Perfect fourth: A fourth that contains 2 whole steps and 1 semitone is a perfect fourth. do-fa is a pure fourth and fa-si is an augmented fourth.
A musical interval, consisting of four steps and five semitones, is a perfect fourth. The size of musical intervals is measured in degrees. The determination of the attributes of each interval must be judged by two conditions. First, the number of tone series contained in the interval; second, the number of semitones contained in the interval. It contains four pitches and five semitones, which is a perfect fourth.
According to the auditory impression produced by harmonic intervals, intervals can be divided into two categories: consonant and dissonant. Intervals that sound pleasant and blended together are called consonant intervals. More consonant intervals (4th, 5th) and fully consonant intervals (1st, 8th, etc.) are expressed by "pure", while non-consonant intervals (2nd, 3rd, 6th, 7th) are expressed by major and minor degrees.
Extended information
1. Music theory, referred to as "music theory", includes relatively simple basic theories, such as reading music, intervals, chords, rhythm, beats, etc. There are also relatively advanced ones, such as harmony, polyphony, musical form, melody, orchestration, etc. The mastery of music theory has important and positive significance for composing, arranging, conducting, and performing. What we usually call music theory generally refers to the basic part of music theory, that is, "basic music theory".
2. Music theory, also called music theory, is a required course for learning music. What we usually call music theory generally refers to the basic part of music theory, that is, "basic music theory". The problems to be solved are related to the nature of sound, temperament, notation, the basic elements of music, the basic rules of the combination of sounds, etc., and the method of notation (and reading music) is a very important one. part.
3. There are many ways to record music. In ancient China, there were several categories such as Chinese notation and gongchi notation. When used for different musical instruments, there were guqin notation and pipa notation. divided. Similar to writing, music score is a system of symbols prescribed by people. No matter what kind of notation is used, its purpose is to accurately record music so that it can be disseminated and reproduced (performed) based on this record. Staff notation is a modern and internationally accepted notation method. After mastering staff notation, learning simplified musical notation will be very easy.