MX391/C

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.

MX391/C Cardioid, Black

MX391: 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 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
  
  

Polar Pattern

Cardioid (MX391/C, MX391W/C)

Supercardioid (MX391/S, MX391W/S)

Omnidirectional (MX391/O, MX391W/O)

Environmental Requirements

Operating Temperature Range: -18 to 57 degrees C (0 to 135 degrees F)

Relative Humidity: 0 to 95%

Dimensions

See User Guide

PREAMPLIFIER SPECIFICATIONS MX391 ONLY

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 *

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