kuliah 10 audio

8/8/2019 Kuliah 10 Audio

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What is Sound?

Sound is the brains interpretation o electricimpulses being sent by the inner ear through

nervous system.


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What is Sound?

In terms o the physical event, sound is a ser

o vibrations that travel through some medi


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Dimension of Sound

Amplitude:

the amount by which the airpressure changes rom the

normal background air

pressure, whether positive or

negative.


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Dimension of Sound

The scientic term or how many peaks (ortroughs) o a sound pass a given point within a

given time is requency.

Standard measurement o requency: Hertz (Hz), or cycles persecond; the number o complete periods (one upward crest

and one downward trough) that occur each second


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Dimension of Sound


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Sound in a Multimedia Project

Content sound provides inormation to audiences.For examples narration, dialogue, voice-overs, music

Ambient sound consists o an array o background and sound e

For examples message reinorcement, background music, soun

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Digital Audio


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Sampling

Sound sampling transers a continuous sound wave into discreteWhen sampling a sound, the computer processes snapshots o th

The requency o these snapshots is called the sampling rate. The

typically rom 5000-90,000 samples per second.

i h


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Bit Depth

The bit depth determines the amount o detail that can be recordincoming level o the signal the y-axis o waveorm diagrams.

8-bit and 12-bit converters were used in many early digital audio

today 16-bit and 24-bit converters are the most common.

Th S d Q li f Di i i d S d


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The Sound Quality of Digitized Sound

Di i l A di Fil F (U d


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Digital Audio File Format (Uncompressed

PC (Windows) : WAV

Mac : AIFF

CD Audio : CDA

C i


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Compression

Compression in computer terms means reducin

physical size o data such that it occupies less st

space and memory.

S h f A di C i


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Schemes of Audio Compression

ADPCM (Adaptive Diferential Pulse Code Modu

MPEG (Motion Picture Experts Group)

ADPCM


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ADPCM

Using this technique one can achieve about 40-80% comp

Examples ile ormat:

Windows PCM (*.wav), Microsot ADPCM (*.wav), PCM raw

(*.pcm, *.raw)

MPEG


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MPEG

MPEG Layer 1 compression ratio is 1:4 (*.mpg)

MPEG Layer 2 compression ratio is 1:6-1:8 (*.m

MPEG Layer 3 compression ratio is 1:10-1:12 (*

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Software

Adobe AuditionGarage Band

Sound Forge

Audacity


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Terima Kasih

cokyauziali.wordpress.com

kuliah 10 audio

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