1. Audio Communications: Sound Mr. Butler Communication Systems John Jay High School Wappingers Central School District UPDATED 11/2011

2. Why is it important to learn about sound?  Sound is becoming increasingly important when designing for new media and Internet.  You don’t have to be a musician to be a sound designer, but familiarity with all types of audio is important.

3. Sound Frequency  Sound is composed of a complex set of waves. These waves vibrate at different frequencies. High frequencies are defined and controlled by the TREBLE knob on your amplifier High frequencies are defined and controlled by the TREBLE knob on your amplifier Low frequencies are controlled by the BASS knob Low frequencies are controlled by the BASS knob

4. Analog Audio Theory What is Analog Audio? Analog means that the sound has been recorded on an analog medium, most likely tape Analog means that the sound has been recorded on an analog medium, most likely tape Analog also means that each copy is NOT going to be equal to the original. Analog also means that each copy is NOT going to be equal to the original.

5. Digital Audio Theory Advantages of Digital Audio Each copy is EQUAL to the original, and there is no generation loss. Each copy is EQUAL to the original, and there is no generation loss. This is why the music business moved to CDs. This is why the music business moved to CDs.

6. Frequency Range  For most professional applications, it is desirable to record the original sound in as high a quality as possible and then sample it down.

7. Frequency Range  The normal range of human hearing is 20 to 20,000 Hertz, or cycles per second. Only very high quality sound systems and headphones are capable of reproducing this range.  Small computer speakers are capable of reproducing a more limited range of frequencies.

8. Dynamic Range  Dynamic range is the degree to which the sound gets louder and softer.  The wider the dynamic range, the more natural a sound appears and he greater the emotional impact.  Most recording systems seek to have the widest dynamic range possible.

9. Formats  Sound use to come in only two media, tape and vinyl. Now, myriad formats are available, including CD and Minidisk.  Some common computer formats include MP3, AIFF, WAV.

10. MIDI  MIDI: Musical Instrument Digital Interface  MIDI was developed in the mid-1980s  Allows keyboard synthesizers talk to the computer.  Ringtones

11. Audio on the Internet  MP3 is a technology that created its own industry.  Fueled mainly by college students, MP3 was a quick way to exchange and share music over the Internet.

12. Audio Internet Formats  There are many different formats for audio on the Internet, but five of them are the most common. MP3 MP3 RealAudio RealAudio Windows Media Player Windows Media Player QuickTime QuickTime AIFF and WAV AIFF and WAV

13. MP3  the file extension for MPEG Audio Layer-3, standards for compressing and downloading audio files from the Internet.  the file extension for MPEG Audio Layer-3, a set of standards for compressing and downloading audio files from the Internet.  Most popular format  Widely used for exchange music files  Good compression scheme  Typical size per song: 3 to 4 MB.  Although the legal issues are still being worked out, MP3 is here to stay.

14. QuickTime  Apple Computer Product  QuickTime recently converted to a streaming format  Before QuickTime, you had to download QuickTime files.

15. AIFF and WAV  AIFF stand for Audio Interchange File Format  WAV files are called “wave” files. Both are high-quality audio files, and both require a lot of memory.  If you want CD-quality sound, AIFF or Wav will deliver it.

16. References  Digital Creativity, “Techniques for Digital Media and the Internet”-Bruce Wands