EQUIPMENT FOR RADIO PRODUCTION

 

A radio station needs a number of equipments for producing and transmitting programmes.  

By definition, equipment are all the materials installed in the studio for the production of programmes, starting from furniture to digital equipment.

Some of the most common radio equipment are:

Transmitter

an antenna which beamed out  broadcast signals of a station. The transmitter has different range of coverage.  The short wave (SW) signals go very far others are medium wave (MW).

The microphones

A microphone can be regarded as an instrument which changes sound energy into electrical signals. Microphone as a device that converts or changes sound energy into electrical energy. This is a technology that amplifies and regulates the sound output in a programme. It converts the variation of sound pressure in a sound wave into corresponding electrical variation in an electric circuit.

There are basically two ways of distinguishing microphones.

(a) By the pickup pattern

(b) By the materials they are made with

(a) Pick Up Pattern: Microphone can be made so that they pick sound from one, two or all directions.

(i) Directionality: Pickup Pattern

 

• 
• A.        Omnidirectional
• B.        Bidirectional
• C.  Unidirectional (Cardioid)

 

1.    Cardioid

2.    Super Cardioid

3.    Hyper Cardioid

 

 

Omnidirectional Mics

 

• Equal output or sensitivity at all angles.
• It will pick up maximum amount of ambient sound.
• Should be placed close to the sound source to pick up a useable balance between direct sound and ambient sound.
• Cannot be aimed away from undesired sources such as PA speakers which may cause feedback!

 

 

 

 

Bidirectional Mics

 

• Maximum sensitivity at both 0 degrees (front) and 180 degrees (back).
• Least amount of output at 90 (and/or 270 degree) angles (sides).
• Used for picking up two opposing sound sources, such as a vocal duet.

 

 

 

 

Unidirectional Mics: Cardioid

• Maximum sensitivity at both 0 degrees (on-axis).
• Least sensitive at the rear (180 degrees off-axis)
• Effective coverage or pickup angle: about 130 degrees.
• Picks up about one-third as much ambient sound as an omni.
• Isolate the desired on-axis sound from both unwanted off-axis sound and from ambient noise.

 

 

Dynamic Microphones

Also called moving-coil mic.

• This classification includes ribbon mics (velocity mics).
• Simple construction, economical.
• Rugged, resistant to hand noise.
• Require no batteries or power supply.
• Standard equipment used by musical performers.
• Handle extremely high sound levels.

1.     Sound waves strike the diaphragm.

2.     Diaphragm vibrates in response.

3.     The voice coil, attached with the diaphragm, vibrates with it.

4.     The voice coil is surrounded by a magnetic field created by the magnet.

5.     The motion of the voice coil in this magnetic field generates the electrical signal.

 

 

Condenser Microphones

 

• Also called capacitor or electret condensor mic.
• More complex than dynamics, tend to be costly.
• Not as rugged as dynamic mics.
• Can be affected by extreme temperature and humidity.
• Require batteries or power supply.
• Standard equipment used by film production.
• Higher sensitivity, provides a smoother, more natural sound, particularly at higher frequency.

1.     Sound waves strike the diaphragm.

2.     Diaphragm vibrates in response, changing the space between itself and the metal or metal-coated-ceramic backplate.

3.     The variation of this spacing, due to the motion of the diaphragm relative to the backplate, produces the electrical signal.

 Electrical Impedance / Low-Z & High-Z Mics

• After a microphone changes acoustic energy into electric energy, the electric energy flows through a circuit as voltage.
• Whatever resistance that voltage encounters in the circuit is called impedance.
• Impedance is expressed in ohms.
• Less resistance means lower impedance.
• Low-impedance (low-Z): 600 ohms or less.

• High-impedance (high-Z): 10,000 ohms or higher.
• Professionals prefer low-impedance mics.
• Much less susceptible to hum and electric noise, such as static from motors and fluorescent lights.
• Can be connected to long cables (over 1000 feet, so says Shure) with negligible loss of sound quality.
• High-impedance mics usually begin to sound muffled due to a loss of high frequencies when used with a cable longer than 20 feet.

 

 
The Shotgun Microphone

A shotgun microphone, also known as a boom mic, is a long cylindrical microphone that is very directional. This means it won’t pick up as much background noise as most lavalier mics. The higher end shotgun microphones usually pick up more frequencies and sound better than comparable lav mics.