Shure Beta 91A

Shure BETA 91A - Boundary Microphone for Bass Drum, Piano or Choir!

The Beta 91A is a boundary microphone for capturing bass drum and other low-frequency instruments as well as grand piano pickup. The condenser capsule and the preamp integrated into the housing deliver an excellent response with powerful, punchy low end. A switch lets you tailor the frequency response to avoid boominess.

How Does the Beta 91A Sound?

The Beta 91A boundary blends the sonic character of the classic SM91 — long favored for grand piano and piano pickup — with the full, punchy low end of the Beta 91, a favorite on bass drum and other low-frequency sources.

This smart combination produces a low-noise, half-cardioid microphone that easily handles extremely high sound pressure levels. A switchable filter attenuates the lower mids to prevent bass drum boom.

What's the Advantage of a Boundary Microphone?

The biggest advantage of a boundary mic is how quick and hassle-free positioning is. You simply place it inside the bass drum—no stands in the way.

Tip: Beta 91A in Combination with the Beta 52A
Audio engineers often pair the Beta 91A with the Beta 52A. Position the Beta 91A inside the bass drum for maximum attack and the Beta 52A outside the drum for maximum punch.

Also Suitable for Piano and Grand Piano

Using a boundary mic to capture a piano or grand is also common. The microphone is mounted inside on the lid.

What's the Difference to the Beta 91?

The Beta 91A integrates the preamp into the housing, which simplifies setup. It also offers a sound leaning toward the SM91 and includes a switch to cut the lower mids.

Excellent Response with Massive, Controlled Low End & Present Attack!