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Sound. Chapter 18. 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. How Sound Works in a PC.
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Sound Chapter 18
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
Sound-Capture Basics • Four components for capturing and outputting sound • Sound card • Speakers • Microphone • Recording/Playback software
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?
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)
Sound-Capture Basics • 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
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
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
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 • 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)
Other File Formats • Over 100 sound formats • Table lists just a few
Video • Videos typically have sound built in • Some common video formats are
Applications • Many applications (especially games) play sounds • Most use the standard WAV, MP3, or MIDI file formats
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
Essentials CompTIA A+Essentials Getting the Right Sound Card Getting the Right Sound Card
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
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
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
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
Sound Card Connections • Main stereo speaker is blue • Line out connector is green • Microphone connector is pink
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
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
Speaker Standards • Stereo • Left and right • 2.1 systems • Pair of speakers called satellites and a subwoofer
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 Surround-Sound Standards
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
Speaker Features • Controls • Volume controllers • On/off switch • Can be on speakersor on special box • Headphone jack • Some systemscan automaticallysense when plugged in
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
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
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
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
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
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
IT Technician CompTIA A+Technician Troubleshooting Sound
Hardware Problems • Volume • 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
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
Application Problems • First, look for an error message • Check the application’ssupport site • Second, check the sound file • Sound files might be corrupted • Last, reinstall the application
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