Sound

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Sound

• Chapter 15
• Mike Fuszner

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Types of Sound On a PC

• WAV
• Musical Instrument Digital Interface (MIDI)

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WAV

• 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.

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WAV

• 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

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WAV

• The sampling rate for a digital waveform is
  measured in thousands of time per second or
  kilohertz (KHz).
• It usually varies from 11 to 44 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

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WAV

• 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.

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MIDI

• Musical Instrument Digital Interface
• 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.
• MIDI starts with a sound card that has built-in
  recordings of real musical instruments.
• More expensive sound cards have larger numbers of
  instruments and better quality recordings

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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.

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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 or
  Wavetable synthesis (higher quality).
• Great for storing music but cant save a human
  voice or an explosion

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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.

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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

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Sound Card Connections

• Speakers
• Microphone
• Line In/Line Out
• CD Media
• MIDI/Joystick

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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

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Microphone

• Connected to the sound card through a mini audio
  connector.
• Problems with microphones generally point to the
  microphone itself.

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Line In/Line Out

• 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.

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CD Media Sound Cards

• Old sound cards provided support
  for an ATAPI CD-ROM drive via
  an onboard 40-pin
  connection.
• CD media and sound cards can
  also be connected using the
  expansion bus itself
• When you select a file from Media Player, it is
  loaded into RAM via the expansion bus. When
  played it goes over the expansion bus from the
  CD-ROM to the sound card.

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CD Media Sound Cards

• A CD-ROM drive can play audio CDs by itself
• Use the CD-ROM drives speaker jack and a second
  set of speakers
• Or link the CD-ROM drive to the sound card using
  a special wire to play the audio thru your
  existing speakers

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MIDI/Joystick

• MIDI has the ability to connect to other MIDI
  devices through a 15-pin female DB-type
  connector.
• The MIDI connector also acts as a game port for a
  joystick.
• Most sound cards autodetect the presence of a
  joystick, but some old cards require
  configuration of jumper settings.

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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

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Windows 9x/2000

• PnP in Windows 9x and Windows 2000 has made
  non-PnP soundcards obsolete.
• Windows now includes a basic, but complete set of
  applications for playing and recording WAV files,
  MIDI files, and CD-ROMs.

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Device Manager

• Can be used to find any device recognized by
  Windows 9x/2000.
• The Device manager displays the several functions
  of a sound card as separate devices.
• OPL3 is a MIDI device

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Device Manager

• PnP sound cards rarely have resource issues, but
  occasionally you may have to resolve an issue.

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Control Panel ? Sounds and Multimedia (Windows
2000)
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Volume Control in the Tray
Options ? Properties Windows 2000
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Multimedia

• The Windows 9x Multimedia menu is divided into
  five tabs
• Audio
• Video
• MIDI
• CD Music
• Advanced

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Troubleshooting
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Physical 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.

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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.

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Support Resources

• The support programs are divided into two groups
  codecs and DirectX. These are programs that are
  put between the Device Driver and the application.

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Codecs

• Pure waveform files are large
• Near CD-quality wave files average about 10 MB
  per minute of sound
• Codecs reduce this size thru compression and
  decompression.
• Windows provides a broad cross-section of codecs,
  which any sound application can access, leaving
  the sound application to their own jobs.
• Most codec problems can be fixed by downloading
  the desired codec from the Internet.

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Codecs
Indicates you have the wrong codec youll need
to find it on the Internet and download it.
The file properties will show you what codec the
file needs to play.
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DirectX

• Provides applications, primarily games, with
  virtually complete direct access to the hardware.
• DirectX has gone through a number of version
  changes over the last few years.
• Youll need 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.

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DirectX
Access the DirectX Diagnostic Tool from the Tools
? Windows menu in Computer Management in Windows
2000
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DirectX Diagnostic Tool
Try testing by clicking the testing button on
some of the tabs!
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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.

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Beyond A
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Beyond A

• 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

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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

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Dolby Pro Logic
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Dolby Digital 4.1
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3-D Sound on the PC
Advanced button under Sound Playback under the
Audio tab in Sounds and Multimedia applet in
Control Panel shows the proper positioning of
your speakers.
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Connections on 5.1 Sound Card
Digital Out.Orange Line
In..Blue Microphone..Pi
nk Output to front speakers..Green Output to
rear speaker.Black
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