1. Sound
Chapter 18

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
Instructor Tip
When gaining attention and establishing common ground, ask questions of the class, such as, “Does anyone here have a computer without a sound card? Believe it or not, a sound card was regarded as an optional computer device not too many years ago,” or “How many of you have ever installed a sound card?”
For a positive statement, tell the class, “In this lesson, we are going to learn how sound cards work, about the various types of sound cards, and how to install and troubleshoot them.”

3. How Sound Works in a PC

4. Sound-Capture Basics
Four components for capturing and outputting sound
Sound card
Speakers
Microphone
Recording/Playback software

5. Sound-Capture Basics Sampling—capturing sound
Sampling rate is measured in cycles per second (KHz)
Low quality (11 KHz) to high quality (192 KHz)
Doesn’t capture every nanosecond of sound
Takes samples and extrapolates, or predicts, what the data is between samples
Dotted line—can you connect the dots?

6. Sound-Capture Basics Sampling—capturing sound
Bit depth—Number of characteristics of a particular sound (for each sample)
Amplitude (loudness)
Frequency (tone)
Timbre (qualities from different instruments) 6

7. Sound-Capture Basics Tracks CD quality
Waveforms are commonly sampled with either 8 or 16 bits per sample
8-bit stores 28 or 256 different characteristics
16-bit stores 216 or 65,536 different characteristics
Tracks
Monaural—one track
Stereo—two tracks
CD quality
44.1 KHz
16 bit depth

8. Recorded Sound Formats
Pulse code modulation (PCM)
Developed for telephone calls
Better known as the WAV format
Large files
Four-minute song at 44.1 KHz and 16-bit stereo is greater than 40 MB
Compressor/decompressor (CODEC) programs
Algorithms developed to compress sound files
MPEG-1 Layer 3 codec or MP3 is one example of a codec
WAV and MP3 are only two among a large number of file formats for sound. Not all sound players can play all of these formats; however, many sound formats are nothing more than some type of compressed WAV file, so with the right codec loaded, you can play most sound formats.
Tech Tip
Compressing WAV Files to MP3 Format
Using MP3 compression, it is possible to shrink a WAV file by a factor of 12 without losing much sound quality. When you compress a WAV file into an MP3 file, the key decision is the bit rate. The bit rate is the amount of information (number of bits) transferred from the compressed file to the MP3 decoder in one second. The higher the bit rate of an MP3 file, the higher the sound quality. The bit rate of MP3 audio files is commonly measured in thousands of bits per second, abbreviated Kbps. Most MP3 encoders support a range of bit rates from 24 Kbps up to 320 Kbps (or 320,000 bits per second). A CD-quality MP3 bit rate is 128 Kbps.

9. Playing Sounds
Every sound card can play WAV files using sound player software
Windows Media Player comes with Windows
iTunes is Apple’s media program
Many other good sound players are available

10. MIDI Musical Instrument Digital Interface
MIDI file is a text file
Contain a series of commands that describe
What note to play
How long to play it
Which instruments to use
Tiny in size compared to WAV files
Beethoven’s Fifth Symphony is 78 MB as a WAV file and 60 KB as a MIDI file
MIDI files are much less popular than recorded formats on PCs. Every Windows computer and every sound card still fully supports MIDI, however.
MIDI files have the file extension .MID in the PC world.

11. MIDI Sound cards play MIDI files using one of two technologies
FM synthesis
Strictly electronic—software says what to play
Wave table synthesis
Uses recorded sounds (WAV files) to start
Modifies characteristics of sounds to create amplitude, frequency, and timbre desired
Polyphony of card—how many instruments it can play at once (128 instruments is common)

12. Other File Formats Over 100 sound formats Table lists just a few
Acronym
Description
AAC
Advanced Audio Coding—native format for Apple’s iTunes
AIFF
Audio Interchange File Format—popular with Macintosh computers
ASX
Microsoft Advanced Streaming Redirector AU
Can be played in Windows, Sun, Next, UNIX and Macintosh
OGG
Vorbis format—open source codex RM
RealMedia—audio, or audio and video
WMA
Windows Media Audio—proprietary

13. Video Videos typically have sound built in
Some common video formats are
Acronym
Description
AVI
Audio Video Interleave
MPEG
Moving Pictures Experts Group
MOV
QuickTime
ASF
Advanced Streaming Format RM
Real Media
WMV
Windows Media Video
DivX
Often used for ripping audio and video
Flash
Used on YouTube

14. Applications Many applications (especially games) 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
Apple’s iTunes

16. Getting the Right Sound Card
Essentials
CompTIA A+ Essentials
Getting the Right Sound Card
Getting the Right Sound Card

17. Sound Cards A sound card typically has many built-in features
Two separate processors (one for MIDI and one for the rest)
Support chips for joysticks
Recording capabilities
MIDI support
More
Can be a separate sound card
Often just a chip built in to the motherboard
The most famous of all sound cards is Creative Labs’ popular SoundBlaster series.
Tech Tip
Sound Cards
The hardware portion of sound-processing equipment in the PC comes either as a chip built-in to the motherboard or on an expansion card. Techs call both forms sound cards even though, technically, the first type is not a card at all. Still, the generic term has stuck for the time being.

18. Sound Card Differences
Sound cards differ in five basic areas:
- Processor capabilities - Speaker support
- Recording quality - Jacks
- Extra features
Processor handles communication between the application, OS, 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 and provides better sound quality

19. Sound Card Differences
Speaker support
Basic support—two speakers or headphones
Better sound cards support five or more speakers
Often have a subwoofer
5.1 means 5 speakers with 1 subwoofer
Recording quality
Signal-to-noise (S/N) ratio expressed in decibels
Low end have S/N ratio of 30 to 50 decibels
Records artifacts (noise) when there is no actual noise
High-end cards offer a 96 to 100+ S/N ratio

20. Sound Card Differences
Jacks
Line In and Line Out converters enable the sound card to send and receive input and output from other devices
The Line In connector runs to a Line Out or Aux connector on the back of a stereo receiving system
Rear Out connects to the rear speakers for surround sound
Analog/Digital Out for external digital connections
Microphone & Joystick

21. Sound Card Connections
Main stereo speaker is blue
Line out connector is green
Microphone connector is pink

22. Sound Card Differences
Extra Features
Almost all motherboards have built-in sound
Extra goodies needed to entice buyers
Digital output to integrate PC with home entertainment system
DVD receiver
Surround-sound speaker connections
Breakout box adding ports to front of PC
More

23. Audio Cables
To play audio CDs through your sound card requires a cable from your optical drive to the sound card
Most optical drives come with an MPC2 audio cable for this purpose

24. Speaker Standards Stereo 2.1 systems Left and right
Pair of speakers called satellites and a subwoofer

25. Surround-Sound Standards
Dolby Digital
Supports five channels plus subwoofer (5.1)
Front right, front left, front center, rear left, rear right
Digital Theatre System (DTS)
Competing standard that also supports 5.1
Sony/Philips Digital Interface (S/PDIF)
Uses single connector for entire 5.1 system
Note: Both jacks pictured are S/PDIF jacks. The jack on the right accepts a TOSLINK connector. The orange jack accepts a RCA connector.

26. Surround-Sound Standards
DirectX provides applications, primarily games, with direct access to hardware
Offers developers easy-to-use commands
Easy to program sounds in the desired channel
DirectSound3D (DS3D)
Can place a sound anywhere in 3D space
Known as positional audio
Environmental audio extensions (EAX)
Creative Labs’ response to DS3D

27. Speaker Features Controls Headphone jack Volume controllers
On/off switch
Can be on speakers or on special box
Headphone jack
Some systems can automatically sense when plugged in

28. Installing a Sound Card in a Windows System

29. Physical Installation
Installs like any other PCI card
Plug in the card
Load the drivers
Test
Hardest part may be identifying where to plug in speakers
Refer to documentation
Typical stereo or 2.1 speaker system plugs into Speaker or Speaker 1 port
Surround-sound speakers use single S/PDIF
Exercise
Sound Card Installation
Now that you have discussed what a sound card does, have the students install one. Installation is pretty straightforward. Have the students open the case (make sure the power cord is unplugged) and install the card. Also make sure the card is grounded (screwed in). Make sure students plug in the CD-ROM patch cable. If sound card is not a PnP card, make sure they set the jumpers correctly. Above all, ensure students are properly grounded and taking all ESD precautions. Have them boot the computer and install the drivers. Then have the students follow along for the rest of the lecture, checking the Device Manager and the Sounds and Audio Devices applet in the Control Panel, etc.

30. Physical Installation
Basic steps
Shut down your computer, unplug it, and open the case
Find an open PCI slot and install card
Connect the CD audio cable to the drive and the card
Exercise
Sound Card Installation
Now that you have discussed what a sound card does, have the students install one. Installation is pretty straightforward. Have the students open the case (make sure the power cord is unplugged) and install the card. Also make sure the card is grounded (screwed in). Make sure students plug in the CD-ROM patch cable. If it is not a PnP card, make sure they set the jumpers correctly. Above all, ensure students are properly grounded and taking all ESD precautions. Have them boot the computer and install the drivers. Then have the students follow along for the rest of the lecture, checking the Device Manager and the SOUNDS control panel, etc.

31. Installing Drivers Let Windows install drivers
If necessary/desired, use CD that came with sound card
If installing a USB sound card
Follow the cardinal rule for USB drivers: Install the USB driver before the USB device
Verify driver is installed by checking Device Manager
Test
Sound card drivers are updated occasionally. Take a moment to check the manufacturer’s Web site to see whether or not your sound card has any driver updates.

32. Configuration Applications
Most sound card configurations can be done within Windows
Use the Sounds and Audio Devices applet in Windows XP’s Control Panel
Or Sounds and Multimedia in Windows 2000
Five tabs
Volume
Sounds
Audio
Voice
Hardware

33. Proprietary Configuration Apps
Many sound cards install proprietary software
Adds access to other features that aren’t otherwise available
Autosensing—allows hardware to be plugged in using different ports and the ports adjust
Plug microphone into speaker port and speaker port becomes a microphone port

34. Installing Applications
Some sound cards install extra software
Goal is to provide user with extra free software
These programs aren’t needed to use any of the features
Intended to provide extra value for the purchase

35. Troubleshooting Sound
IT Technician
CompTIA A+ Technician
Troubleshooting Sound

36. Hardware Problems Volume Speakers Check physical controls
Check software controls
Windows Volume controls
Speakers
Ensure they are turned on and getting good power
Make sure they are plugged in
Check for visual indicators that a sound is playing
Replace speakers if blown speakers suspected

37. Configuration Problems
First place to check: Device Manager
Consider reinstalling driver
Ensure the latest device drivers are installed
Check the manufacturer’s Web site for updates
Review the Sounds and Audio Devices applet settings

38. Application Problems First, look for an error message
Check the application’s support site
Second, check the sound file
Sound files might be corrupted
Last, reinstall the application

39. Beyond A+ Sound card benchmarking
PC performance issues may be related to your sound card
Analyze your sound card with RightMark 3DSound from iXBT.Com/Digit-Life
Exercise
Troubleshooting
Once again, create a “service call” for students. Change settings, create IRQ conflicts, incorrectly set jumpers (if available), plug speaker wires into the wrong port, unplug the AC power from the speakers, and so on.