Shure Beta 91A Half-Cardioid Boundary Condenser Microphone

Try this low-profile condenser mic inside a kick drum or piano, or place it in front of a cajon or marimba. The Beta 91A is perfect on low-frequency sources.

When it comes to recording kick drum, percussion, piano, vibes, or other low-frequency sound sources, the Shure Beta 91A will be your go-to microphone. Able to capture the critical attack and punch of any such instrument, the Beta 91A half-cardioid boundary condenser mic offers the right specs to get the job done right, in a design that sits well and looks great on stage and off.

Shure's Beta 91A sports an updated microphone capsule with an integrated preamplifier and handy XLR connection, with a versatile frequency response specifically tailored for bass frequency applications. Even at high SPLs, the mic will deliver superior sound quality wherever you need it -- it handles a max SPL of 151 dB!

Low-End Punch

Get bassy! Designed to capture the strength and punch of kick drums and traditional low-frequency applications, the Beta 91A is a half-cardioid boundary condenser microphone, offering the most gain-before-feedback and rejection of off-axis sound possible. In other words, the mic captures anything right in front of it while rejecting sounds from all sides except the front. When you place the Beta 91A in front of your kick drum, the kick comes through loud and clear, without being muddied by other ambient sounds from the room.

Customize Your Sound to Suit the Application

Its frequency response of 20 Hz to 20 kHz gives you a wide dynamic range to work with, even in high-SPL environments, while a convenient two-position Frequency Contour switch makes it easy to get read more the perfect level of attack and clarity for the application at hand. Flip the switch to the Flat Response setting for a more natural sound, or kick it into the Low-Mid scoop setting to get a stronger punch with additional high-frequency attack.

Designed for Easy Setup

In a slim, low-profile design, the Shure Beta 91A sports an integrated preamp and XLR connector, so you can set it and forget it on stage or in the studio. No external mounting or accessories or required -- just plug it in and enjoy nothing but high-quality sound. When not in use, keep the mic in its included zippered pouch.


- Half-cardioid boundary electret condenser microphone
- Ideal for capturing kick drums and other low-frequency instruments
- Uniform half-cardioid polar pattern (cardioid in hemisphere above mounting surface) provides max gain-before-feedback and rejection of off-axis sound
- Frequency response: 20 Hz to 20 kHz
- Low-profile design minimizes stage clutter
- Integrated preamplifier and XLR connector for faster setup
- Frequency response tailored for kick-drum/low-frequency applications with a wide dynamic range for use in high-SPL environments
- 2-Position Frequency Contour Switch lets you customize your level of attack and clarity
- Flat Response setting offers a natural sound in most applications
- "Low-Mid scoop" setting provides a strong low-frequency "punch" with plenty of higher frequency attack
- Requires no external mounting or accessories
- For easy setup, it has a 3-pin, male, balanced XLR connector
- Ships with a zippered pouch for storage and transport
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Type: Electret Condenser

Frequency Response: 20 to 20,000 Hz

Polar Pattern: Half-cardioid (cardioid in hemisphere above mounting surface)

Impedance: 146 Ohms

Sensitivity (at 1 kHz, open circuit voltage):
- -48.5 dBV/Pa (3.8mV)
- 1 Pascal=94 dB SPL

Maximum SPL (1 kHz at 1% THD): 1000 Ohm load: 151 dB, 2500 Ohm load: 155 dB

Signal-to-Noise Ratio (referenced at 94 dB SPL at 1 kHz):
- 64 dB
- S/N ratio is difference between 94 dB SPL and equivalent SPL of self noise, A-weighted

Dynamic Range (at 1 kHz):
- 1000 Ohm load: 121.5 dB
- 2500 Ohm load: 125.5 dB

Common Mode Rejection (20 Hz to 20 kHz): > 55 dB

Clipping Level (20Hz-20 kHz at 1% THD):
- 1000 Ohm load: 7.50 dBV, 2500 Ohm load: 12.5 dBV
- THD of microphone preamplifier when applied input signal is equivalent to cartridge output at specified SPL

Self Noise (typical, equivalent SPL, A-weighted): 29.5 dB SPL-A

Polarity: Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3

Weight: 470 g (16.6 oz.)

Frequency Contour Switch: 7 dB of attenuation centered at 400 kHz

Connector: Three-pin professional audio (XLR), male, balanced

Power Requirements: 11-52 Vdc phantom power, 5.6 mA
Dimensions and Weight in Packaging
Base Item
Shipping Weight: 1.75 lbs
Shipping Dimensions: 10 x 5 x 4 in
Manufacturer Part Number (MPN): SHU BETA91A

For support or warranty questions, please contact the manufacturer:
Phone: 800-516-2525

Shure Beta 91A Boundary Microphone

The Shure Beta 91A is designed for use with kick drums, as well as other traditional low-frequency applications including piano. Featuring an updated microphone capsule, integrated preamplifier, and XLR connection, the Shure Beta 91A offers a strong low-frequency response and is specifically tailored for bass frequency applications. The Shure Beta 91A combines superior attack and punch for studio-quality sound, even at extremely high sound pressure levels (SPL).


- Uniform half-cardioid polar pattern for maximum gain-before-feedback and rejection of off-axis sound
- Precision-engineered low-profile design features integrated preamplifier and XLR connector to maximize setup efficiency while minimizing stage clutter
- Frequency response tailored for kick drum/low frequency applications with a wide dynamic range for use in high SPL environments
- Two-position contour switch to maximize attack and clarity depending on application: select the flat response setting for natural sound in most applications or the "low-mid scoop" setting for a strong low frequency "punch" with plenty of higher frequency attack
- Requires no external mounting or accessories for ease of use and storage
- Furnished with zipper pouch

Reviewers gave this product an overall rating of 5 out of 5 stars. (4 ratings)
Submitted November 26, 2012 by Jay H
"Excellent mic for cajon"
Overall: 5 out of 5 stars
(see rating details)
Verified Customer zZounds has verified that this reviewer made a purchase from us.
I bought this mic to use in my Meinl Siam Oak String Cajon. This mic sounds incredible! The cajon sounds amazing through the PA. I tried recording using the Shure Beta 91A and it sounds great. I like it better than the sound that I was getting with my two mics placed outside of the cajon. If you are looking for a cajon mic, this is hard to beat. It's built well and heavy so it stays in place. I could not be happier with the sound quality of this mic. I am running the mic through a BEHRINGER PS400 MICROPOWER PWR SUPPLY/48v Phantom Power.My PA is a Behringer PMP2000 with JBL JRX115 speakers.I am using Vator Cajon Brushes which I recently discovered.
Musical Background:
I have been playing music for 30+ years. I play drums/percussion and guiatr in a band.
Musical Style:
Acoustic folk, rock, blues, country
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