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, Beta 91A offers a strong low-frequency response and is specifically tailored for bass frequency applications. The Beta 91A combines superior attack and punch for studio-quality sound, even at extremely high sound pressure levels (SPL).Shure Beta 91A is an electret condenser utilizing a half cardioid which is very characteristic of a proximity or boundary mic. It is designed for use low profile applications like inside kick drums and grand pianos. It can handle SPL's of up to 155dB and respond to the full frequency spectrum (20Hz – 20kHz). The built-in contour switch gives the mic more low-end punch. Makes a great duo with a Beta52A on a kick drum using the 52 outside and the Shure Beta 91A inside. Used as an inner kick drum mic by too many bands to list here.