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 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.”

How Sound Works in a PC

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) 6

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

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.

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 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.

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 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

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

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

Getting the Right Sound Card 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 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.

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 2.1 systems Left and right Pair of speakers called satellites and a subwoofer

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.

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 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

Installing a Sound Card in a Windows System

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.

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.

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.

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

Troubleshooting Sound IT Technician CompTIA A+ Technician Troubleshooting Sound

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

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’s support 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 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.