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Making MP3 Sound Recordings |
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They can be very small
in size, but looks can be deceiving.
These tiny devices can
hold many hundreds - even thousands of hours of music.
This article tells you how to
create the music files that such units need. |
Making MP3 recordings from your
CDs and tapes might seem more complicated than simply copying
them onto a cassette, but once you understand the basic
settings, it becomes very easy indeed.
And these days you no longer
even need to buy special software to convert ('rip') your CDs to
digital format.
Update - 2020
These days MP3 is no longer
a preferred medium for storing digital copies of your music.
There are no longer the constraints in terms of storage and
bandwidth that applied when this article was written in 2002.
If you still encode in MP3, do
so at the highest bandwidth setting (320kb). Otherwise, you
should now use FLAC format, which can also be created through the
dbPowerAmp program recommended below. Please also refer to
our new series on high quality music - here's one possible
entry point into the ongoing series.
MP3 explained
MP3 is a way of compressing
sound files into smaller sizes. Just like jpg compression makes
picture files smaller, so too can MP3 compression make sound
files smaller (than, for example, they are on a regular CD).
MP3 files contain music. MP3
files can also hold considerable information about the piece of
music such as the name of the artist, the song title, and
various other information as well.
MP3 files have become an
industry standard format that most computer music playing
programs can play.
How to Make an MP3 File from a
CD (or other source)
You need a program to
convert the music from the CD or tape or whatever into MP3
format. There are plenty to choose from, and most are quite
inexpensive. Perhaps the best known, and the one I use myself,
is dbPowerAmp. Another popular program is
Easy CD-DA.
Microsoft's Windows Media Player can also do this if you buy a
small add-on to the program.
Simply put a CD in your
CDrom, start up your program (sometimes it will even start
automatically, change a few settings, then hit the record
button. Easy!
UPDATE :
Microsoft have upgraded the capabilities of their free Windows
Media Player so that it can rip your CDs for you. Although
free, it does an excellent job, and so you no longer need to buy
any extra software at all.
Compression - Something for
Nothing?
The most distinctive thing
about an MP3 file is that it is very much smaller than a regular
CD file - typically only one tenth the size of a CD file. In
other words, the music data has been compressed.
You have a choice of many
different levels of compression. But you don't get something for
nothing - the more compressed the file, the poorer the sound
quality. Choosing the right amount of compression involves a
trade-off between sound quality and file size.
The type of sound quality
that is 'best' for you depends on how discerning a listener you
are, and how you will be listening to the music. If you are
listening to it through a car stereo system, then you don't need
as good a quality as if you are listening to the music through a
set of high end headphones. If you are playing the music back
through a small set of cheap speakers, you again don't need the
same quality as if you are playing it through a $10,000 hi-fi
system.
The Best Compression Compromise
If you are short of file
space and do not care about the music quality too much, compress
at a sampling rate of 128 kb/sec. If you have more space and
want audibly better sounding music, then increase to 160 kb/sec.
If you want to have excellent quality music, almost as good as
on a CD, then use a 192 kb/sec rate.
It is possible to compress
at rates as high as 320kb/sec, but you're really starting to get
into diminishing returns when climbing over 192kb/sec.
This is what is known as
'constant bit rate' (CBR) compression. There is also a different
form of compression called 'variable bit rate' (VBR)
compression. This works on the basis that sometimes music can be
compressed a lot, and sometimes it needs to be much less
compressed to preserve its quality. If you choose VBR, start
with a setting around 50% - the higher the percentage, the
better the quality (and the larger the file size).
You can hear
samples of a short
musical clip recorded at six different sampling rates in the
article on different music file types.
Other Recording Settings
There are several other
important settings that you need to optimize in your program.
The first of these is to set
your program to take digital audio from the CDrom drive, not
analog audio. Look for a setting somewhere in your recording
settings - it might say 'DAE' or 'Digital recording mode'. If
there is an 'error correcting' option, take this, too.
Maybe there is a bandwidth
option - to choose how high the maximum frequency you will
encode is. The human ear, in theory, can hear up to about 20kHz,
but this ability drops off with age. Most speakers do not play
sounds this high in any case. The lower the bandwidth, the
better the quality of the remaining music. I'd suggest setting
somewhere between 15kHz and 18kHz as optimum, and if you have
poor quality speakers, you could even go down as low as 12kHz.
Changing the bandwidth setting does not change the file size.
Maybe your program also has
an option to specify how carefully it compresses the music. This
might be referred to as 'encoding' or 'processing'. The higher
you set this, the better the sound quality will be - without
causing the file size to grow. For that reason, I always set the
processing to 'maximum'. The only trade-off here is that it
really slows down the speed at which a CD is converted to MP3.
How Long Does it Take
The time it takes to convert
a CD to an MP3 depends on your settings - the higher the
processing and the broader the bandwidth, the more computing
your computer has to do.
The time it takes also
depends on your computer speed. For example, I use two computers
to convert CDs - one is a P3-450MHz and the other is a
P4-1.7GHz. The faster computer is about five times faster than
the slower computer at converting files.
With moderately high quality
settings, my fast computer will record at up to eight times the
CD play back speed (in other words, 80 minutes of music take ten
minutes to record and convert). With very high quality settings,
it runs at about 1.9 times play back speed (the 80 minutes now
takes 57 minutes. And, with the same very high quality settings,
my slow computer runs at about 0.3 times playback speed (80
minutes takes 265 minutes to record!).
There might be a way to
speed up your recording time - by updating your CDrom driver.
Usually the CDrom drive uses a generic driver. I used the latest
free version of Real Audio's Real One player and within that
there is an option to download and install a better Adaptec ASPI
driver. Doing this increased my CDrom's speed by about 30%!
Update - 2007 : Faster
computers mean that these days I can rip CDs (convert them) into
digital files at almost 20 times playback speed. A one
hour CD can be converted in three minutes. Amazing!
Naming Files - CDDB
It is very important that
your music files have helpful names that tell you what the music
actually is that you have recorded.
The good news is that this
process can be automated, most of the time, with most recording
programs. The recording program will recognise a unique
identifier for the CD and then will, over the internet, query a
massive database (usually the CDDB database) to find out details
of what the CD is, who the artists are, what the track names
are, etc. This information isn't always 100% accurate, but most
of the time it is nearly 99% accurate. The recording program can
then automatically add this information to the files you create
so that you don't need to type in anything yourself.
Playlists
Maybe you have two or three
CDs that you have recorded. One track is duplicated on a couple
of the CDs, and there are a couple of other tracks that you
don't like, and you would like to change the order of the music,
with a mix of tracks from first one CD then a different CD, and
so on.
This is all easily possible
by creating a playlist. The playlist simply tells the playback
program which files (tracks) to play, and in what order. A
playlist can combine tracks (files) from as many different CDs
as you wish, and in any order you like.
Creating playlists can give
you tremendous flexibility in how you finally play back your
music.
Special Situation - Voice Only
Recordings
If you are recording
'talking books' or other types of voice only conversation, you
can use much more compression. And if the sound source is mono,
not stereo, you can use even more compression. For voice, set
your bandwidth down to maybe 8kHz and use a compression rate of
96kb or even 64kb (if mono).
Related Articles, etc
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Originally published
3 May 2002, last update
20 Jul 2020
You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me as original writer.
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