Benjamin B. Bauer

Uniphase Unidirectional Microphones

The unidirectional microphone is treated as a generalized transducer and network which are subjected to sound waves at two points in space. Network relationships are derived to produce unidirectional operation. These relationships are fulfilled in the “uniphase” structure which has a single transducer and a phase‐shifting network instead of the two transducers normally used in unidirectional microphones. Acoustical phase‐shifting networks applied to a diaphragm‐type piezoelectric microphone and to a moving coil dynamic microphone producing a cardioid‐type polar pattern are described.

Transformer Couplings for Equivalent Network Synthesis

It may be shown that regardless of the type of analogy chosen (“impedance” versus “mobility”), disconformity will be encountered in synthesizing the equivalent network of a mechano‐acoustic array. A method is described employing transformer couplings for getting around this difficulty. As a result, it becomes possible to construct equivalent circuits of mechanical arrays in a simple and straightforward manner by the method of impedance analogy. Similar benefits are achieved for the method of mobility analogy in the synthesis of equivalent circuits of acoustic arrays. Equivalent networks for certain mechano‐acoustic arrays which cannot be conventionally synthesized become feasible through this method.

A New System for Space Communication

In space communication, every means for transmitting maximum information should be provided. The new proposed system transmits the sense of direction as well as voice information between any number of suitably equipped persons. The transmission takes place with omnidirectional radiators. The reception is achieved by means of two limacon receptors, using “stereophonic‐binaural converters” to provide the desired space perspective.

New Stereophonic Projection Console

The simplicity and convenience afforded by a single instrument has proven to be an important factor in stereophonic sound reproduction in the home. A new stereophonic projection console has been developed, based upon practical directional properties of loudspeakers. The stereophonic projection console provides satisfactory separation of left and right sounds by reflection from the room boundaries. Measured performance characteristics and subjective evaluation of the system will be presented.

Acoustical Research Facilities at Columbia Broadcasting System Laboratories

The recently inaugurated Research Laboratories of the Columbia Broadcasting System, Inc., provide a new facility for research in communications. The Laboratories consist of three departments: Acoustics and Magnetics, Vacuum Tube and Solid State Physics, and Electronics Systems. The facilities of the Department on Acoustics and Magnetics comprise a wedge‐type Anechoic Chamber, a laboratory for Transducer Research, a laboratory for Recording Research, a psychoacoustic testing facility, facilities for research on magnetic recording, magnetic fields and transducers, fine magnetic particles, and instrumentation.

Uniphase Uni‐Directional Microphones

The uni‐directional microphone is treated as a generalized transducer and network which are subjected to sound waves at two points in space. Network relationships are derived to produce uni‐directional operation. These relationships are fulfilled in the “uniphase” structure which has a single transducer and a phase‐shifting network instead of the two transducers normally used in uni‐directional microphones. Acoustical phase‐shifting networks applied to a diaphragm‐type piezoelectric microphone and to a moving coil dynamic microphone producing a cardioid‐type polar pattern are described.