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Sound

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Select the appropriate sound card for a given scenario. Install a sound card ... or MP3. Playing Sounds ... use the standard WAV, MP3, or MIDI file formats ... – PowerPoint PPT presentation

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Title: Sound


1
Sound
  • Chapter 13

2
Overview
  • In this chapter, you will learn to
  • Describe how sound works in a PC
  • Select the appropriate sound card for a given
    scenario
  • Install a sound card in a Windows system
  • Troubleshoot problems that might arise with sound
    cards and speakers

3
How Sound Works in a PC
4
Sound-Capture Basics
  • Sound can be visualized as a constantly changing
    series of frequencies, which can be graphed as a
    waveform
  • The PC turns the waveform into a digital file by
    taking samples at regular intervals

5
Sound-Capture Basics
  • The quality of recorded sound is
    based on the number of bits used
    for each sample, and how
    often the sound is sampled
  • Waveforms are commonly sampled
    with either 8 or 16 bits per sample
  • 8-bit stores 28 or 256 different frequencies
  • 16-bit stores 216 or 65,536 different frequencies

6
Sound-Capture Basics
  • The sampling rate for a digital waveform is
    measured in thousands of time per second or
    kilohertz (KHz)
  • The more samples per second, the higher the
    quality of recorded sound
  • Waveforms are sampled in individual tracks
  • Monaural in one track
  • Stereo in two tracks

7
Sound-Capture Basics
  • Waveforms are recorded at different
  • Bit depths 8-bit or 16-bit
  • Sample rates 11 to 44 KHZ
  • Numbers of tracks monaural, stereo or more
  • The WAV format for Windows provides a maximum of
    16-bit sampling at 44 KHz on two tracks

8
Recorded Sound Formats
  • Pulse code modulation (PCM)
  • Better known as the WAV format
  • Large files
  • 10 MB per minute for 16-bit stereo sampled at 44
    KHz
  • Compressor/decompressor (CODEC) programs
  • Algorithms developed to compress sound files
  • MPEG-1 Layer 3 codec or MP3

9
Playing Sounds
  • Every sound card can play WAV files using a sound
    player software
  • Media Player comes with Windows
  • Many other good sound players are available

10
MIDI
  • Musical Instrument Digital Interface (MIDI)
  • Second most popular type of sound on a PC
  • Designed to enable musicians to create, store,
    and play a broad cross section of instruments,
    including instruments invented on synthesizers
  • Sound card that has built-in recordings of real
    musical instruments
  • More expensive sound cards have larger numbers of
    instruments and better quality recordings

11
MIDI
  • A MIDI file contains a series of commands that
    describe
  • What note to play
  • How long to play it
  • Which instruments to use
  • Each instrument is called a voice

12
MIDI
  • The number of different instruments a sound card
    can play simultaneously is called its polyphony
  • Most sound cards today have at least 32-voice
    polyphony
  • Sound cards use one of the two methods for
    storing musical instruments
  • FM synthesis
  • Wavetable synthesis (higher quality)
  • Great for storing music but cant save a human
    voice or an explosion

13
Video
  • Video files have sound built into them
  • Most common video formats
  • Audio Video Interleaves (AVI)
  • Moving Pictures Experts Group (MPEG)
  • QuickTime (MOV)
  • Advanced Streaming Format (ASF)
  • RealMedia (RM)

14
Applications
  • Many applications play sounds
  • Most use the standard WAV, MP3, or MIDI file
    formats

15
Streaming Media
  • Broadcast of data that is played on your computer
    and immediately discarded
  • Internet radio stations
  • Most popular players are
  • Windows Media Player
  • Winamp

16
Getting the Right Sound Card
17
Sound Cards
  • A sound card takes waveforms or MIDI files as
    input and generates analog signals to speakers or
    to a recording device
  • A sound card has two complete sets of components
    to support both waveform and MIDI

18
Functions of a Sound Card
  • Record and play waveform files
  • Record and play MIDI files
  • Enable recording from a microphone or auxiliary
    input (CD player, vinyl record, tape)
  • Assist in playing CD-ROMs from the CD drive

19
Processor Capabilities
  • The sound processor handles the communication
    among the application, operating system, and CPU
  • Low-end sound cards let your CPU do most of the
    work
  • Better sound cards do most of the processing
    which accelerates the sound process

20
Speakers
  • The speaker connection enables the sounds to be
    output to speakers
  • The classic PC sound card/speaker configuration
    supports two speakers in a stereo configuration
  • Speakers connect to the system through a single
    mini audio connector
  • The sound card has a minimal amount of
    amplification and therefore speakers have
    built-in amplifiers powered by batteries or an AC
    adapter

21
Jacks
  • Line In and Line Out converters enable the sound
    card to send and receive input and output from
    devices other than the speaker or microphone
  • The Line In connector runs to a Line Out or Aux
    connector on the back of a stereo receiving
    system
  • The Line Out is also often connected to a stereo
    system
  • Rear Out connects to rear speakers for surround
    sound
  • Analog/Digital Out for external digital
    connections
  • Microphone Joystick

22
Sound Card Connections
  • Main stereo speaker is blue
  • Line out connector is green
  • Microphone connector is pink

23
Recording Quality
  • Based on the signal-to-noise ratio
  • Low and mid range cards 30 to 50 decibels
  • High-end range 96 to100 decibels

24
Audio Cables
  • To play audio CDs through your sound card
    requires a cable from your CD drive to the sound
    card
  • Most CD media drives come with an MPC2 audio
    cable for this purpose

25
Speaker Standards
  • Stereo
  • Left and right
  • 2.1 systems
  • Pair of speakers called satellites and
    a subwoofer

26
Speaker Standards
  • 3D sound
  • Surround sound designed for music and movies that
    surrounds the listener with sound
  • 3D sound on the PC
  • True 3-D sound (used in 3-D games) that enables
    programmers to make sounds directional

27
Surround Sound
  • Uses multiple soundtracks with each one dedicated
    to a different speaker
  • There are three predominant types
  • Dolby Surround or Dolby Pro Logic
  • Uses four speakers
  • Dolby Digital
  • Up to six separate channels with its own speaker
  • .1 describes the subwoofer (the low sounds you
    feel more than you hear)
  • Digital Theatre Systems (DTS)
  • Uses less compression than Dolby Digital and is a
    direct competitor

28
DirectX
  • DirectX provides applications, primarily games,
    with virtually complete direct access to the
    hardware
  • Use the proper version of DirectX for your
    application or game to work
  • The DirectX diagnostic tool can be used to
    determine the version of DirectX
  • Access the DirectX Diagnostic Tool from the Tools
    ? Windows menu in Computer Management in Windows
    2000

29
Installing a Sound Card in a Windows System
30
Physical Installation
  • Installs like any other PCI card
  • Connect the CD audio cable from your CD or DVD to
    the CD Audio port on the sound card
  • Usually there are three ports on the card for a
    CD drive, DVD drive, or modem
  • Connect the external wires
  • Stereo or 2.1 speaker systems usually have just
    one jack labeled speaker
  • Surround speakers have either one Sony/Phillips
    digital interface (SPDIF) connector to the
    subwoofer or separate wires for the front two
    speakers (Speaker 1), back two speakers (Speaker
    2), and the subwoofer or center channel

31
Multiple Audio Connectors
32
Device Drivers
  • Sound cards, due to their multiple functions of
    waveform, MIDI, and possibly CD-ROM, have
    complicated device drivers
  • Dont think of it as the sound card driver.
    Instead think of the device driver as 3 or more
    different device drivers waveform driver, MIDI
    driver, CD-ROM controller driver, and so on
  • Most sound cards come with an easy installation
    program

33
Device Manager
  • The Device manager displays the several functions
    of a sound card as separate devices.
  • OPL3 is a MIDI device

34
Configuration Applications
  • Most or all of your sound card configuration can
    be done with the Sounds and Audio Devices applet
    in Windows XPs Control Panel
  • Or Sounds and Multimedia in Windows 2000 and Me
  • Or the two applets, Sounds and Multimedia, in
    Windows NT and Windows 9x

35
Configuration Applications
36
Troubleshooting Sound
37
Hardware Problems
  • These types of problems are easy to diagnose and
    are generally due to a faulty physical
    connection, volume control, etc.
  • Some older sound cards have a volume control
    wheel on the card itself, which should be
    adjusted for audible output
  • Crackling sounds coming from the speaker or in
    microphone recordings usually indicate bad wires

38
Drivers
  • The correct device driver needs to be configured
    for the proper functioning of a sound card
  • Ensure that the latest device drivers are
    installed
  • Check the manufacturers web site for updates
  • Check Device Manager

39
Speakers
  • Make sure they are on and getting power
  • Make sure they are plugged in right
  • Check the volume control settings

40
Application
  • An application that uses sound has its own set of
    configuration issues
  • Some applications, such as games, may require
    advanced sound features
  • See if you can get sound in Control Panel. If you
    can, then the problem lies in the application.

41
Sound Card Benchmarking
  • PC performance issues may be related to your
    sound card
  • Theres a benchmark utility available called
    AudioWinBench
  • www.veritest.com/benchmarks/winbench/winbench.asp

42
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