Shure Beta 91A Boundary Microphone
The Shure Beta 91A Boundary Microphone provides a strong low-end response and maximum gain-before-feedback due to its half-cardioid polar pattern. It features a two-position contour switch to maximize attack and clarity and a low-profile design.
The Shure Beta 91A Boundary Microphone 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).
Shure Beta 91A Boundary Microphone Features
- 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
Shure Beta 91A Boundary Microphone Specifications
- Type: Condenser (Externally Biased)
- Frequency Response: 20 to 20,000 Hz
- Polar Pattern: Half-Cardioid (Cardioid in Hemisphere Above Mounting Surface)
- Impedance: 146 O
- Sensitivity (at 1 kHz, Open Circuit Voltage): -48.5 dBV/Pa (3.8 mV) 1 Pascal=94 dB SPL
- Maximum SPL (1 kHz at 1% THD):
- 1000 O Load: 151 dB
- 2500 O Load: 155 dB
- Signal-to-Noise Ratio (Referenced at 94 dB SPL at 1 kHz): 85.5 dB
- Dynamic Range (at 1 kHz):
- 1000 O Load: 121.5 dB
- 2500 O Load: 125.5 dB
- Common Mode Rejection (20 Hz to 20 kHz): > 55 dB
- Clipping Level (20Hz-20 kHz at 1% THD):
- 1000 O Load: 7.50 dBV
- 2500 O Load: 12.5 dBV
- 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 Net: 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 (IEC-61938), 5.6 mA
Shure Beta 91A Boundary Microphone Includes
- 1 x Shure Beta 91A Boundary Microphone
- 1 x Shure 95A2314 Storage Bag
- 1 Year Warranty
Shure Beta 91A Boundary Microphone Downloads
- Shure Beta 91A Boundary Microphone User Guide (PDF)
- Shure Beta 91A Boundary Microphone Spec Sheet (PDF)
1 Review Hide Reviews Show Reviews
I brought this mic for a very specific purpose, to capture bass drum attack for aggressive/rowdy music, primarily to save from over-equalizing the primary bass drum microphone - for this purpose it is perfect.
The 1-6" placement recommended didn't work for me, rather - placing the mic inside the bass drum around 1" from the resonant head pointing at the batter did, this had the capsule placed around 1/3rd of the way inside the drum head and gave the mic a reasonably balanced tone (otherwise it was unnaturally subby).
Seems to me to be a very specific use mic, as-in 1-trick pony, hence only 4x stars instead of 5.
As an aside I'm a total fanboy of Shure mics, particularly the KSM series, so, take this review with a pinch of salt.