Intervals
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- Published on Saturday, 07 April 2012 17:13
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Intervals - By guitarelements
"Interval" refers to the distance between two notes. We label intervals in two ways.
We give the interval a numerical value (a quantity) such as a 4th or a 5th, which is determined by the number of steps it is from one note to another.
If you were asked to name the interval between a C and the A above it you would simply count up the notes. Note that the first note must be counted as '1'.
So the interval between C and A is a sixth.
Next we have to label the quality of the interval. Intervals can be referred to as being unison, perfect, major, minor, diminished and augmented.
The interval qualities change when notes are lowered or raised by a semitone.
Intervals can be played both melodically (one note followed by the other), and harmonically (both notes played at the same time).
Many people tend to find identifying melodic intervals somewhat easier since each note of the interval is played individually.
If the interval is played harmonically it is important that you can sing both notes of the interval before trying to identify it.
Once you can sing both notes of the interval, there are several methods which are often used to help with the recognition of intervals :
- Singing up or down a scale to find the 2 notes of the interval
- Sing the opening of famous or popular songs. Simply find songs that begin with each of the intervals - when you hear an interval, you will make the connection between the interval and the song,
allowing you to correctly identify it!
The distance between 2 consecutive pitches can be referred to as a half step/semitone or wholestep/tone. A whole step consists of two half steps.
Below you can see part of piano keyboard with the half steps/semitones and wholesteps/tones marked.
Major scale, the pitches that are unison, a fourth, a fifth, or an octave above the tonic, are considered to be "perfect" intervals.
This example shows a C major scale with the 1st (unison), 4th, 5th and 8th (octave) degrees highlighted.
Here are the perfect intervals formed from each of these degrees.
Intervals can be played both harmonically (where both notes are played at the same time) and melodically (where one note is followed by the next).
Perfect unison refers to an interval consisting of two notes of the same pitch.
The perfect fourth is five semitones in width and can often have a quite open, neutral sound similar to a Perfect 5th (since they are simply inversions of each other - see Inverting Intervals).
The perfect fifth is seven semitones wide. It can have quite an open, neutral quality.
The perfect octave has a rather neutral sound. Needless to say, the note names are the same, but the pitches are separated by an octave.
The perfect octave is twelve semitones wide.
In any major scale, scale degrees 2, 3, 6 and 7 form major intervals above the tonic.
So in the scale of C major, the notes D, E, A and B are all a major interval above C. (F and G are perfect intervals, the fourth and fifth respectively.)
Here are the major intervals formed from each of these degrees.
The major 2nd is two semitones, or one tone in width. You can recognise this interval by singing up a major scale.
The major third is four semitones wide and can be thought of as having a bright, happy ring.
The colour of a melody in a major key comes largely from the sound of the major 3rd, as opposed to the darker sound of the minor 3rd.
The major sixth can be thought of as having a bright and warm quality, and is quite often found in a melodic context going from the 5th of a major key to the 3rd above.
The major 7th is only a half step or semitone smaller than an octave interval. The major seventh, can feel asthough it wants to resolve to the tonic (a semitone above!).
When the notes are played together, the resulting chord can be considered as having a dissonant or unresolved quality.
Minor intervals are one half step or semitone smaller than major intervals.
For example, the note D is a major 2nd above C, whilst D flat (one half step or semitone below D) is a minor 2nd above C.
Minor intervals occur in a natural minor scale between the tonic and the 3rd, 6th and 7th degrees.
This example shows an A natural minor scale with the tonic, 3rd, 6th and 7th degrees highlighted.
Here are the minor intervals formed from each of these degrees
The minor second is one semitone in width. It can have quite a dissonant sound since the pitches are so close together.
The minor third is 3 semitones in width and is often considered to have a dark, sad sound when compared to a major 3rd.
The minor sixth is 8 semitones wide, and is often considered to have a dark, sad sound when compared to a major 6th.
This is of course dependant upon the musical context. In a major key, the interval from the 3rd degree (ascending) to the tonic forms the interval of a minor 6th. "third and fourth notes" which has a bright, happy sound.
The minor 7th is only a whole step or tone smaller than an octave interval. It can be recognised by singing up a dominant seventh chord. ie a dominant triad based on C would be C-E-G-Bb
Diminished intervals occur when minor or perfect intervals are lowered or "flattened" by a half step or semitone.
The diminished 5th has a fairly distinct sound that some consider to have a slightly dissonant or unresolved quality, although this is largely dependant upon the context in which it is used.
It is 6 half-steps in width and is also know as a tritone, meaning 3 tones or whole steps. It is also aurally the same as an augmented 4th interval.
Augmented intervals occur when major or perfect intervals are raised by a half step or semitone.
The augmented fourth has a fairly distinct sound that some consider to have a slightly dissonant or unresolved quality, although this is largely dependant upon the the context in which it is used.
It is 6 half-steps in width and is also know as a tritone, meaning 3 tones or whole steps. It is also aurally the same as a diminished 5th interval.
Compound intervals are the same as simple intervals but with the addition of an octave.
By adding 7 to the size of any simple intervals, we can find out what the compound interval size would be.
Example: The compound form of a Major 2nd is a Major 9th (2 + 7 = 9) Note that the quality of the interval doesn't change for any quality type.
In the same way, we can find the simple form of any compound interval by subtracting 7.
For example, a Major 13th becomes a Major 6th (13 - 7 = 6).
To invert a simple interval, take the lower of the two notes and place it an octave higher or take the higher of the two notes and place it an octave lower.
By doing this, both the size and the quality of the interval will change.
To work out the new size of an interval, subtract the size of the original interval from nine.
Eg. A 5th when inverted will become a 4th (9 - 5 = 4)
To figure out the new quality of an inverted interval, you must remember the following.
When Inverted:
- Perfect Intervals stay as Perfect Intervals
- Major Intervals become Minor Intervals
- Minor Intervals become Major Intervals
- Diminished Intervals become Augmented Intervals
- Augmented Intervals become Diminished Intervals
When inverting compound intervals, take the higher of the 2 pitches and place it an octave lower, or take the lower of the 2 pitches and place it an octave higher.
In doing this, you are essentially just simplifying the interval ie changing it from its compound form to its simple form.
When inverting compound intervals, the quality of the interval does not change, and the size of the inverted interval can be calculated by subtracting 7 from the compound interval.
For example, the inversion of a Major 13th is a Major 6th (13 - 7 = 6).
