|A Caller's Perspective on Digital Music
(by Vic Ceder)
|Digital Music Interest Session
This paper is a primer for square dance callers interested in
using MP3 files and a laptop computer.
This paper addresses the following:
- Media for reproducing music
- How to obtain digital music
- Copyright considerations
- How to use MP3 files
- Advantages and disadvantages of using MP3
- How to convert a 45 RPM record to MP3
- How to convert an audio CD to MP3
- My perspective on using MP3
- Advantages and disadvantages to using a laptop
- Selecting a laptop
- Suggested software
- Other thoughts on digital music
|Media for Reproducing Music|
There are many ways to reproduce music, some you're probably
already familiar with and others that may be new to you.
A Record is a vinyl disc containing a single spiral track of physical
grooves of variable size and depth. When a phonograph needle passes along
the groove, the size characteristics of the groove cause the needle to
vibrate, which produces sound. Vinyl is not re-writeable. Characteristics
of records are:
Analog -- the music is recorded in a continuous wave format.
Random access -- the phonograph needle can be lifted up and placed
down on the record at any desired location.
Magnetic Tape (Cassette, Reel-to-Reel) is a
thin plastic tape coated with magnetic material.
Magnetic tape is re-writeable, but is generally not useful to callers
because it is sequential access. Characteristics of magnetic tape are:
Analog -- the music is recorded in a continuous wave format.
Sequential access -- to play the music at a
desired location, you must rewind or fast-forward
the tape to the desired location.
Digital Audio Tape (DAT) is a high quality cassette tape, using
digital encoding (like a CD-ROM). DAT is generally not useful to callers
because it is sequential access instead of random access.
An Audio CD-ROM consists of one or more tracks of raw uncompressed
audio data. Each track contains a digital representation of analog music,
consisting of a digital sampling of music at a certain bit rate (128000
bits per second (128 kbps)) and certain sample rate (44100 samples per
second (44100 Hz)). An Audio CD-ROM can hold up to 74 minutes of music.
Audio CD-ROMs are not re-writeable. Characteristics of audio CD-ROMs are:
Digital -- the analog wave of music has been "chopped up"
into many frames. This is similar to the individual frames of a
motion picture, except that the number of frames per second (the sample rate)
is much higher. The frequency and amplitude of each frame is
converted into a series of bits. These bits are then saved and used instead
of the analog wave.
Somewhat sequential access -- you can easily jump
to a specific music track on an Audio CD-ROM, but in general,
you cannot jump to a specific place within that track.
A Mini-Disc (MD) is like a small CD-ROM, except that the
audio files on an MD use a Sony proprietary format (ATRAC) to
compress the files by a factor of five. Mini-Discs are re-writeable.
A Mini-Disc can hold about 74 minutes of stereo digital data, or twice
that amount for mono. Characteristics of Mini-Discs are:
Many callers use Mini-Discs when calling. The player and discs are
small and can easily be carried around. Many MD players have an automatic
loop feature that can be used with a patter record
-- to use, record the song, then use the Mini-Disc's track marking functions
to divide the song into three tracks (the introduction,
the main part, and the trailing tag). Start the song by playing the
introduction track. When the introduction finishes the player automatically starts
playing the main track. At this point, press the auto-repeat button and
when the player reaches the end of the main track it will loop back to the beginning
of the main track and replay the song again and again until the auto-repeat button is turned off,
in which case when the main track finishes, the trailing tag track will automatically be played.
Digital, somewhat sequential access -- same characteristics
as a CD-ROM.
An MP3 File is a digital music data file that has been
compressed according to the MPEG-1 Audio Layer III international standard.
MP3 compresses a file by about a factor of ten. MP3 files may be played
on a laptop computer, an MP3 player (like a CD player), or some other
digital device (such as a Palm Pilot). Characteristics of MP3 files are:
Software compresses an MP3 file in two steps:
Digital, random access -- using an MP3 player on a computer,
you can easily jump to a specific music location.
Sounds that are "imperceptible" by the human ear are dropped or combined
with adjacent sounds. This includes sounds that are too close together
in frequency, duration, or volume. Because data is lost with this step,
an MP3 compression is known as a lossy compression.
A traditional "Zip"-style (lossless) compression is done.
|How to Obtain Digital Music|
Purchase and download MP3 files from these sites on the web
Square dance music
All kinds of music
Make your own MP3 files (more about this later)
- from records -- use a program such as Cool Edit 2000.
- from CDs -- use a program such as AudioGrabber.
Use a music generation program to create your own music.
As far as copyright issues go, digital music is just like any other music --
legally you must have purchased a copy of the music to use it.
|Advantages and Disadvantages of Using MP3|
You can use non-square dance music
If you find a good instrumental piece of music, you
may be able to modify it and use it for square dancing.
I've found several good selections
from my Boogie-Woogie and Dixieland Jazz CDs. In some cases, I've changed
the tempo to about 128 beats per minute to make the music suitable
for square dancing.
MP3 significantly reduces the size of the digital data.
The resultant MP3 file is compressed by about a factor
of ten from the original wave (WAV) file.
The MP3 compression technique is lossy, which means that data is
lost during the compression technique. When the file is uncompressed,
it will not be an exact copy of the original (WAV) file. This is only
an issue if you edit the MP3 file.
When you edit an MP3 file, you lose fidelity (i.e., sound quality).
This is because the edit process involves uncompressing the file
into WAV format, performing the edits on the WAV file, and then recompressing
the data into MP3 format. Because the data has now been compressed twice
(once to create the initial MP3 file, and once to
create the new MP3 file from the edited WAV file), it has gone through
the process of dropping information twice, which may cause a noticeable
loss of fidelity. Editing an MP3 file is like making a copy of a copy
of a tape -- each time a subsequent copy is made, more fidelity is lost.
|How to Convert a 45 RPM Record to MP3|
Rip the music to the computer then encode it.
Many programs are available to do these functions, and some are free.
Often the process of ripping and encoding is combined into a single step.
I use Cool Edit 2000 (described in a later section).
Ripping is the process of extracting
WAV data from a CD, a record, or other music source. That is, ripping
is getting the music data into the computer.
Encoding is the process of converting
the music data from WAV format into the compressed MP3 format.
|How to Convert an Audio CD to MP3|
Use a CD-ripper program such as AudioGrabber (described in a later section).
|My Perspective on MP3|
I am a Software Systems Engineer, so
the decision to use a computer and MP3 files was easy.
I've been exclusively using MP3 files for my calling for more than
I have a total of 1535 square dance records converted into MP3 format.
All 1535 are currently available on my laptop. It's quite convenient to
have such a large selection of music always available to choose from (when
dancers come up and ask "do you have the such-and-such record that you used
last year when you were here?", the answer
is always "yes"; when calling with another caller it's easier to find a
tune that you both agree upon; etc.)
A laptop computer to play the music; display choreography and/or lists
of calls; etc.
A Music Player program. Many music players are available
for free on the web. I use
- Winamp (free) (described in a later section)
- Microsoft Media Player (free, part of Internet Explorer)
An amplifier such as Hilton MA-150 -- it's small and compact.
Microphone, cords, speaker(s)
|Advantages and Disadvantages of Using a Laptop Computer|
Lots of storage space.
One gigabyte of storage can hold about 600 square dance MP3 files. An
average MP3 file for a square dance tune (recorded in mono) is about 1.7KB.
A laptop with a 32GB hard drive should easily hold over 15000 tunes.
CD-ROMs -- a computer can also play music from a CD-ROM.
An Audio CD-ROM can hold about 19 square dance tunes.
A Data CD-ROM can hold about 380 square dance MP3 files or about
33 square dance WAV files.
The difference between audio and data CD-ROMS is that an audio CD-ROM is
limited to 74 minutes of music, whereas a data CD-ROM is limited
to 640 MB.
An audio CD-ROM can be played in any CD player, whereas a data CD-ROM can
only be played on a computer or a special MP3 player.
Music files can be organized into a database, into a playlist, or simply
be placed into a standard computer folder.
A database is a list of music files, along with any other information
associated with the music files (e.g., title, label, label number,
artist, type of music, rating, beats per minute, cue sheet, lyrics,
A playlist is a list of music files. A playlist is usually just
another file stored on your computer that a music player uses
like a database to keep track of a set of music.
Playlists and databases make it easier to locate specific
selections of music. You can sort or search for music by title,
label, type of music, etc.
Music files should be named so as to reflect their contents. This makes
the files easier to find, organize, and determine their contents just by
looking at the filename. For example,
- Miss Frenchy Brown on Grenn 17016.mp3
A laptop computer can also be used to display cue sheets or lyrics,
a tip timer, a list of calls taught, and choreographic sequences.
You must be computer-savvy -- if something goes wrong with your computer,
you need a clue about what to do.
For example, what if your computer crashes irretrievably?
Do you carry backup records and a turntable, or do you carry
backup CDs and hope to borrow a laptop from someone at the dance?
A little more setup is involved -- you need to boot the computer (which
may take a few minutes), and connect the necessary cords.
There is a learning curve for both hardware and software.
You may need to use trial and error to configure your system --
you may need to try different cords, different software,
different settings, etc.
|Selecting a laptop|
Almost any new laptop purchased today should work just fine for playing
MP3 files. Speed, brand, or memory are not major considerations.
You might look for a "multimedia" laptop because it may have a better
sound card than a non-multimedia laptop.
The most limiting factor to using a laptop for calling is hard disk space.
As your collection of MP3 files grows, you will eventually use a lot of
disk space. Choose a laptop with plenty of hard disk space -- more
is definitely better in this case.
If you plan on viewing choreography or other information on the
laptop while you're calling, get a laptop with a large screen.
My original laptop is a Dell Inspiron 3200. It has 96MB memory, 4.7GB Hard
Drive, and runs at 266MHz. I've used almost all of the available hard disk
space on it. It contains 926 square dance MP3 files, and I still occasionally
call with it.
My new laptop (as of December 2000) is a Dell Latitude C800, which was
the top of the line professional model when it was purchased. It has
256MB memory, a 32GB Hard Drive, and runs at 850MHz. It also has a large
screen size, which I really like.
Hundreds of software products are available. Here are the ones that I use
and where you can get them on-line:
Cool Edit 2000 http://www.syntrillium.com/
- Cost: $69
- How to use
Rip -- record the music from the turntable into the computer.
Normalize -- adjust the volume level of the recorded music to a preset,
maximized, level. This step ensures that all of your music files are at
the same volume level.
Edit -- Reduce noise, change tempo, change pitch, trim blank space from
the beginning or ending, remove the introduction, apply sound filters,
Encode & Save -- save the music as an MP3 file.
Play Music -- Cool Edit 2000 is also a music player.
Cool Edit 2000 does not have the functionality to rip from CD-ROMs
-- use AudioGrabber (described later).
Before encoding into MP3, you many want to save the WAV file for backup purposes
in case you wish to edit the music in the future. I write WAV files to
CD-ROMs for storage so I don't use up all the space on my hard drive.
- Cost: Free (download from the Winamp web site)
Winamp has many "skins" (personalized appearances), and many
"plug-ins" (add-on software for special effects, changing pitch, tempo,
How to use
- Play music
- Organize files into a playlist
- Cost: $20.
AudioGrabber is a CD-Ripper program. It reads an audio CD in your
computer's CD drive, and creates a WAV (or MP3) file for each selected track.
AudioGrabber is extremely easy to use.
- Cost: $200.
Music database, automatic looping (record reset), break/tip
timer, write and display choreographic sequences, cue sheets, etc.
CSDS controls the Winamp 2.x or the Microsoft Windows Media Player.
CSDS is a program written for square dance callers by a square dance caller
|Other Thoughts on Digital Music|
ID3 tags -- allows extra information to be placed in the MP3 file (e.g.,
artist, title, copyright, thumbnail image, comments, etc.)
Portable MP3 players -- these are like CD players. Some play MP3 CDs, others
allow you to download MP3 files from your computer. Palm Computers may
also be able to play MP3 files.
Making a CD -- with a CD-W or CD-RW drive, you can create your own CDs.
Mono vs. Stereo. -- most square dance records are recorded in mono (one
channel). Most standard square dance sound systems are also mono. Recording
an MP3 file in stereo takes twice as much space (an average of 3.4MB instead