Microflex MX391 Series Boundary Microphones

Model MX391 Boundary Microphone User Guide

MICROFLEX MX391 SERIES

BOUNDARY MICROPHONES

Shure Microflex→ MX391 Series microphones are small, surface- mounted electret condenser microphones designed for mounting on conference tables, stage floors, and lecterns. Their high sensitivity and wide frequency range make them especially suitable for picking up speech and vocals in sound reinforcement and recording applications.

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

•New RF filtering

MODEL VARIATIONS

MX391 and MX391W (white) models have an attached 4 meter (12 ft) cable terminated with a 4-pin mini connector and a separate preamplifier, as pictured above in black.

Microflex→ boundary microphones come with one of three inter- changeable cartridges, as indicated by the model number (found on the bottom of the microphone base).

MX391/C series. Cardioid pickup pattern for general sound reinforce- ment applications. Pickup angle (-3 dB) = 130°.

MX391/S series. Supercardioid pickup pattern for sound reinforce- ment applications requiring narrow or more distant coverage. Pickup angle (-3 dB) = 115°.

MX391/O series. Omnidirectional pickup pattern for recording or re- mote monitoring applications. Pickup angle = 360°.

PERMANENT INSTALLATION

1.Remove the grille from the microphone base by loosening the sin- gle screw on top of the grille, (Figure 1).

WARNING: Do not attempt to detach the cable from the microphone interface.

2.Re-route the cable through the bottom exit hole and pull snug.

3.Use the supplied template (Figure 3) to drill screw holes and a bottom exit hole in the mounting surface.

4.Thread the 4-pin mini connector and cable through the hole of the table.

5.Set the grille back into place and thread the screw through the perforated metal grille and into the microphone interface and tighten.

REPAINTING THE MX391 SERIES

Before applying paint to the MX391 series, remove the grille from the base, remove the foam from the inside of the grill, and mask the microphone cartridge and interface. Also mask the cable where necessary.

Screw Hole

Microphone Interface

Slit

Screw Hole

RE-ROUTING THE CABLE

FIGURE 1

ADJUSTING PREAMP GAIN: MX391 AND MX391W ONLY (FIGURE 4)

MX391 and MX391W microphones include an adjustable gain pream- plifier, allowing the user to specify a 12 dB or 0 dB gain setting. The preamp ships at de 12 dB setting. To reduce the signal gain at the MX391B and MX391W preamplifier by 12dB, replace the gain resis- tors to the 0dB setting, (Table 4A).

RF FILTERING

MX391 Series must be used with RK100PK preamplifier in order to op- timize RF immunity.

Note: Cable shield is NOT connected to pin 1 in the TA4F mini- connector. If you are connecting this microphone to a plastic transmitter, please modify the cable to connect the shield to pin 1. Contact Shure Applications Engineering for assistance.

©2007, Shure Incorporated		Printed in U.S.A.
27E3027 (Rev. 2)

MX391 specifications

The Shure MX391 is a modern solution for professional audio recording and communication in various settings. Ideal for conference rooms, boardrooms, and performance venues, the MX391 is designed to deliver high-quality audio capture while maintaining a low profile. This boundary microphone is engineered to pick up sound from all directions, making it perfect for capturing conversations around a table or ambient sounds in a room.

One of the standout features of the MX391 is its superior audio performance. It employs a cardioid pickup pattern, ensuring that it captures sound from the front while rejecting noise from the sides and rear. This design minimizes background noise and focuses on the primary audio source, making it an excellent choice for environments where multiple people are speaking or where ambient noise is a concern.

The MX391 is equipped with a built-in preamplifier, which ensures high sensitivity and a wide dynamic range. This preamplifier provides clean audio signals, allowing users to capture sound details without distortion. Additionally, the microphone features a frequency response range of 20 to 20,000 Hz, ensuring it captures a full spectrum of sound, from deep lows to clear highs.

Another technological advantage of the Shure MX391 is its low-profile design. The microphone can be discreetly mounted on a table or surface, minimizing visual distractions during presentations or discussions. It is available in different finishes to match the aesthetics of various environments, further enhancing its versatility.

The MX391 is also easy to install and integrate into existing audio systems. It can be connected to various Shure wireless systems or other professional audio equipment, thanks to its standard XLR output. This flexibility makes it a popular choice for audio professionals who require reliable and high-quality audio solutions.

Moreover, durability is a hallmark of the Shure brand, and the MX391 is no exception. It is constructed with high-quality materials designed to withstand the rigors of frequent use, ensuring long-lasting performance in demanding environments.

In summary, the Shure MX391 boundary microphone combines high sensitivity, cardioid pickup pattern, and low-profile design, making it an ideal choice for professional audio applications. Whether for corporate meetings, educational settings, or stage performances, the MX391 delivers exceptional sound quality and reliability, meeting the needs of audio professionals and users alike.