The Neumann KM 84 i, a classic small diaphragm FET condenser microphone, is the result of a visit to Norwegian State Television by Neumann engineers in the mid-1960s. NST wanted smaller, transistor-based microphones for a new studio but needed these microphones to run off of their central 48V DC power system rather than 12V T-Power. Neumann's engineers devised a plan for powering a microphone in this way and a major innovation, which we now know as phantom power, was born.

The KM 84 i uses the KK 64 capsule from the tube-amplified KM 64 microphone. This capsule produces a near-perfect cardioid pattern which maintains frequency response even 130-degrees off-axis and yields a very natural sound without comb-filtered artifacts due to bleed from other instruments.

The FET and transformer-output amplifier of the KM 84 i offers very high headroom, which makes the microphone widely used as a close microphone for drums, particularly snare drum. A -10dB pad is switchable on the body of the mic for recording especially hot signal sources.

As is the case with all Neumann products, the "i" designation is for microphones that shipped with an XLR output connector for export to the US. KM 84 (no i) is electrically the same, but has a din-type Tuchel connector for the output.