Sound and Its System

What is sound?

• basically a waveform of energy that is produced by some form of a mechanical vibration (ex: a tuning fork), and has a “frequency” determined by the origin of the sound (ex: a bass drum -low frequency sound and a cymbal - high frequency sound).

• A sound waveform has the same characteristics as that of an electrical waveform: are Wavelength (λ) – is the time period of one complete cycle in Seconds.Frequency (f) – is the number of wavelengths per second in Hertz. Velocity – is the speed of sound through a transmission medium in m/s-1.

• The sound’s frequency and wave shape are determined by the origin/ vibration (ex:_________________) that originally produced the sound

• The velocity is dependent upon the medium of transmission (air, water etc.) that carries the sound wave.

Notice the sound wave patterns below. What type of frequency and amplitude are used to create the pattern?

Transducer• are used in electronic communications systems to convert signals of various physical forms to electronic signals, and vice

versa. • In this example, the first transducer could be a microphone, and the second transducer could be a speaker. Label the

microphone and speaker.

Microphone

• an instrument for converting sound waves into electrical energy variations, which may then be amplified, transmitted, or recorded.

Reflect: Why is it bad to “thump” the top of the microphone?

Receiver

• Its primary purpose is to receive audio and video signals from a number of sources and process them to drive loudspeakers and a display.

Input/ Output/ Mixer

• Input- data received• Output- data delivered• Mixer- a person or machine that combines or balances sounds for a

recording, broadcast, or movie soundtrack

Equalizer

• adjusts the balance between frequency components within an electronic signal.

• Reflect: What circumstances are important to use equalization for a Sound Designer ?

Compressor

• Used to compress the sound levels to middle tones.• Ex: high frequencies to middle levels.

• What circumstances are important to use compression for a Sound Designer ?

Amplifier

• an amplifier modulates the output of the power supply to make the output signal stronger than the input signal.

• An audio power amplifier is usually used to amplify signals such as music or speech.

• Sound equipment that amplifies/boosts the low voltage, low current signal from a CD player, mixing desk etc. into a higher current signal suitable for driving speakers.

• As a general rule, each speaker in a sound system requires a separate amplifier. Each amplifier unit usually contains two amplifiers (for the two stereo components (left and right) of the sound signal), so with a single amplifier box, you can drive two speakers.

• What is a common amplifier in the theater?

Speakers

• a device which converts an electrical audio signal into a corresponding sound.• Most loudspeaker systems employ more than one driver, Individual drivers are

used to reproduce different frequency ranges. Subwoofers- very low frequencies3 Woofers -low frequencies1 Mid-range speakers- middle frequencies2Tweeters- high frequenciesSupertweeters -highest audible frequencies

• Label the three types of speakers on the diagram to the right.

Sources

• http://www.electronics-tutorials.ws/io/io_8.html