectional: 79.5 dB
Equivalent Output Noise (A-weighted) Omnidirectional: 14.5 dB SPL
Dynamic Range at 1 k ohm Load 96.2 dB
100 dB at 0 gain
Common Mode Rejection 45 dB minimum, 10 Hz to 100 kHz
Preamplifier Output Clipping Level -6 dBV (0.5 V)
12 dB at 0 gain
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

Questions & Answers

Shure Miniature Omnidirectional Boundary Mic - Black

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