Audio CDs confuse many people and Windows – trying to be helpful, of course
– doesn’t help.
The fact is that an audio CD is a very different beast from a data CD.
Windows may try to make an audio CD “look like” a data CD by listing its
contents as one .cda file per track, but in reality, it’s just fooling
Those “files” aren’t really there.
Many people think that if they could just convert their .mp3 or other audio
files into that .cda file format, they can just write them to the disc and
they’d have an audio CD disc that would play in any player.
It just doesn’t work that way.
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Audio versus data
A data CD is very much like a hard disk. It contains sectors and files and folders and directories and all the things that we’re used to seeing on a hard disk.
In fact, the CD is written very much like a set of concentric circles of data,
just as hard disks are.
An audio CD has none of that.
however, you need to do things a little differently.”
An audio CD is more similar to an old vinyl record; it’s best thought of as
a single spiral of data – in the reverse of that vinyl – starts in the
center and slowly spirals outward. A single stream of bits.
While a data CD can contain music, it’s often in the form of compressed .mp3
files or files of other audio formats. The result can be several hours of music
in the roughly 700 megabytes that can be stored on a CD.
Not so for an audio CD. That single spiral of data can contain only one
format: uncompressed 16-bit stereo audio at a sampling rate of
44 kilohertz. If you do the math (16 bits per sample times two stereo tracks times
44,000 samples per second, then divide that by 8 bits per byte), you find that
an audio CD requires 176,000 bytes per second of audio and a 700-megabyte CD
can hold approximately 69 minutes of audio1. That’s it.
What further confuses matters of course are audio CD players that can
also play data CDs. These normally have an MP3 logo somewhere on them.
For these players, you can simply burn your mp3 files to a data CD and enjoy
hours of music.
If your CD player can only play true audio CDs, however, you need to do
things a little differently.
Start with ImgBurn
I’m going to use my favorite free CD and DVD burning utility, ImgBurn, to burn
an audio CD of one of my podcasts.
Important: When visiting the ImgBurn site, ignore all of the
recommended downloads or the “Before you download” statements that you see. Those
are all advertisements and are not required. Click Download in the upper left of the site and then click on any of the listed mirror sites to download ImgBurn and only ImgBurn. And like any download, make sure to pay close attention to all options, taking the Advanced or Custom path and
declining any additional toolbars or other offers.
It all starts with CUE
Run ImgBurn and select Write image file to disc:
If you’re not using the easy mode picker, simply click on
Mode followed by Write.
Now click on the “Create CUE File…” button:
In the resulting dialog, click on the Browse for a file… icon:
In the resulting dialog, locate and select the .mp3 files2 you want to write to your audio CD.
Remember that the total time of the audio cannot exceed the capacity of an
audio CD: a little over an hour.
In the example above, I’ve multi-selected (holding down the CTRL key as I
clicked on each file) two of my recent answercasts in .mp3 format to be written
to an audio CD.
Once you click Open, ImgBurn spends a couple of seconds
analyzing the files.
Now, click on the “Session” line in the resulting list:
You can see that in the CD-TEXT section below, I’ve selected
Custom and entered in information relating to the CD.
You can actually include CD-TEXT information for each track, if you like. If
the original file had this information in it already, then ImgBurn may have
pre-loaded these fields as well. Some audio CD players have the ability to
display the CD-TEXT as the CD is played.
Click OK when you’re done editing any CD-TEXT; you’ll be
prompted to save the “.cue” file. I’ll save mine as
ImgBurn then returns to the “Write” display with that file ready to be
Burning the disc
Insert your blank CD-R. I do not recommend CD-RW media and in fact, I
recommend a good quality CD-R at that. Not all audio-CD players will play
write-able material properly, even when written in the correct format. Using
CD-R and quality media stacks the deck in favor of producing a CD that can be
played in most players.
After you’ve inserted the media, the burn button un-grays:
ImgBurn burns the audio CD.
Once complete, you’ll have a CD in audio format.
A CD that Windows once again will fool you into thinking contains files.
But now, you know better and can create your audio CDs the proper way.
1: Not only have I rounded to make the math just a little clearer, but the
capacities of CDs can vary some as can the ability of CD writers and players
to write full capacity. As a rough rule of thumb, it’s safest to say that an
audio CD can contain just over an hour of music. More or less.
2: ImgBurn will actually support a wide variety of file formats. Click on
the All Supported Files drop-down in the selection dialog box for a