TELEVISION MICROPHONES

LEARNING 0BJECTIVE: Recognize the types of microphones used in television productions.

Sound plays a vital role in the television communication process. Most human intelligence is transmitted through sound; therefore, good quality sound is an important part of television. However, good quality sound is rather difficult to achieve at times because sound sources may be in motion, talent may speak to the camera and not into the microphone and microphones must sometimes be hidden from the view of the camera. To help solve these audio problems, you should have a basic understanding of television microphones.

Microphones are usually classified according to the way they pick up sound, also known as their polar pattern. Sound in physical terms is the vibration of air particles or small fluctuations of air pressure that spread like waves from a source of sound. Human ears respond to this change in pressure within a sound field. Similar to a human ear, microphones respond to the change in air pressure created by sound waves and convert the fluctuations of pressure into electrical current.

Figure 14-19. - Microphone polar patterns.

POLAR PATTERNS

The pickup, or polar pattern, of a microphone is the shape of the area around it where it picks up sounds with maximum fidelity and volume. Nearly all microphones can pick up sounds from areas outside the ideal pattern, but their quality is not as good. For best results, the sound source should be within the pickup pattern, generating enough volume to allow the audio switcher to keep the volume control pot at a minimal level.

Microphones are classified according to the following three basic polar patterns: l Unidirectional l Omnidirectional l Bidirectional

Unidirectional

The unidirectional microphone picks up sound from only one direction. Because of this characteristic, the unidirectional microphone is used most frequently for television work. It is used by aiming it in the direction of the sound source being recorded. One advantage to the unidirectional microphone is its ability to reject unwanted sounds at the side and rear of the direction the microphone is aimed.

Omnidirectional

The omnidirectional (or nondirectional) microphone is live in all directions. This type of microphone has sensitivity characteristics in which sound is picked up in a 360-degree radius. The use of this microphone in television production is limited; however, in certain situations, you may use it to create a specific sound presence. One example is recording crowd noise for a sports production.

Bidirectional

As the name implies, the bidirectional microphone picks up sound in two directions. This type of microphone is used primarily in the broadcast or recording studio. It is also used for critical sound reinforcement applications in which front and rear

Figure 14-20. - Giraffe boom.

pickup and greatly reduced side pickup are desirable. The bidirectional microphone is ideal for such applications as "across the table" interviews or dialogue recording under studio conditions.

The polar patterns of all three microphones are shown in figure 14-19.