Just write down a formula: one, four, five, eight, there is no big or small, two, three, six, seven, there is no purity.

In other words, there are pure intervals in the first, fourth, fifth, and octave intervals, but there are no major and minor intervals; the second, third, sixth, and seventh intervals are Several musical intervals have major and minor intervals, but there are no pure intervals. Augmented intervals and diminished intervals exist for any interval.

In addition, the method of judging polyphonic intervals is to reduce the polyphonic intervals by several octaves and turn them into single intervals before judging. For example: the interval c1-d2 is a ninth interval, which is not mentioned in the above formula, so subtract one octave from this interval and become c1-d1, which is the second interval, so we can know the ninth interval and the second interval Likewise, there are major intervals and minor intervals, but there are no pure intervals.

Extended information:

Tone level whole tone

Tone level

Each tone in the musical sound system is called a tone level. Like 1234567 is the basic pitch level. The width of a whole tone and a semitone is twice the relationship, with one whole tone equal to the width of two semitones. As mentioned above, the distance of an octave and the equal temperament of twelve is divided into twelve equal parts. Each part is a semitone, and two semitones are equal to a whole tone.

In equal temperament, the semitone is the smallest unit that makes up music. The distance between the basic tone levels is not even, so twelve semitones constitute a tone sequence with eight basic tone levels. The relationship between the tones of the major scale is whole, half, whole, whole, and half. (In short, except for the semitones between 34 and 7Ⅰ, the other whole tones. The total between 1 and Ⅰ is 12 semitones)

Number of tones

The intervals included The number of whole tones and semitones is called the number of intervals. Intervals are marked with fractions and integers (1/2 is a semitone, 1 is a whole tone).

For example: 3-4 is a semitone and 4-5 is a whole tone

In order to distinguish intervals with the same degree but different numbers of sounds, add pure, major, minor, augmented, and Text descriptions such as subtraction, doubling, and subtraction.

Music degree

The following is the musical interval, and the size of the musical interval is measured in degrees. The most basic musical intervals are the perfect degree and the perfect octave. A pure degree is the same two notes, and there is no distance called a pure degree. Why is a pure octave so basic? As mentioned above, I won’t go into detail here. In many cases, the properties of a pure octave are similar or even the same as those of a pure one.

On the basis of these two intervals, plus the two intervals of perfect fourth and perfect fifth, these are the four basic pure intervals.

Interval attributes

The determination of each interval attribute 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.

For example, the two tones 13 contain three tones of 123, so it can be determined as a third. However, the characterization is not complete at this time. Look at the two tones between 12 and 23. Semitone, so the third of 13 contains three steps and four semitones, which is called a major third.

For another example, 35 contains three tone levels of 345, but there is only one semitone between 34. It contains three tone levels and three semitones, which is called a minor third.

Baidu Encyclopedia--Music Interval

Baidu Encyclopedia--Music System