AUDIO MEDIA

© Anthony J. Nowakowski, Ph.D.

AUDIOMEDIA

EDC 601 Instructional Technologies


“Sound also adds to the interpretation of the text. If you are an audio learner, you key in on the sounds as much as you key in on the graphics and text. No matter what type of learner you are, the addition of audio will increase your learning productivity. The Audio sub-topic presents information on various phases of audio including how we hear, wave forms, digital audio techniques, sound types, and audio file formats. As you study this section, think about the different types of sound, how they are created, and how you might use sounds in a multimedia project.”

(Sprankle and Johnson)



“Speech in the form of narration or dialog can teach effectively in your multimedia application. To enhance the direct statements, a speech segment can also convey meaning through: Emphasis. Emphasis increases when a speaker stress a word Inflection. Inflection alters the pitch or tone of spoken language such as a rise in pitch at the end of a sentence to indicate a question. Aural mood. Speech establishes aural mood through specific word choices such as crashed versus hit or fantastic versus good.”

(Fenrich, 1997, p.129)



When dealing with audio media, there are two different approaches to recording, saving, and

playing these media:

Recorded Sound soundsound voice music



MusicSynthesized Music

Recorded Sound soundsound voice music

When dealing with audio media, there are two different approaches to recording, saving, and

playing these media:



AUDIO FILEFORMATS



.WAVe (PC) .AIFf (Mac) .AUdio (Sun - Unix & PC) Others

Synthesized Formats .MIDi (PC & Mac) .RMI (PC)

Waveform Formats

See Table 5-4 for a comprehensive list of audio formats

See Table 5-4 for a comprehensive list of audio formats



When dealing with sound, there are 3 factors.

Anthony J. Nowakowski, Ph.D.

CIS 594 Multimedia for Educators

AUDIOAUDIOMEDIAMEDIA

1. # of channels

2. Sampling rate

3. # of bits of sound



SoundMono - 1 channel (track)

Stereo - 2 channels (tracks)



1 second

Continuous (analog)

Sound



1 second

Sampled 25/sec. (digital)

Sound



Human hearing 20 - 20,000 cps (Hz)

8 bits of sound 28 = 256 different frequencies

19,980 / 256 = 78 cps steps

Sound



Human hearing 20 - 20,000 cps (Hz)

8 bits of sound 28 = 256 different frequencies

19,980 / 256 = 78 cps steps

16 bits of sound 216 = 65,536 different freq.

19,980 / 65,536 = .3 cps steps

Sound



.WAVe files (record/play sound waves)

voice - 11,025 times/sec. sampling rate

8 bit sound

mono

3.5” HD diskette holds 131 sec.

Sound



.WAVe files (record/play sound waves)

CD - 44,100 times/sec. sampling rate

16 bit sound

stereo

3.5” HD diskette holds 8 sec.

Sound



.MIDi files (synthesize musical instruments)

Like sheet music frequency duration “voice” - (piano, drums, guitar, sax)

94 second score is only 28kSee Table 5-3 for a

comprehensive list of voicesSee Table 5-3 for a

comprehensive list of voices

Sound



WAVe vs. MIDiAlthough waveform files allow the recording, editing, and playback of sound, voice, and music, they usually require large file sizes. A typical voice recording in mono and with an 11 K sampling rate requires approximately 11,000 bytes/second and a CD quality recording in stereo with a 44k sampling rate requires approximately 176,000 bytes/second. Whereas, a typical MIDI file requires approximately 200 bytes/second! However, MIDI files can only contain the instructions to play music, and the creation of a MIDI file requires a MIDI device (keyboard) and musical talent. However, you can find MIDI editors on the Internet.



AUDIOSOFTWARE



Audio SoftwareMedia Player (Windows) - player for WAV, WMA, MID, and many other audio file types.

Sound Recorder (Windows) - player, recorder, and limited editor for WAV files. (Only a recorder with Vista.)

Goldwave (www.goldwave.com) - editor, player, recorder, and converter for numerous audio file types.

Audactiy (audacity.sourceforge.net) - editor, player, recorder, and converter for numerous audio file types.



Consider the

following example:



When I was using PowerPoint 97, I wanted to use DIESEL.AU, a file that I found on the Internet as a sound effect in my presentation. However, PowerPoint 97 only plays WAVe files, and the file was too long (48 seconds).





48 seconds



14 seconds





CreatedCreated}

“Borrowed”“Borrowed”}

• Microphone

• MIDI keyboard

• CD’s & disks

• Internet

Audio Sources



8 11 KHz / Mono lowest standard that should be used

8 11 KHz / Stereo no advantage in using stereo

8 22 KHz / Mono sounds like AM radio

16 22 KHz / Mono okay for narrations

16 44 KHz / Stereo CD-quality sound

# of bits sampling rate uses

File Size Considerations

See Table 5-2 for additional examplesSee Table 5-2 for additional examples



compressed vs. uncompressedcompressed vs. uncompressed

Similar to what we saw with graphics files, depending on the format that is used, audio files can use different amounts of space. As an example, Diesel.AU requires 380Kbytes while Diesel.WAV requires 760 Kbytes. Although, AU files require less space, many applications are unable to use sound files in this format.

File Size Considerations



“Audio compression techniques can provide important benefits for applications stored on CD-ROMs and hard disks, since uncompressed audio requires significant storage space. Digital audio is fairly difficult to compress, and no standardized compression/decompression technique has yet emerged. Some sound boards can perform the relatively common ADPCM (Adaptive Differential Pulse Code Modulation) compression/decompression technique.”

(Fenrich, 1997)

We can see which “codecs” are installed on a computerby going to Start, Settings, Control Panel, Sounds and Devices, Hardware tab, and scroll down to Audio Codecs.

See ekei.com/audio/ for a discussion ofcompression algorithms.

We can see which “codecs” are installed on a computerby going to Start, Settings, Control Panel, Sounds and Devices, Hardware tab, and scroll down to Audio Codecs.

See ekei.com/audio/ for a discussion ofcompression algorithms.



Download vs. Streaming



Received first,

then played

Software is needed to:

create

play

Initial download

“Buffered”

ongoing download with

simultaneous play back

Software is needed to:

create

serve

play

Download vs. Streaming



Audio

Sound.WAV

.SND

.AU

…etc

Music.MIDi

.MP3

.RA/.RAM

.ASF

.MP3

(Downloaded) (Streamed)



Addins and Helpers

Helpers - Run in, as well as outside of a browser.

Adobe Acrobat ReaderRealNetwork RealPlayer

Plugins/Addins - Run ONLY inside of a browser.

Macromedia Shockwave for Director



MP3 a challenge to CD’s???

MP3 a challenge to CD’s???

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