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CardioidShure Beta 91A

Cardioid Condenser Microphone

The Beta 91A is a boundary mic with a cardioid electret condenser capsule. It produces a half-cardioid response pattern, and is intended for use on piano and kick drums.

What are the differences between the Beta 91 and Beta 91A?

Both are half-cardioid boundary mics, with the same recommended applications. Both produce a half-cardioid response using the stock capsule.

The Beta 91A has about 6dB less self-noise (29.5 dBA vs. 35dBA), and higher sensitivity (3.8 mV/Pa vs. 1.1 mV/Pa).

The Beta 91A has a built-in XLR jack, whereas the original model required the use of an inline preamp (connected via mini-XLR cable).

Both mics use cardioid capsules from other mics in Shure’s product line — the Beta 91 used the RPM108 capsule (from the Beta 98) while the 91A uses the RPM98A/C (from the Beta 98A).

The Beta 91A introduces a “frequency contour” EQ switch, which cuts 7dB at 400Hz, “for a strong low frequency ‘punch’ with plenty of higher-frequency attack.”

Additional details are forthcoming.

Permalink: Shure Beta-91A

The mic was released in 2010.


Frequency Response - CardioidClick Graph to Compare!
Beta 91A Cardioid Frequency Response Chart
Pickup Patterns Pads & Filters
Cardioid (3.8 mV/Pa; 50 - 15,000 Hz)
  • Filter: -7dB @ 400Hz (peak) (Via Switch)
Capsule Dimensions Impedance SPL/Noise
Diameter n/a
146 Ohms (Low) Max SPL: 155 dB
Self-noise: 29.5 dB(A)
Weight Length Max Diameter Interface(s)
470g (16.58oz) 139mm (5.47'') n/a
  • 3-pin XLR male (1)
Power Specifications
  • Requires phantom power
  • Phantom voltage: 11–52v

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