These steps and tips are intended to help with the process involved when you
want prepare a sound clip, for use in a variety of applications. A quick,
but very important, reminder before getting started is in order. It is
your responsibility to follow any copyright laws and "fair use" guidelines
that may pertain to what you are doing. If you are not sure, check with
a Library Media Specialist on your campus. You may find it helpful to visit The Copyright Site to
find out more about copyright and fair use guidelines.
There is no question that music can build mood - excitement,
anticipation, danger, etc., communicate emotion - sadness, pride,
joy, capture and hold the attention of your audience, reinforce
interactivity with button sounds, make the audience feel like
they're somewhere else, and give projects that "professional" feel. However,
music, especially background music, need not always be "embedded" into
a presentation to make it effective. Playing music from a portable
CD player (jam box) can provide several advantages. You also
have the option of having PowerPoint or other multimedia authoring
application, just cue and play the CD track "live" during the
presentation as well. (Make sure you test thoroughly using the
hardware that will be used at the actual presentation though
when planning to use this method.)
There are many factors that can help you determine which way
to go. Some are: 1) file size and portability, 2) file size and
load time, 3) overall length of presentation, number of clips,
and how much sound (total length), 4) location, equipment, network
access at the final presentation spot, 5) copyright and fair
use issues 6) did I mention file size and hardware performance
As with any multimedia project, make sure you determine your target
audience (the ultimate users that will experience or interact
with your production), your "end result" performance
environment (is this project being developed primarily
for a "live" presentation, a cd-based experience,
a Web-based delivery, VCR tape medium, etc., and what hardware and software
will be available for the end user's (possibly yourself)
when this project is delivered or experienced. This should include
consideration of the quality of audio (sound) playback equipment
as well. Once these elements are defined and planned, then
begin the development (time investment) of your project. Knowing
these elements in advance will likely help you make much wiser
choices during development, save "re-do" time, and
ultimately lead to a more successful end product!
Digital Audio Terms:
AU (U-LAW) – Older audio compression file format,
Sun Microsystems format that is popular in the Unix world. However,
they have comparatively poor sound quality.
WAV (WAVE) – Standard Windows Format - A digitized
sound file format for Microsoft Windows, which has ".wav" as the
AIF (AIFF) – Standard (native) MAC Format for digital
MIDI (Musical Instrument Digital Interface) – A way
of communicating instructions for playing music from one electronic
device to another; for example, from a synthesizer to a computer
to a musical instrument. MIDI includes hardware (the electronic instruments
and the interface between devices) and software (the set of rules
for encoding and transfer of sound information). With MIDI, a musician
can use a keyboard to simulate the sounds of many different instruments,
plus add special effects. MIDI files are very small compared to many
other audio file formats and can be a very effective choice for digital
use. However, the quality and range of tones used by this format
is very limited. The resulting playback will use a set of standard
synthesized instrumental sound tones. It will work well for some
projects, it will depend on the reproduction quality you are after,
as well as the access you have to the tools needed to prepare them
and the playback ability of your target application. Because of it's
small file size (fast download), midi has been an early "music" clip
format favorite on the Internet.
MP3 – Popular Internet compression format - MP3 stands
for "Motion Picture Experts Group, Audio Layer 3 Compression". A
popular music download format, MP3 produces near-CD-quality music
in a compressed file that can be transferred quickly, and played
on any multimedia computer with MP3 player software. The technology
creates sound files a tenth the size of standard CD music files with
very little loss of sound quality.
WMA/AAC - Popular highly compressed format. These
formats (WMA for Windows, AAC for Macs and iPods) are compressed
to even smaller file sizes than MP3, but still retain a relatively
high quality playback level. However, they generally require certain
applications or devices for playback, thus, they are not completely
reliable or compatible...yet, for inserting into PowerPoint or similar
applications. Just make sure and test thoroughly before depending
on them in your presentations and playback equipment.
RM (RealMedia) RAM, RA, etc. – Standard RealPlayer/RealAudio
MPEG-1. An ISO (International Standards Organization)
group that sets standards for compressing and storing video, audio,
and animation in digital form. 2.The standards set by this group.
MPEG is a lossy compression method. MPEG-1 is a standard for
CD-ROM video and audio. MPEG-2 is a standard for full-screen,
broadcast quality video. MPEG-4 is a standard for video telephony.
MOV (Movie)– Standard QuickTime format for movies and
audio. Can also be audio only.
AVI (Audio Video Interleaved) – Standard Windows Video
format. Can also be audio only. AVI is a Microsoft multimedia file
format, similar to MPEG and QuickTime, used by Video for Windows.
In AVI, audio and video elements are interleaved (stored in alternate
segments) in the file.
Sample Rate - A sample rate (frequency) is the way a sound
file is recorded. Sound Companion defaults at a Sample Rate of 22.05
KHz. What this means is that you will record @ 22.05 kilobytes per
second. If you multiply this out, a one-minute file would be about
1.2 MB in file size. (Remember a regular floppy disk holds about
Bit Depth - Bit depth can be set at 8 or 16 bit. Sound Companion
defaults to record at 16 bit. Bit depth describes the potential accuracy
of a piece of hardware or software that processes audio data. Bit
depth is the number of "bits" you have in which to describe
something. Reminder a "bit" (short for binary digit), is
the smallest unit of data in a computer. It has a single value, either "0" or "1".
In most computer systems, there are eight bits in a "byte".
For a more technical and thorough understanding and relevance to
digital audio, visit Principles
of Digial Audio
Here are some common general settings to
For "voice only" recordings: 11.025KHz - 16 bit
For "voice with background music": 22.05 KHz - 16 bit
For "sound clips recorded from a music CD": 22.05 KHz - 16 bit
can get you started, but remember, you will usually want to go with those
settings that strike an acceptable balance between file size and
acceptable playback quality based on the target audience and target
performance equipment that your project will be presented or played
Related Web Resources:
Note: some of these sites will not be accessible from a district
machine. They are here as supplemental resources. You may be able
to access them at home, if you choose to. Neither David Hitt nor
PISD is responsible for the contents of remote sites or servers.
If accessing any of these sites from a Plano ISD computer,you must
follow and abide by all PISD Acceptable Use Guidelines for Technology
Make sure you follow legal and ethical use of all digital audio
files. Read all documentation closely before using and/or editing
sound clips from various sources. It is your responsibility to follow
copyright and fair use guidelines. Your campus librarian can help
with questions about this.
This is not an endorsement or recommendation to download or use
any files and/or applications or plug-ins that may be available
from these sites. It is intended as a resource to find out more
about the various digital sound formats.
WAV and MP3:
http://electronics.howstuffworks.com/mp3.htm/printable - "How
MP3 Files Work".
the Associated Press/AccuWeather Multimedia Archive to search for
sound files. (As this is a subscription-based service, remember that
it can only be accessed when on the PISD District Network or via
a Remote Access or MyPisd account login.)
Click on "Articles" for many tutorials, tips, and other "how-to's".