Neumann KK 133 NX Omnidirectional diffuse-field capsule head in woodbox, nextel. Compatible with KM A (analog) or KM D (digital) output stages.

The KK 133 is a diffuse-field equalized pressure transducer with a free-field treble boost (4-5 dB at 12 kHz). Based on the technical design concept of the legendary Neumann M 50 microphone and its successor, the M 150, its ultra thin diaphragm is made of titanium and is spaced only a few microns from the backplate, also made of titanium. The KK 133 capsule attains an incredibly fast transient response with unprecedented accuracy. Its detachable sound diffraction sphere creates an earlier and gentler increase in sound pressure for mid to high frequencies. Directivity, thus, increases in the upper frequencies, as with a cardioid capsule, yet as a pressure transducer the KK 133's bass transmission is linear down to the lowest frequencies, with no proximity effect.