Music theory is a vast subject. However, when you start getting into the details you begin to see that it's not that hard to understand! In this post we will cover aspects like Intervals, Scales, Chords, Basic Diatonic Harmony and Cadences.
In Music theory, an 'interval' is the difference in pitch between two sounds. Intervals are the basis for the formation of scales and chords.
Check out the table below to get to know the naming system for these intervals. This helps when describing the size of an interval.
Once you know the names of the intervals, it becomes easy to understand how these intervals are used to create various scales and chords.
All scales can be said to have a 'formula' depending upon the gap between each successive note.
Major Scale Formula : 2-2-1-2-2-2-1 (Eg: C D E F G A B C)
Harmonic Minor Scale : 2-1-2-2-1-3-1 (Eg: C D Eb F G Ab B C)
Natural Minor : 2-1-2-2-1-2-2 (Eg: C D Eb F G Ab Bb C)
Melodic Minor : 2-1-2-2-2-2-1 Ascending (Eg: C D Eb F G A B C)
2-2-1-2-2-1-2 Descending (Eg: C Bb Ab G F Eb D C)
Relative Major & Minor :
Every Major Scale has a Relative Minor key and Every Minor Scale has a Relative Major key. For eg: The relative major key of A min is Cmaj and vie versa. These two scales will have the same notes as each other. This holds true for all scales.
The Relative Minor is built on the 6th degree of the Major Scale. This means that if you want to know the relative minor scale for a certain scale, all you have to do is figure out what the 6th degree of the scale would be. Therefore the relative minor of Cmaj is Amin and so on.
The Relative Major is built on the 3rd degree of the Minor Scale. This means that if you want to know the relative minor scale for a certain scale, all you have to do is figure out what the 3rd degree of the scale would be. Therefore the relative major of Amin is Cmaj and so on.
INVERSION OF INTERVALS :
A Major 3rd becomes a Minor 6th when inverted.
- Perfect intervals stay perfect.
- Major become Minor.
- Minor become Major.
- Augmented become Diminished.
- Diminished become Augmented.
HOW WE WRITE CHORDS :
In a Major key, Chords I, IV, V are always Major. ii, iii, vi are Minor, vii is always diminished.
CHORD NUMBER NAME DESCRIPTION
I TONIC MAJOR
ii SUPERTONIC MINOR
iii MEDIANT MINOR
IV SUBDOMINANT MAJOR
V DOMINANT MAJOR
vi SUBMEDIANT MINOR
vii LEADING TONE DIMINISHED
In a Minor key, Chords i, iv, v are always minor, II, III, VI are Major, VII diminished.
4 Part Harmony consists of 4 Voices :
Soprano, Alto, Tenor and Bass
Soprano and Alto are written in the top staff,
Tenor and Bass are written in the bottom.
Stems of Soprrano and Tenor always go up,
Stems of Alto and Bass always go down.
Harmony can be looked at as Chords or as 3-4 separate lines of Music (Singer’s Perspective).
In the case of 4-part Harmony, Singers would sing their part corresponding to Soprano, Alto, Tenor, Bass.
Spacing is important while arranging chords for choir. It’s important to see what note you want to have in the bass.
There should be maximum spacing between the Bass Note and the next note and as we go up in the frequency, the notes can come closer together.
Horizontally there should be minimum gap between Melodic line’s intervals.
PERFECT CADENCE IN 3 PARTS:
The Melodic and Harmonic path chosen at the end of phrase is called a Cadence.
Music comes to rest. Latin “To Fall “.
There are 4 Basic Types of Cadences:
Perfect, Plagal, Imperfect, Interrupted.
PERFECT CADENCE : V - I i.e, Dominant -> Tonic
Most Bass lines take a circuitous path and then end up coming together towards the Cadence.
If you can use only two notes in a Chord, the first and third will give the strongest character of the chord.
If the root note of the Chord is in the Bass, the order of the other notes doesn’t matter, it will still be a Chord in the root position.
If the root note of the Chord changes, it is an ‘Inversion’.
Contrary motion between higher voices and the Bass creates a stronger Cadence.
- Try to move the inner voices to the nearest appropriate Harmony (Chord) Note.
Reason : Big jumps in the individual lines may not sound that good, must make sure that the horizontal lines also flow.
In Harmony it’s important to think of each line horizontally as well as vertically.
Also, augmented 4th are hard to sing so it’s better to keep the upper parts to 2nds/3rds.
The Bass line can jump 5ths but not more than that otherwise it sounds disjointed.
- The Leading Note should rise to the Tonic.
- Avoid Parallel 5ths and octaves between parts even if they are inner voices, because Parallel 5ths and octaves destroy the independence of parts and turns the Harmony into Block Chords.
- Keep the largest gap at the bottom and smallest gap at the top.
CADENCES IN 4 PARTS:
Adding the inner voices => we need to choose which note to double (From the Triad).
This has a big effect on how the Chords sound.
PERFECT CADENCE IN 4 PARTS:
Most people should start by doubling the Root Note.
Try to keep maximum number of common Notes.
Start from the Bass part and work your way up to the outer higher voice and then fill in the inner voices.
Leading Note helps in Chord transition so choose order of the Notes in that way.
VOICES AND DOUBLING:
RANGE: Every Acoustic Instrument or Voice has a limit to how High/Low it can go that is it’s range.
General rule to follow is
1. Keep the largest intervals in the Bass (octave or more)
2. Keep the smallest intervals in the higher parts (6th or less than a 6th)
Get a gap of an octave or more between the Bass and Tenor and gap of less than an octave between Tenor and Alto and also between Alto and Soprano.
Ideally the smallest gap would be between the top two parts but this is not always possible due to other considerations like flowing of horizontal lines / avoiding parallel 5ths and octaves.
If you have a 3-Note Chord and 4 Voices, obviously you need to double one of the notes.
The Note that is doubled will become more prominent since it is played twice.
Better not to double the Leading Note, as this leads to parallel 8ves.
In the first Inversion / Root position, whatever the Chord maybe, it is common double the root note. However, also taking Chord spacing and flow of individual lines into account, it is not always best to simply double the Root Note.
It is best to double the Tonic, followed by the Dominant and leave the 3rd as the last option for doubling.
Another approach is to double whatever is in the Bassline, as this generally works well.
IMPERFECT CADENCES: Imperfect Cadences end up on the Dominant and often go I-V.
Although the Dominant can be approached from a number of Chords, the most common Imperfect Cadence I-V.
Imperfect Cadences are almost always followed by an answering phrase that takes you back to the Tonic.
This is IV – I i.e, Subdominant -> Tonic. It feels less conclusive than the Perfect Cadence but still feels like an end.
FIRST INVERSION AND INTERRUPTED CADENCE
FIRST INVERSION: The 3rd of the Chord is in the Bass, the other Notes can follow any older.
Example: C E G is Cmaj in Root position, E G C s Cmaj in 1st Inversion.
It doesn’t matter which order the Notes are placed on top of the Bass Note.
The important Note that determines which Inversion a Chord is ths Bass Note.
First Inversions are used a lot in 4-Part Harmony.
It gives us added interest to our writing as the Chords have a different sound in the 1st Inversion and also helps in parallel 5ths / 8ves.
If the Bass line is always moving in Root position, it doesn’t have a nice flowy horizontal line. With 1st Inversion Chords it can make the line flow much better.
Parallel 5ths and 8ves destroy the independence of the lines (Makes it feel like Block Chords).
Move in contrary motion.
If all the intervals move in the same direction with the Chord in the same Inversions, you will get lots of parallel Intervals. Hence, use a combination of Chords in Root position and some in 1st Inversion, some in 2nd Inversion – Goal should be to get a smooth flow of independence of parts that move in contrary motion without any large jumps.
Proceeding towards the perfect cadence, but there is unexpected twist.
Usually 5th – 6th but from the 5th (Dominant Chord) it can go to any other Chord (Except Root (1st)
5th b – vi is a common technique. 5th b => 5th in 1st Inversion, vi => vi in root position.
iib – 5th – 1st is also a common technique. (This is for 5th – 1st Cadence – Perfect Cadence)
MORE CHORDS AND INVERSIONS:
2nd Inversion => 5th of the Chord in the Bass.
Example: Cmaj in 2nd Inversion => C 6/4 or 1st C => G E C
1st C – 5th – 1st is a common Perfect Cadence.
I – vi – iib – V – I
2nd Inversion Chords need more delicate handling, i.e Root and 1st Invrsion Chords are easier to get a flowy line.
As in all Inversions, the most common Note to double in the 2nd Inversion is the Note in the Bass but any Note can be doubled.
BASS LINES AND MOVEMENT BETWEEN BASS LINE AND TOP LINE:
Bass lines are important. There are three main possibilities.
1. Bass line moves and Melody is a pedal
2. Melody moves and Bass line is a pedal
3. Contrary motion between Melody and Bass line.
Harmonic Rhythm is what makes the music sound more interesting without it sounding like Block Chords. Also, use of passing notes helps break the monotony.
Bass lines defines Harmony and also the position of Harmony, i.e Root position or Inversion. The relation between Melody and Bass line creates various kinds of effects.
Example: Bass line can be pulsating at double tempo while the Melody moves slowly above it or vice versa. Or you can have Quintuplet Rhythms on the Bass with Melody Notes following a different Rhythm, etc.
Parallel motion should be avoided as it loses independence of parts and everything sounds like one.
OBLIQUE MOTION : Melody stays more or less in the same place where the Bass line rises/falls.
VOICE LEADING: 4-Part Harmony is not just a series of Chords. It needs to be looked at like a grid, horizontally as well as vertically.
OPEN AND CLOSED VOICING:
Open large gaps between Notes of Chords, i.e more Range => Fuller => Closed => Less gaps between Notes of the Chords, i.e less Range => Thinner.
One interesting idea is to move from closed harmony to open harmony as you develop the piece, this makes the piece sound more dynamic.
Voices => Closed Harmony, Strings => Open Harmony