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Do most music CDs have 12 tracks?

This might sound like some wild conspiracy theory, but I'm looking at my music collection and it sure seems like most of them have exactly 12 tracks, no more, no less. Is there some marketing reason this would be the case, or am I witness to some great conspiracy? :-)

Dave's Answer:

Don't panic! There's no magic to it. A music CD can hold 60-70 minutes of music and the average pop song is about 5 minutes long. Do the math and you'll see that gives you about 12 songs per CD.

But I figured I'd do a bit of math here too. I have about 425 CDs in my music library, a wide range of genres, from country to classical, jazz to blues, and here's what I found:

428 albums analyzed
5369 tracks examined

The results:

Occurrances	Number of Tracks
65	10
56	12
50	11
41	9
25	8
24	15
22	14
17	13
17	7
15	18
15	16
14	1
11	20
9	19
8	6
7	17

That is, 65 of the 428 albums have 10 tracks, 56 have 12 tracks, 50 have 11 tracks, 41 have 9 tracks, and so on. Percentage-wise, this means that less than 15% of my 428 tested CDs have exactly 12 tracks, but averaging everything out, yes, the average music CD has 12.54 tracks.

So there's your answer. No conspiracy theory involved! :-)

How I did these calculations

For those of you who would like to analyze your own iTunes library, here's how I did these calculations. I popped open a Terminal window on my Mac, moved into my "iTunes Music" folder within my "Music" folder, and...

$ find . -type d -mindepth 2 -print | wc -l
428

The predicate "-type d" is directories, so that tells me the number of Cds, and

$ find . -type f -mindepth 2 -print | wc -l
5369

That's the number of individual tracks across all those CDs. This means, by the way, that the average CD in my library, at least, has 12.54 tracks. So maybe there is some sort of conspiracy!

To figure out how many tracks there are per CD is a bit more tricky. To accomplish this, I actually wrote a short shell script:

#!/bin/sh

cd "/Users/taylor/Music/iTunes/iTunes Music"

for directory in $( find . -type d -mindepth 2 -print | sed 's/ /_-_/g' )
do
dirname="$(echo $directory | sed 's/_-_/ /g')"
echo $( ls "$dirname" | wc -l ) tracks: $dirname
# ls "$dirname" | wc -l
done

exit 0

When run it lists tracks and albums:

$ tracks-per-song.sh | head
14 tracks: ./10,000 Maniacs/MTV Unplugged
12 tracks: ./10cc/Greatest Hits 1972-78
10 tracks: ./Acoustic Alchemy/Blue Chip
9 tracks: ./Acoustic Alchemy/Red Dust & Spanish Lace
9 tracks: ./Acoustic Alchemy/Reference Point
12 tracks: ./Adrian Legg/Mrs. Crowe's Blue Waltz
6 tracks: ./Al Di Meola/Elegant Gypsy
9 tracks: ./Al Di Meola, Paco de Lucia & John McLaughlin/The Guitar Trio
11 tracks: ./Al DiMeola/Splendido Hotel
11 tracks: ./Al Jarreau/All I Got

When I comment out the echo line and just output the number of tracks as a number with the wc command, I can easily slip the script into a typical collation sequence:

$ tracks-per-song.sh | sort | uniq -c | sort -rn
65 10
56 12
50 11
41 9
25 8
24 15
etc etc etc

Classic Unix command line stuff! :-)

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Categorized: Shell Script Programming , Unix and Linux Help , d) None of the Above (Article 6682)
Tagged: apple itunes, music cds, shell script programming
Previous: How do I put music on my Apple iPod?
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Comments

Thanks for this one, Dave - it may well help me with a plan I have to make playlists of all the 'singles' I have accumulated over the years.
I've searched through Dougs Scripts http://dougscripts.com/itunes/index.php and can't find anything relating to this - perhaps CD singles weren't as prevalent in the US as they were in the UK.
Anyway, with your script I should be able to get a decent picture of what 'singles' (that is total number of tracks equal to or less than 4) I have ripped so that I can start to build suitable compilation playlists of 'b sides'.
Great site btw, I keep you on my google reader RSS feed and look forward to new content each day!

Posted by: Baz at May 18, 2008 6:37 AM

Can the nr of tracks, for example 46 (aac, so cd language) be a problem for some cd players?.. By what reason? And does -R or +R does ast old players. A same brand -R cd she before received with a 23 tracks cd, labled with #9, and later this of same type -R and brand, labled #1 with 46 tracks; do i need to split. I heard of a pro-blem at 99 tracks.. Apart; an older cd-midiset in a chuch eyed though modern (with needles though) and a portable cd-radio set both did not accept or readed it as 'empty' or 'er'(error).., my laptop pc, my midiset, my portable radio-cd did accept and play splendid the stuff, before and after!! ARE there different planet-worlds ??
I once heard 20, 25 or lateron 32, 33 was once a recognition maximum for players, tilting when higher !? One on internet wrote that replica-cd's there really pressed and more secure work 100% in all media sets, and duplicat - shortrun- are quicker "burned" -in fact 'upbeamed' on dye to dark(en the chemical thin layer with spurs of dots and stripes)-, but shorter live cd-life and lesser reliable and not suited to all players new and older.

Posted by: Werner van der Wal at January 21, 2009 9:01 PM

Thanks for the information. I was Box Car Willie's promotion manager for many years. The USA had nothing to do with him for a very long time. We hit it big in Europe and Australia, then came the good ol' USA.
Again, thannks for the valuable information, as I am working with several new artist, and am encouraging them to put just 10 cuts on their cd...
James Allen
Fort Worth,Texas
jamesallenpromotions@gmail.com

Posted by: James Allen Promotions at June 20, 2009 5:22 AM

find: warning: you have specified the -mindepth option after a non-option argument -type, but options are not positional (-mindepth affects tests specified before it as well as those specified after it). Please specify options before other arguments.

Running Ubuntu 8.04, I get this error while executing bash asdf.sh, with the echo commented, if it's commented it runs perfectly...

Posted by: toor at December 7, 2009 12:35 AM

I have something to say, now that you mention it, but ...

I do have a lot to say, and questions of my own for that matter, but first I'd like to say thank you for all your efforts on this Web site by buying you a cup of coffee!

I do have a comment, now that you mention it!