Piano: Intervals: An Open Learning Guide

As we mentioned before, the piano illustrates the basis for musical theory. This chapter discusses intervals in theory and shows the relationships between them. It also will give you a better understanding of how intervals can be used to derive remaining parts of chords you don't know. We will further discuss chords in a different section, but this will be a basic introduction in chord building, and will show you how you can accompany different songs while you play melodies with your right hand. In this section, things might begin to get really, really confusing, especially if you don't have any kind of previous music theory knowledge. Take your time, relax, and if any questions or ideas for improvements to this chapter arise just leave comments on the talk page. I will do my best to explain the concepts to you. It might be a good idea if you have already familiarized yourself with the scales, as i will be using them extensively during this chapter.

An interval can be briefly described as the distance between two notes. For example, in the C major (Ionian) scale, the first and third finger when pressed at the same time form an interval (a major third). Note that notes in intervals can be separate and in order: ascending (c, e) and descending (e, c), or simultaneous (both notes played at the same time). Also note that intervals are characterized by the grades of the scale, taking each note of a scale and assigning it a number. Intervals are the basis to form chords.

When calculating the distance between two notes, you must be really careful and count the semitones, which, on the piano, means both white and black keys. For example, after c comes c#, then d, then d#, etc. On the piano, the black keys represent semitones that are ignored (not played) when making a third major interval on the c scale. You can play the entire C major scale on just the white keys.

The reason why these intervals are together in this section is because their theoretical explanation is exactly the same, and they work in the same way; the 4th, 5th and 8th intervals work differently.

Play a C and an E. If there are exactly 3 notes (3 black and white keys), without counting the initial and last note, in between them, the interval is called a third major. If there are two notes in between, the interval is called a third minor. The same concept applies to second minor and major. A second minor in the C scale is C and D-flat (no semitones are separating the notes). These second intervals, which, as seen later on, are used for improvisation techniques, are usually played separately and often quickly, and are repeated in ascending order. This method works only for second and third intervals from any given key. Note: Play these notes always in ascending order. The reason for this is that intervals change depending on the order sometimes. This will be discussed further on this chapter.

Although the method for counting notes described above starts to become really ineffective especially on greater intervals, many musicians prefer to sing the notes of the scale with numbers from 1 to 8 to identify the kind of interval that is played simultaneously by ear. If you count up to 3 notes for example, (C to E) the interval is quickly identified as a third major. If we approach a different method and lower the third note of the major scale (from E to Eb) the interval is minor. This is mainly why you need to know the major and minor scales by heart in order to play or identify given intervals. Scale recognition by ear is heavily based on the intervals that you hear, depending on the scales. I will be using this method for better clarity and understanding.

Taking of course the 1st and 6th grades of the A major scale, we can say that A and F# is a 6th interval. If we lower the F# to an F, it becomes a 6th minor. Same applies to the seventh interval: Taking the 1st and 6th grades of the D major scale, we can lower the C# and make the 7th interval a minor one.

Taking the 1st grades of the F major scale, we can have a 5th interval by playing F and C. This is denominated as a perfect 5th. If C is lowered to B, the interval is known as a diminished 5th or tritone; if C is shifted to C#, the interval is known as an augmented 5th. If we take the 1st and 4th grades of the G major scale, we would obtain a perfect 4th interval once G and C are played. Shifting C to C# would result in an augmented 4th; lowering C to B would result in a diminished 4th.

Octaves are also said to be perfect or fixed, because the same note is played at a higher octave. The simultaneous playing of an octave is known as a doubled note. Play the middle C on the piano keyboard, then play the next C that you find either to the right or left of the middle C. Notice how the note sounds the same, or has the same feeling, but it sounds higher. Well, that is because it's the same note, just an octave above (to the right) or below (to the left).

Although it is not really necessary to review this, it helps to clear and avoid any confusion you might have. Remember the perfect 4th interval we had mentioned before? Well, you can find out that if we lower the C and play the notes G and B, we obtain a third major interval. Same when shifting the note: We obtain an augmented 4th interval or a diminished 5th interval. For the 2nd and 3rd interval relationships, a 3rd minor interval is also an augmented 2nd interval, and a 2nd major interval is a diminished third interval. This relationship also works with 6th and 7th intervals, and even with octaves, if you stop and think about. Now that we have discussed the intervals at length, let's make some decisions here.

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Text adapted from Piano/Intervals by Wikibooks contributors under CC BY-SA 4.0. Paragraphs have been selected and abridged, and formatting adjusted. This adapted text is shared under the same licence. Contributor history.