ABC Files
ABC files are standard text files. They may have a .txt extension but for ABC software to recognize them it is best use the .abc extension. An ABC file may contain a single tune or a collection of tunes in a single file called a "tunebook." An ABC file is composed of at least two sections. The first part is the header which contains some necessary information such the name of the tune, the meter and the key, and may contain a considerable amount of other information. The next part is body, containing the notes making up the tune, including the pitch and duration of each note.
THE ABC HEADER
Every ABC file has a header. Some fields are necessary and some are optional. Let's dissect a header. Each header item is a letter (case sensitive) followed by a colon and some important information. There are many more optional header fields that I will leave you to explore on your own!
X:1
T:Finnegan's Wake
M:4/4
L:1/8
Q:1/4=225
K:C
X: is the tune's index or reference number.
T: is the title of the tune.
M: is meter of the tune
L: is the length of the basic unit for all notation of duration.
Q: well, I don't know why it is Q, maybe "quickness"! But the Q value is the tempo, how fast or slow the tune should be played. Here since this is in 4/4 time, the 225 represents beats per minute.
K: is the key of the tune.
METER
In sheet music, the meter is the first thing following the clef, and has two numbers. The first is the number of beats in a measure, and the second is the duration of one beat. So, 3/4 meter means there are three beats in a measure and a quarter note is one beat - this is the meter for waltzes. 4/4 means there are four beats in a measure and a quarter note gets one beat - this is the most common meter for many types of tunes. 6/8 means there are six beats in a measure and an eighth note gets one beat - this is the meter for jigs!
LENGTH
As we said, all sheet music shows, at a minimum the pitch and the duration of a note. In ABC, duration is shown as a multiplier or divisor following the note's pitch. The L: value sets the default unit of length. If L:1/8, then a note with no multiplier or divisor is an 1/8 note. A note such as A2 (multiplier of 2) is a quarter note. A note such as A/2 (divisor of 2) is a 1/16th note.
KEY
The K: header item tells us (and tells our software!) the key of a tune. The name of the key, such as C, D, E or F, indicates the starting note of the scale (the "tonic"). The starting note tells us (and the software!) what sharps or flats are in the scale for the key. In sheet music, the key signature immediately follows the meter. A major scale has defined intervals, a full step between each note except for half steps between the third and fourth notes and the seventh and eigth note (the beginning of the next octave). The key signature tells us what notes are sharp or flat in that key. The key of C major has no sharps or flats, the key of D major has two sharps (F# and C#), the key of F major has one flat (Fb), and the key of G major has one sharp (F#), and so on. Minor keys can be entered in the K: field as well as other modes, such as Dorian or Mixolydian. C, Am, Ddor, Gmix all have no sharps or flats. Try playing the scale with no sharps or flats starting on each of these notes to see what each one sounds like!
ABC files are standard text files. They may have a .txt extension but for ABC software to recognize them it is best use the .abc extension. An ABC file may contain a single tune or a collection of tunes in a single file called a "tunebook." An ABC file is composed of at least two sections. The first part is the header which contains some necessary information such the name of the tune, the meter and the key, and may contain a considerable amount of other information. The next part is body, containing the notes making up the tune, including the pitch and duration of each note.
THE ABC HEADER
Every ABC file has a header. Some fields are necessary and some are optional. Let's dissect a header. Each header item is a letter (case sensitive) followed by a colon and some important information. There are many more optional header fields that I will leave you to explore on your own!
X:1
T:Finnegan's Wake
M:4/4
L:1/8
Q:1/4=225
K:C
X: is the tune's index or reference number.
T: is the title of the tune.
M: is meter of the tune
L: is the length of the basic unit for all notation of duration.
Q: well, I don't know why it is Q, maybe "quickness"! But the Q value is the tempo, how fast or slow the tune should be played. Here since this is in 4/4 time, the 225 represents beats per minute.
K: is the key of the tune.
METER
In sheet music, the meter is the first thing following the clef, and has two numbers. The first is the number of beats in a measure, and the second is the duration of one beat. So, 3/4 meter means there are three beats in a measure and a quarter note is one beat - this is the meter for waltzes. 4/4 means there are four beats in a measure and a quarter note gets one beat - this is the most common meter for many types of tunes. 6/8 means there are six beats in a measure and an eighth note gets one beat - this is the meter for jigs!
LENGTH
As we said, all sheet music shows, at a minimum the pitch and the duration of a note. In ABC, duration is shown as a multiplier or divisor following the note's pitch. The L: value sets the default unit of length. If L:1/8, then a note with no multiplier or divisor is an 1/8 note. A note such as A2 (multiplier of 2) is a quarter note. A note such as A/2 (divisor of 2) is a 1/16th note.
KEY
The K: header item tells us (and tells our software!) the key of a tune. The name of the key, such as C, D, E or F, indicates the starting note of the scale (the "tonic"). The starting note tells us (and the software!) what sharps or flats are in the scale for the key. In sheet music, the key signature immediately follows the meter. A major scale has defined intervals, a full step between each note except for half steps between the third and fourth notes and the seventh and eigth note (the beginning of the next octave). The key signature tells us what notes are sharp or flat in that key. The key of C major has no sharps or flats, the key of D major has two sharps (F# and C#), the key of F major has one flat (Fb), and the key of G major has one sharp (F#), and so on. Minor keys can be entered in the K: field as well as other modes, such as Dorian or Mixolydian. C, Am, Ddor, Gmix all have no sharps or flats. Try playing the scale with no sharps or flats starting on each of these notes to see what each one sounds like!
