Why is the sixth sometimes considered a dissonance which needs preparation?

1. Is a sixth dissonant?
2. What is a prepared dissonance?
3. What causes dissonance in music?
4. Why do some intervals sound dissonant?

Is a sixth dissonant?

The major second, third and sixth, as well as the minor third, sixth and seventh are considered to be imperfect consonances. The perfect fourth is dissonant in some contexts but consonant in others (see below).

What is a prepared dissonance?

In tonal music, a preparation is the consonant pitch or chord which precedes a dissonant nonharmonic tone. The move from a dissonance to a consonance constitutes a resolution.

What causes dissonance in music?

Dissonance is caused by the beating between close but non-aligned harmonics. Dissonance may be the difficulty in determining the relationship between two frequencies, determined by their relative wavelengths.

Why do some intervals sound dissonant?

If the two notes are dissonant because their frequencies overlap instead of blending together, they create an uneven (offbeat) vibration inside our ear and the brain feels unsettled.