1. Sound Chapter 15

2. 2 Types of Sound Waveforms MIDI Sound is related to many things in computers but only Wav and MIDI exist in PCs.

3. 3 Waveforms Sound travels in waves High sounds are taller waves and low sounds are shorter waves Waveforms are recorded on the computer as 1’s and 0’s Waveforms are recorded in a number of tracks Waveforms are commonly sampled with 8 or 16 bits 8 bit samples store 256 different frequencies 16 bit stores 65,536 frequencies

4. 4 Waveforms Waveforms are measured in kilohertz Usual variation of kilohertz is 11 to 44 The higher the number of KHz, the better the quality Waveforms are very large files and some can take over 1MBps In the beginning there were many forms which each needed its own application Now there is WAV format for Windows which is the most popular form of waveforms

5. 5 MIDI Musical Instrument Digital Interface MIDI was not created for PCs Created for musicians to create, store, and play a broad cross section of instruments MIDI starts with a sound card with recordings of musical instruments Number and quality of recordings tells which sound cards are more expensive Functions much like sheet music Each instrument is called a voice

6. 6 MIDI The number of different instruments played at once is called the polyphony Two methods for storing musical instruments: FM synthesis Wavetable synthesis Wavetable is much better than FM

7. 7 Sound Cards Device that can translate or record both MIDI and WAV formats They take the digital sound as input and turn it into analog sound for speakers

8. 8 Sound Card Connections Average sound card can perform these functions:  Record and play waveform files  Record and play MIDI files  Enable recording via microphone or auxiliary input  Assist the playing of analog CD-ROMs from the CD-ROM drive Different sound cards provide different functions

9. 9 Speakers Enables sound to be output to speakers Classic PCs are compatible with only two speakers for stereo New PCs are compatible with many speakers because of 3D sound Most speakers require a battery or AC adapter for them to amplify sound If there is a problem it is most likely because of the speakers and their power Powered speakers without power will make faint sounds but must be turned off

10. 10 Microphone Also are connected directly to the sound card Full sized microphones must use adapters Most problems with microphones are because of the physical microphone and not the connection or card Be sure to check the power switch or batteries

11. 11 Line In/Line Out Allow sound card to send and receive input and output from devices other than a microphone or speaker Sound card can take in info from any device connected to it Sound card can also be connected to stereo system to send its own sounds to external speakers

12. 12 CD Media Connected in 3 different ways:  ATAPI CD-ROM via 40-pin connection  Connection had nothing to do with sound; only the transfer of data from the drive  Use expansion bus itself  Must use media player and open the file  File is run through the bus again and sent to the sound card  Problems are caused by I/O, IRQ, or DMA  CD-ROM Connections  Cards have a special CD-audio connector that links directly to the card

13. 13 MIDI/Joystick MIDI enabled cards have a 15-pin female DB connector Used to plug in MIDI instruments to the card Looks much like joystick port Sound cards now have the ability to configure the port properly to support joysticks so that customers won’t call with complaints

14. 14 Device Drivers Sound cards have complicated device drivers Remember:everything as separate device  Not: Sound Card  Think: MIDI Card, WAV card, etc.

15. 15 Windows 9x/2000 PnP has made non-PnP cards obsolete Most current sound cards come with the basic software needed for any playing or recording There are a few nuances

16. 16 Device Manager Device Manager detects anything recognizable by Windows Occasionally there is a problem  Can be changed through the properties for that particular drive Once sound card is recognized without errors it is ready to go

17. 17 Control Panel Use this to test the sounds Just to make the speakers make some noise If play button is not clickable then something is wrong in device manager Click icon in system tray once to open speaker volume Two clicks opens main Volume Control Settings

18. 18 Multimedia Rarely used Five different sections:  Audio  Video  MIDI  CD music  Advanced

19. 19 Troubleshooting Sound All sound problems can be broken down into three different groups  Physical problems  Driver issues  Support resources

20. 20 Physical Problems Something isn’t turned on, plugged in, or turned up Easiest of the three problems Check all connections and volume settings  Volume can be changed in four different places  If any are down the sound will be down Bad wires are likely if there is a cracking sound coming through the speakers

21. 21 Drivers Install the latest drivers Try to uninstall/reinstall Use device driver repair methods noted earlier in the book

22. 22 Support Resources Many little programs that Windows puts between the device drivers and the applications Two groups:  Codecs (compressor/decompressor)  DirectX If application refuses to play specific sound file check to see if you have the correct codec installed Codec problems can be fixed by downloading the correct one

23. 23 DirectX Windows did not get along with many popular games Needed to run in DOS Microsoft developed DirectX to give the programs almost direct access to the hardware There are many versions of DirectX and each game requires one model The box will usually state the version of DirectX to use

24. 24 Application If a sound won’t play in an application  Check control panel to test sounds  If sound works here there is a problem with the application  Check the application’s sound properties