Transcript chap14 - Cerritos College

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Chapter 14
Recording and Editing
Sound
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Recording and Editing Sound
• In this Chapter, you will learn:
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How sound capability enhances your PC
How your PC records, stores and plays digital sound
How speech synthesis works
What you should know about MIDI
How to add sound clips to presentations and Web pages
How to work with digitized sound
About Sound devices
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How sound capability enhances XP
your PC
• Your PC contains a sound card which is used to
generate sound through speakers or headphones.
• PC Sound is used in many ways:
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Beeps to alert you to e-mail
Sounds to tell you an action cannot be done
Music that can be downloaded from the Web
Listening to on-line college courses
Sound affects for games
Audible screens for visually impaired people
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How sound capability enhances XP
your PC
• Computers work with two types of sound:
– Digitized sound records real music, sound effects for
speech. Digitized sound has been converted into
electronic signals that can be stored and manipulated.
– Synthesized sound is not recorded, but generated from
a machine such as a computer.
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How a PC records, stores and
plays digital sound
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• Digital sound is created using a microphone,
sound card and software and saved in formats such
as .wav, .au and .voc.
• Characteristics of sound are amplitude (volume)
and frequency (high or low note).
• Samples of the wave are stored in the sound file.
• The more samples in a file, the better the sound,
but the larger the file – measured in KHz.
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How a PC records, stores and
plays digital sound
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Sampling a sound wave
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How speech synthesis works
• Computers can create sounds called speech
synthesis resembling spoken words.
• Most synthesizers use basic sounds (phonemes)
strung together to form words.
• Synthesizers also work from text-to-speech,
“reading” the text.
• Synthesized speech can also be used in getting
email messages over your voice mail system.
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How speech synthesis works
Using speech synthesizing software
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What you should know
about MIDI
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• MIDI is musical instrument digital interface and
specifies a standard way to store music on
computers and other electronic devices.
• MIDI files contain MIDI messages – akin to a
player piano roll.
• MIDI works with instrumental music, but not
vocal.
• MIDI files require much less storage space than
digital files.
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What you should know
about MIDI
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• MIDI music is created by:
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Composing it on the computer
Entering the notes on a musical staff
Assigning the notes to different instruments
Adding harmony
Adding percussion
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What you should know
about MIDI
Using MIDI software
You can write
music note by
note, or play it
on a MIDI
keyboard
You can
assign an
instrument
and MIDI
track to each
musical part
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Adding sound clips to
presentations and Web pages
• A sound clip must first be a digitized sound file or
a MIDI file.
• You can compose one or find sound clip files on
the Web or to buy.
• Presentation software packages have specific
sound formats they will accept, but WAVE and
MIDI are standard Web formats.
• Other sound formats may require special plug-ins
for Web site visitors to be able to use.
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Adding sound clips to
presentations and Web pages
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Adding sound to a Web site using Word
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Hardware – Sound devices
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• Most modern PCs contain a sound system with:
– speakers and/or headphones. Your speaker quality
should match your sound card quality.
– a sound card, which is a circuit board on the PCs
motherboard.
• Upgrading the sound card to a higher frequency response (Hz)
produces better quality sound.
• FM synthesis and Wavetable synthesis are two sound card
techniques available
• Wavetable synthesis is newer and produces better sound
– a microphone.
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Hardware – Sound devices
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A diagram of a typical sound system
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Hardware – Sound devices
• MIDI instruments can be added to your PC sound
system.
• MIDI instruments electronically synthesis music.
• The most popular instrument is a MIDI keyboard.
• These MIDI keyboards approximate piano
keyboards.
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Hardware – Sound devices
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A MIDI keyboard
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Working with digitized sound
Using the Windows Sound Recorder program
The sound wave
playing or
recording
Slider shows status
Rewind
Record
Fast
Forward
Stop
Play
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What do you think?
RIAA vs. Rio
1.
When you purchase a music CD, do you believe that you
should have the right to convert it into any format (such as
cassette tape or MP3) for your own use?
2.
Do you believe that Rio and MP3 would be more attractive
to music pirates than cassette tape?
3.
Do you think that it should be illegal to sell an MP3 device,
such as Rio?
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Chapter Summary
• You should now know:
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What sound capability your PC has
What digital sound is.
How speech synthesis works
What MIDI is
How to add sound clips to presentations and the Web
How to work with digitized sound
About the basic types of sound devices
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