In simplified musical notation, adding a horizontal line under a note means that the sound has been reduced by half the time value, that is, the note is half a beat; adding two horizontal lines means that the sound has been reduced by half the time value and then reduced by half the time value. , that is, the note is a quarter beat.

The horizontal line under the note is called the minus time line, which means that the time value of the note is reduced by half. The more subtractive time lines there are, the shorter the note is. Each additional subtractive time line means it is shortened to half the length of the original note.

Duration is the length of each note when playing or singing. It is calculated using "beats". When you ask what the duration of a note is, you are asking how many beats the note is played. Use a horizontal line "-" to mark the note to the right or below to define the length of the note.

Extended information:

The combination of sounds of different lengths produces the rhythm and beat of music, which is called the skeleton of the melody. Therefore, the length of the sound is very important in music. When singing and playing music, you must master the timing of good notes.

The positions of the horizontal lines in the musical notation are different, and the durations of the marked notes are also different. The horizontal line under the note is called the minus time line, and the corresponding short horizontal line written on the right side of the basic note is called the time addition line, which means extending one beat. The more time lines there are, the longer the duration of the sound.

To extend the duration of the note, add a horizontal line "-" to the right of the note. The horizontal line at this time is called a delay line. The more delay lines, the longer the duration (duration) of the note. . On the contrary, the more horizontal lines under a note, the shorter the time of that note.

Reference material: Baidu Encyclopedia - Simplified musical notation