Shure MX391/C Microflex Cardioid Condenser Boundary Microphone - Black

MX391/C

There's never been smarter boundary microphones than the Microflex models from Shure. With many models to choose from, 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 one of the new interchangeable condenser cartridges. Available in Cardioid Supercardioid and Omnidirectional polar patterns, the Microflex cartridges give you superior Shure quality sound options for every installation. 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.

The MX391/C 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.

Features:

• Flat frequency response across the vocal range for uncolored sound
• Cardioid polar pattern - interchangeable with supercardioid and omnidirectional cartridges providing optimal choice for each application
• Sleek, low-profile design for unobtrusive appearance
• Balanced, transformerless output for increased immunity to noise over long cable runs
• Detachable preamp with XLR
• White or Black finish that blends unobtrusively with most surroundings

• House of Worship
• Courtrooms
• Conference Tables

Polar Pattern
Cardioid
Environmental Requirements
Operating Temperature Range: -18 to 57 degrees C (0 to 135 degrees F)
Relative Humidity: 0 to 95%

Preamp Specifications:

 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 *

Cardioid: -29.6 dB (33.5 mV)

Supercardioid: -28.3 dB (38.5 mV)

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)

Cardioid: 118.8 dB

Supercardioid: 117.5 dB

Omnidirectional: 110.7 dB

All settings +6 dB at 0 gain

 

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 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

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.