Bauer’s system uses a single dynamic mic element, in which a voice coil is attached to a lightweight diaphragm. The voice coil sits within the field of a permanent magnet. The diaphragm and the voice coil are moved by sound waves, and an analogous electrical signal is produced within the voice coil wire. This technology reduced the size, weight, and cost as well as improved the performance of the company’s earlier microphones.
The first series of Unidyne mics, known as the 55 Series [see photo], featured a chrome-plated die-cast casing and a cardioid pattern that helped reduce unwanted background noise, which were brand-new features for a microphone, as well as a frequency response tailored to human speech.