The AKG C391 B high-performance small-diaphragm condenser microphone is a pairing of the of the CK91 and the SE300 pre-amplifier. The polar pattern of the CK91 is cardioid, making it widely applicable in broadcast settings.
The C391 B also features the ability to quickly interchange its capsule with one of the other capsules of the Blue Line Series which all feature the Modulock coupling system, along with self-cleaning contacts for reliability and longevity. The C391 B provides a switchable bass roll-off/attenuator with three positions: flat, 75Hz and 10db attenuation.