What Shure has to say:
The Shure BETA 91t is a high performance condenser microphone with a tailored frequency response designed specifically for kick drums and other instruments. It provides superb attack and “punch,” and delivers studio quality sound, with minimal distortion even at extremely high sound pressure levels.
The BETA 91 features a half-cardioid pattern (cardioid in the hemisphere above the mounting surface) throughout its fre- quency range to insure high gain before feedback and excel- lent rejection of unwanted sound.
Frequency response shaped specifically for kick drums and other instruments
Wide dynamic range for use in high SPL environments
Low-profile design requires no external mounting hardware
Detachable cable for easy storage
Legendary Shure quality, ruggedness, and reliability GENERAL RULES FOR MICROPHONE USE
Aim the side of the microphone marked “Shure” toward the desired sound source and away from unwanted sources. This may not be obvious or intuitive, since car- dioid microphones such as the BETA 91 have narrow pickup patterns.
Placethemicrophoneascloseaspracticaltothedesired sound source (refer to the table below) to maximize sig- nal-to-noise ratio.
Use only one microphone to pick up a single sound source.
Use the fewest number of microphones as practical.
Keep multiple microphones separated by a distance equal to at least 3 times the distance to the nearest sound source.
APPLICATIONS AND PLACEMENT
The most common BETA 91 application and placement technique is listed in the following table. Keep in mind that mi- crophone technique is largely a matter of personal taste–there is no one “correct” microphone position.
A 4.6 m (15 ft) heavy-duty cable is supplied for connecting the BETA 91 microphone to the preamplifier. It may be desirable for the components to be located a greater distance apart. Up to 23 m (75 ft) of additional cable can be used between the BETA 91 microphone and the preamplifier without signal loss.
Cardioid condenser (electret bias)
20 to 20,000 Hz (see Figure 1)
(measured at 304.8 mm [1 ft] from a spherical sound source, free field conditions)