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Chapter 15 Recording and Editing Sound

Chapter 15 Recording and Editing Sound

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Chapter 15 Recording and Editing Sound

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  1. Chapter 15Recording and Editing Sound

  2. Getting Started • In this Chapter, you will learn: • 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 • What is ripping • About Hardware: Sound devices Practical PC 5th Edition Chapter 15

  3. How does sound capability enhance by PC • Sound adds a new dimension to your PC • Beeps and sounds provide feedback as you use your PC • Music lovers can listen to sample tracks • Children can listen to stories • Visually impaired individuals can have the screen contents read to them • Computers work with two general categories of sound • Digitized sound is a recording of real sound converted into electronic signals • Synthesized sound has not been recorded from a live source, but instead has been generated by a machine • Each sound category has unique characteristics and applications Practical PC 5th Edition Chapter 15

  4. How does my PC record, store, and play digital sound? • To digitally capture sound, you need a microphone and sound software • A sound wave provides information about a sound • Height of wave indicates volume, called amplitude • Time between wave peaks indicates the sound’s frequency • To digitally store a sound wave, your PC periodically records a sample of the wave’s amplitude as a binary number • Sampling rates are measured in kHz (kilohertz), where 1 kHz is 1,000 samples per second • For human voice, 11 kHz works fairly well. For music, 22 kHz to 44 kHz is required • Digital sound files that have not been compressed are big • WAV is a popular uncompressed audio file format Practical PC 5th Edition Chapter 15

  5. How does speech synthesis work? • Machines produce sound that resembles the spoken word through speech synthesis • Most speech synthesizers string together basic sounds called phonemes • Speech synthesizer typically includes text-to-speech software and synthesizing hardware • Text-to-speech software examines the text on a PC and breaks it down into a series of sounds that can be output • Synthesizing software consists of electronic circuitry that can generate speech or musical sounds • Unlike digitized speech, synthesized speech can theoretically produce any words or phrases Practical PC 5th Edition Chapter 15

  6. What should I know about MIDI? • MIDI (musical instrumental digital interface) specifies a standard way to store music data • MIDI files contain instructions, called MIDI messages, for synthesizing music based on pitch, volume, and duration of each note made by each instrument • MIDI is suitable for instrumental music, but not for vocals • MIDI’s advantage lies in its ability to store lengthy musical sequences in a small file • Use sequencer software to capture the musical themes from a MIDI instrument or enter the notes on a musical staff • Edit your composition by assigning notes to instruments, adding harmony, and inserting percussion Practical PC 5th Edition Chapter 15

  7. What should I know about MIDI? Composing MIDI Music Practical PC 5th Edition Chapter 15

  8. What is ripping? • Ripping is slang for importing tracks from a CD or DVD to your computer’s hard disk • Technical term for ripping is digital audio extraction • Ripping is handy when moving files between PCs and devices • Music file formats • CD-DA (Compact Disc Digital Audio) format for music on CDs • Music from CDs is usually compressed into: MP3, AAC (Advanced Audio Coding), and WMA (Windows Media Audio) • Many software tools for ripping CD tracks are available • In the U.S., ripping music for personal use is controversial since it is done without the artist’s permission Practical PC 5th Edition Chapter 15

  9. What is ripping? Ripping music to a CD using iTunes software Practical PC 5th Edition Chapter 15

  10. Hardware: Sound devices • Most PCs today include a basic audio system with a sound card, speakers, and possibly a microphone • A sound card is a circuit board that typically plugs into an expansion slot on your PC • Provides connectors for a microphone, speakers or headphones • Provides a joystick port that doubles as a port for MIDI instruments • Basic sound card is adequate for playing games, business software, and Web browsing Practical PC 5th Edition Chapter 15

  11. Hardware: Sound devices The sound card is the basic building block of your PC’s audio system Practical PC 5th Edition Chapter 15

  12. Hardware: Sound devices • Digitized sound • Sound card reproduces the digital samples in the sound file • Sound quality depends on several factors, the most basic being frequency response. Frequency response is the range of notes it can produce • MIDI music • Sound card receives messages from a MIDI file • Wavetable synthesis generates music by patching together a set of sounds (patch set) prerecorded as individual notes from actual instruments • 256-voice wavetable produces better quality sound than a 64-voice wavetable Practical PC 5th Edition Chapter 15

  13. Hardware: Sound devices • Sound card outputs sound to speakers or headphones • New technologies include surround sound, 3-D sound, and environmental sound • Speakers • Speakers cannot improve sound quality, but cheap speakers can degrade it • Your speaker quality level should match the quality level of your sound card • Most speaker systems include two speaker units • Higher end systems may also include a subwoofer to produce enhanced bass sound Practical PC 5th Edition Chapter 15

  14. Hardware: Sound devices • Microphones • Sound card receives input from a microphone or MIDI device • For better sound quality choose a good-quality “mic” • Portable audio player • Pocket-sized, battery-powered device that stores digital music • Transfer music from your PC or buy songs online • Connect to headphones or stereo system • Supports a variety of compressed audio formats • Some can also play videos and e-books Practical PC 5th Edition Chapter 15

  15. Can I copy it? • What do you think? • When you purchase a music CD, do you believe that you have the right to convert it into any format (such as cassette tape or MP3) for your own use? • Do you think the Digital Millennium Copyright Act should be revised to allow people to circumvent DRM for music that has been purchased legitimately? • Have you ever been prevented from copying music by some type of DRM technology? Practical PC 5th Edition Chapter 15

  16. Chapter Summary • You should now : • Know how sound capability enhances your PC • Know how your PC records, stores, and plays digital sound • Understand how speech synthesis works • Know about MIDI • Understand ripping • Understand sound devices Practical PC 5th Edition Chapter 15