Pricing and availability

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Average Price: $232

Standard/Professional

$100

$401+

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Based on price data from 4 merchants for "Shure MX391/O Microflex Omnidirectional Boundary Mic w/ 12' 3-Pin XLR Cable". Prices shown reflect NEW condition. Tracking began Apr 2, 2026.

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Description

In the world of professional audio, the Shure MX391/O Microflex Omnidirectional Boundary Mic is your go-to tool for capturing pristine sound in a discreet package. Whether it's a corporate boardroom, an educational setting, or a house of worship, this boundary mic seamlessly integrates to deliver crisp, intelligible speech every time. Engineered with a balanced, transformerless output, it minimizes unwanted noise and interference, ensuring your audio remains uncolored and pure.

The MX391/O stands out with its ability to swap between three condenser cartridges: omnidirectional, cardioid, and supercardioid. This feature allows you to tailor the mic to any acoustical environment, making it versatile for a variety of applications. Its sleek, low-profile design means it won't distract from the presentation or performance, maintaining a professional aesthetic.

Included is a 12-foot cable terminating in a 3-pin XLR, accompanied by a separate preamplifier, making it ready to connect to your existing audio setup. This inline preamp is built with high-level RF filtering, significantly reducing the risk of interference from surrounding electronic devices. The MX391/O doesn't include mute switches, keeping it always ready to capture every word, ensuring speakers are consistently heard without interruption.

Key Features:

  • Omnidirectional condenser cartridge for 360-degree sound capture
  • Interchangeable mic capsules for tailored audio capture
  • Transformerless output for reduced noise and interference
  • Sleek, unobtrusive design for professional environments
  • Includes 12-foot cable with 3-pin XLR and inline preamp
  • High RF filtering in preamp for reduced radio interference

Product specs

Microphone Type Electret Condenser
Polar Pattern Omnidirectional
Frequency Response 50Hz-17kHz
Max SPL 111dB SPL
Output Impedance 180 ohms
Signal to Noise Ratio 80dB A weighted
Self Noise 15dB A weighted
Cable Length 12 ft.
Connector Shure TA4

FAQs

What is the primary application for the Shure MX391/O Microflex Omnidirectional Boundary Microphone?

The Shure MX391/O is designed primarily for capturing speech in conference rooms and similar environments, providing clear and uncolored sound across the vocal range.

How does the omnidirectional polar pattern of the Shure MX391/O affect its performance?

The omnidirectional polar pattern captures sound equally from all directions, making it ideal for picking up multiple speakers in a room without needing precise positioning.

Is the Shure MX391/O suitable for long cable runs?

Yes, the Shure MX391/O features a balanced, transformerless output, which increases immunity to noise over long cable runs, ensuring clear audio transmission.

What kind of connector does the Shure MX391/O use?

The Shure MX391/O uses a Shure TA4 connector, compatible with various professional audio setups.

Does the Shure MX391/O come with interchangeable cartridges?

Yes, the Shure MX391/O allows for interchangeable cardioid, supercardioid, and omnidirectional cartridges, offering flexibility for different recording applications.

Reviews

PROS

  • Compact and unobtrusive design suits non-traditional setups

  • High sensitivity captures clear audio even from several feet away

  • Solid build quality with an elegant appearance

  • Includes a nice inline pre-amp for enhanced audio

  • Excellent for group discussions, capturing multiple voices effectively

  • Performs well with various audio mixers

  • Good value for the price, especially for conference settings

CONS

  • Can transmit surface noise from desks or tables

  • Feedback can be challenging to manage at times

  • Lacks a mute button, which may be inconvenient for some users

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