From the AKG Blue Line series of modular microphone capsules, the AKG CK91 is a cardioid capsule with signal characteristics that allow the microphone to be used in a variety of applications. The miniature capsule features a flat wide frequency response of 20Hz to 20kHz allowing smooth accurate signal reproduction without coloration. The cardioid polar pattern is effective in eliminating noise and ambiance at the off-axis sections of the capsule. The result minimizes feed-back and allows the CK91 to be used to spot capture instruments and vocals for sound reinforcement and crucial recording. The CK91 is powered with the AKG SE-300B power supply.