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Shure MX391 Microflex Supercardioid Boundary Microphone (White)

BH #SHMX391WAS • MFR #MX391W-A/S
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Shure MX391 Microflex Supercardioid Boundary Microphone (White)
Key Features
  • Supercardioid Pickup Pattern
  • No Mute Switch
  • Interchangeable Mic Capsule
  • Preamp with XLR Output
Styled in white, this Shure MX391 is a Microflex supercardioid boundary microphone. It's easy to use, features an inline preamp, and offers interchangeable mic capsules. It's designed to pick up speech in a manner preserving its intelligibility. The mic is well suited for sound reinforcement and recording applications in boardrooms, conference centers, educational settings, houses of worship, and more.
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Shure MX391 Overview

Styled in white, this Shure MX391 is a Microflex supercardioid boundary microphone. It's easy to use, features an inline preamp, and offers interchangeable mic capsules. It's designed to pick up speech in a manner preserving its intelligibility. The mic is well suited for sound reinforcement and recording applications in boardrooms, conference centers, educational settings, houses of worship, and more.

A Streamlined, Low-Profile Solution
  • The compact, low-profile microphone is designed to be surface-mounted on conference tables, stage floors, and lecterns.
  • The sleek, unobtrusive form factor stays out of the way of panelists and presenters, making it a smart solution for video conferencing.
  • The MX391 doesn't offer mute switches, so speakers can't mute themselves—the mic is always ready to capture every moment in a panel discussion or presentation.
Interchangeable Mic Capsule Tailored for Speech and Vocals
  • The condenser microphone is optimized for crisp, clear speech.
  • The mic's supercardioid pickup pattern focuses audio capture tightly on the speaker directly in front on the mic, reducing unwanted noise and feedback.
  • An interchangeable mic capsule design allows you to swap out the supercardioid capsule for a cardioid or omnidirectional capsule for applications requiring a more forgiving pickup pattern (two people sharing a single mic, for example).
Inline Preamp with XLR Output
  • Included is an inline preamp with a standard 3-pin XLR output ready to plug into a PA system, mixer, or recorder capable of supplying 12 to 48V phantom power needed to power the mic.
  • The preamp offers a high level of RF filtering, making the mic substantially less susceptible to unwanted radio interference.
UPC: 042406577144

Shure MX391 Specs

Key Specs
Microphone Type
Boundary
Polar Pattern
Supercardioid
Element Type
Electret Condenser
Controls
No
Frequency Response
50 Hz to 17 kHz
Maximum SPL
118 dB
Analog Output
1x XLR 3-Pin Male
Power Sources
Phantom Power
Microphone
Microphone Type
Boundary
Polar Pattern
Supercardioid
Element Type
Electret Condenser
Sound Field
Mono
Orientation
N/A to Boundary Mics
Controls
No
Circuitry
Solid-State
Performance
Frequency Response
50 Hz to 17 kHz
Maximum SPL
118 dB
Sensitivity
-28 dBV/Pa
Dynamic Range
96.2 dB
Equivalent Noise Level
21 dB (A-Weighted)
Connectivity
Analog Output Connector
1x XLR 3-Pin Male
Cable Length
12.1' / 3.7 m
Power
Power Sources
Phantom Power
Operating Voltage
11 to 52 V (Phantom Power)
Physical
Color
White
Mounting Thread Size
No Mount Included
Dimensions
H: 0.75 x W: 2.09 x L: 3.13" / H: 19.05 x W: 53.04 x L: 79.4 mm
Weight
4.44 oz / 126 g
Packaging Info
Package Weight
1.055 lb
Box Dimensions (LxWxH)
9.9 x 4.7 x 3.2"

Shure MX391 Reviews

Works as expected

By Andrew
Rated 4 out of 5
Date: 2025-09-08

Mic has good sound and easily replaced a Shure MX412 gooseneck mic. Four stars because it does transmit some surface noise (books or hands on the desk). I think that is expected behavior but more surface isolation should be possible. I do recommend it, and would purchase it again.

Excellent boundary mic

By kconnor9000
Rated 5 out of 5
Date: 2012-08-30

This is astoundingly good boundary mic for $. Much more solid, heavy, and elegant (both the mic and the inline preamp unit) than I expected. Pattern and noise are just as advertised. For most conference room applications, the room noise (computers, AC, etc.) is going to be much louder than the self-noise of these mics. I will probably pick up more. This version does NOT have a mute button, BTW. B&H delivery and pricing were top notch, per usual!

See any errors on this page?

Will this mic work with MXW1 as wireless ...

Will this mic work with MXW1 as wireless solution?
Asked by: TU
No, the Shure MX391 Microflex Cardioid Boundary Microphone is not compatible with the Shure MXW1 Hybrid Bodypack Transmitter.
Answered by: Manny C
Date published: 2024-03-10

Would one mic cover a 6 to 8 foot wide area with ...

Would one mic cover a 6 to 8 foot wide area with 2 to 6 people sitting at a witness table? Will be mixed with 9 other board member goose neck mics, the distance between the dias and the witness table is typically ten to 15 feet giver or take.
Asked by: greg
The abilities of the Shure MX391 Microflex Cardioid Boundary Microphone will likely be stretched when tasked with picking up voice from 6 to 8 feet, especially if some in this scenario are quiet speakers. For the best results in this specific situation, two MX391 would be ideal.
Answered by: Matt Z
Date published: 2022-07-23

question

does the mic hear vibrations on a floor such as dancers or people walking on a stage ?
Asked by: Charles
The Shure MX391 will pick up vibration from the surface it is placed on.
Answered by: Jeff P.
Date published: 2018-08-27

Will the mic work with MXW1 body pack for ...

Will the mic work with MXW1 body pack for wireless option?
Asked by: TU
No, the Shure MX391 Microflex Cardioid Boundary Microphone is not compatible with the Shure MXW1 Hybrid Bodypack Transmitter.
Answered by: Manny C
Date published: 2024-03-10

The white version has a 4 prong mini XLR, while ...

The white version has a 4 prong mini XLR, while the black version seems to be standard 3 prong xlr?
Asked by: Mark
The Shure MX391 Microflex Cardioid Boundary Microphone (White) comes with a TA4F connector. It includes a Shure preamplifier that is a TA4M connector on one side for the microphone to plug into, and an XLR on the other side to connect to a mixer, or an XLR mic input with phantom power.
Answered by: Elliot A
Date published: 2025-11-23

question

I'm trying to understand what it means to provide phantom power is for the shure 391o microphone?
Asked by: Anonymous
normally 48 v
Answered by: DIAMARELIS R.
Date published: 2018-08-27

Will 6 of these work in a meeting hall (25 people ...

Will 6 of these work in a meeting hall (25 people U table) without feedback?
Asked by: Diego
Feedback is typically caused by sound from speakers bleeding back into a microphone, which creates a feedback loop. The Shure MX391 is an omnidirectional boundary microphone, so it will be particularly susceptible to feedback as there is no axis of rejection. Caution should be used if the microphone is connected to speakers in the same area, and the speakers should be faced away from the microphone to avoid feedback.
Answered by: Calvin M
Date published: 2023-06-01

question

Does it come supplied with the cardioid cartridge?
Asked by: Kevin P.
Yes - this microphone does include the Cardioid transducer.
Answered by: Mark S.
Date published: 2018-08-27
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