Music Theory

February 1, 2024

Everything in the universe, including sound, is made up of vibrations. The faster something vibrates, the higher its frequency, measured in Hertz (Hz). When air molecules vibrate, they hit our eardrums, and our brain interprets these vibrations as sound. The frequency we perceive determines the pitch of the sound: higher frequencies correspond to higher pitches, and lower frequencies to lower pitches.

Imagine plucking a guitar string. It doesn't just vibrate at one frequency; it also vibrates at multiples of its fundamental frequency, called harmonics or overtones. These harmonics blend with the fundamental to create the rich timbre of the guitar sound. Interestingly, certain ratios between frequencies create sounds that our ears perceive as pleasant and harmonious.


Around 500 B.C., the Greek philosopher Pythagoras made a groundbreaking discovery. He experimented with strings of different lengths and noticed that strings with specific length ratios produced harmonious sounds. These ratios, like 1:2 (octave), 2:3 (fifth), and 3:4 (fourth), became the foundation of Western music theory.

Here's how it works:

  • Unison (1:1): Two identical frequencies producing the same pitch.
  • Octave (1:2 ratio): When a string is twice shorter, it vibrates twice as fast and produces a sound an octave higher, like C on a piano and the C one octave above it. This resonates because your ear perceives them as similar "colors" of sound.
  • Perfect Fifth (2:3 ratio): Strings with a 2:3 ratio create a pleasing interval known as the fifth. Think of the opening notes of Beethoven's 5th Symphony!
  • Perfect Fourth (3:4 ratio): Similarly, the 3:4 ratio produces the perfect fourth, another important building block of harmony.

These are just a few examples. But these ratios are the basis of harmony. Harmony is when two notes or more notes are played at the same time. Pythagoras found that the more simple the mathematic ratio is between two notes, the more pleasant or consonent was the harmony. But the more complex the ratio is, the more unpleasant or dissonant the harmony is.

The 7 base ratios (diatonic scale)

At first and for a long time, in western music, we had less than the 12 notes we have today. The most simple ratios are:

  • Unison (1:1): Two identical frequencies producing the same pitch.
  • Octave (2:1): Doubling the frequency creates a pitch an octave higher.
  • Perfect Fifth (3:2): A fundamental and essential building block of harmony.
  • Perfect Fourth (4:3): Another cornerstone of consonance, often used in cadences.
  • Major Third (5:4): Creates a bright and joyful sound, essential in major scales.
  • Minor Third (6:5): Evokes feelings of sadness or tension, a key element in minor scales.
  • Perfect Major Second (9:8): Forms the characteristic "whole tone" step.

Some consider the 7:6 ratio to be a "neutral third", neither major nor minor, and it has been used in some experimental and microtonal music compositions. In other countries we can find scales with other kinds of ratios.

These seven ratios were the starting point for constructing scales. But it became limiting to have only 7 notes to play.

The 12 notes (chromatic scale)

The 7 base ratios create the major and minor scales, but additional notes enhance musical flexibility and expression. These notes, called chromatic notes, are achieved by dividing the existing intervals further.

Something we figured out is that if you stack fifth note on top of each other, you end up on the initial note you played. Well almost. The 13th note when you stack 3:2 intervals is not exactly an octave of the initial note. This stacking of fifth notes is called the circle of fifth because we end up on the original note.

After a small correction to each of the 3:2 stacked intervals, we get the following notes:

  • Perfect Unison (Octave): 1:1 or 2:1 or 3:1, etc.
  • Perfect Fifth: 3:2
  • Minor Second: 16:15
  • Minor Sixth: 8:5
  • Major Third: 5:4
  • Minor Seventh: 9:5
  • Major Second: 9:8
  • Major Sixth: 5:3
  • Minor Third: 6:5
  • Tritone (Augmented Fourth or Diminished Fifth): 7:5
  • Major Seventh: 15:8
  • Perfect Fourth: 4:3

This correction is called meantone temperament. We adjust slightly every ratios to have the most perfect ratios on each note. As you can see, the most perfect ratios after unison/octave are the perfect fifth and perfect fourth. The most complex interval is the tritone, also known as the augmented fourth, dimished fifth or the devil's interval because of its dissonance. In meantone temperament we apply a correction to the tritone but in reality the ratio is closer to 45:32 or 64:45.

There are a few problems with the approaches described above.

  1. We want to start on any note of the scale and obtain the same intervals. With meantone temperament, we don't always get the same ratios.
  2. We want to play multiple octaves in harmony without having a difference between them.

To solve these issues, a tuning system called equal temperament was adopted. It divides the octave into 12 equal semitones, each achieved by raising the frequency by the 12th root of 2 (approximately 1.05946). While sacrificing slight harmonic purity, this system allows playing in any key and transposing music easily.

While ratios provide a scientific foundation, music is more than just math. Tuning systems, cultural influences, and even instrument limitations shaped the evolution of our musical soundscape. Remember, understanding ratios enhances appreciation, but the true magic lies in the emotional impact that music creates.

Interval names

Why do we have multiple types of intervals, for example major, minor, perfect, augmented or diminished? Different intervals create different harmonic sounds and functions within a piece of music.

  • Major and minor intervals: These are the building blocks of major and minor scales, which evoke distinct emotional responses. Major intervals sound bright and happy, while minor intervals sound darker and sadder.
  • Perfect intervals: These intervals (unison, octave, perfect fifth, and perfect fourth) are considered the most consonant and stable, often used for creating a sense of resolution or grounding.
  • Augmented and diminished intervals: These intervals are more dissonant and create tension or instability. They can be used for various purposes, like leading to a resolution, adding drama, or creating a certain atmosphere.

Here are all the intervals in order with their respective name and ratios.

Interval Ratio Consonant/Dissonant Unison 1:1 Consonant Minor Second 16:15 Dissonant Major Second 9:8 Consonant Augmented Second 18:16 Dissonant Minor Third 6:5 Dissonant (can be consonant in specific contexts) Major Third 5:4 Consonant Perfect Fourth 4:3 Consonant Augmented Fourth 5:3 Dissonant Diminished Fifth 6:5 Dissonant Perfect Fifth 3:2 Consonant Minor Sixth 8:5 Dissonant (can be consonant in specific contexts) Major Sixth 5:3 Consonant Augmented Sixth 9:5 Dissonant Minor Seventh 16:9 Dissonant Major Seventh 15:8 Dissonant Octave 2:1 Consonant

Notes in western music

Until now we have only talked about intervals, but what about notes. The notes we all know ABCDEFG or do ré mi fa sol la si.

Initially, we only used the most consonant intervals with the 7 notes ABCDEFG. It was limiting musicians to express deeper feelings, tension and resolution but it also limited the number of scales a musician could build from. When we added all the extra notes that make up the circle of fifth, we added new notes in-between other notes. These are called the sharps or the flats and they are the black keys on the piano. There are sharps for the ACDFG notes.

Pitch in western music

For centuries, there was no single pitch standard across Europe. Different regions and traditions used their own tuning systems, leading to variations in the frequency of notes. In France, for example, A was tuned around 435 Hz, while in Italy, it was closer to 440 Hz. This inconsistency posed challenges for musicians traveling and collaborating across regions.

In the 19th century, the need for a unified tuning system grew with the increasing popularity of orchestras and international collaborations. In 1885, the Austrian government proposed A440 Hz as a standard, drawing inspiration from earlier proposals by German physicist Johann Heinrich Scheibler.

While the proposal gained some traction, it wasn't until the 20th century that A440 Hz saw widespread adoption. In 1936, the American Standards Association (ASA) recommended this frequency for the A above middle C, later adopted by the International Organization for Standardization (ISO) in 1975.


In western music, our 12 notes make up what we call the chromatic scale. The chromatic scale is when you go through the all the 12 notes in order. A half step is when you move from one note to the next one (minor second interval), for example A to A# or B to C. A whole step is when you move by 2 notes (major second interval), for example from A to B or from B to C#. The chromatic scale has all 12 notes and moves by half steps.

We use other scales such as the diatonic scale that is made up of 7 notes. It uses a 5+2 pattern where we move by 5 whole steps and 2 half steps. For example he major diatonic scale uses the root, major 2nd, major 3rd, perfect 4th, perfect 5th, major 6th, major 7th. As you can guess the intervals are: whole, whole, half, whole, whole, whole, half. And if we were to start these intervals on a C note, we would get the famous CDEFGAB progression. Now if we started the same progression on a different note such as A, we would get ABC#DEF#G#.

A famous scale in guitar is the pentatonic scale. As the name says uses five notes only. The major pentatonic scale uses the root, major 2nd, major 3rd, perfect 5th and major 6th. The minor pentatonic scale uses the root, minor 3rd, perfect 4th, perfect 5th and the minor 7th

The diatonic scales

Diatonic scales is what we use the most in western music. Each note in the scale is called a degree. The first degree of the scale in the root note, the second degree is called the supertonic. Each degree in the diatonic scale has a name. Each degree play a crucial role in establishing the tonality and harmonic structure of a piece. Here's an explanation of each term:

  1. Tonic (I): The tonic is the first scale degree of a diatonic scale and serves as the primary or "home" pitch. It provides a sense of resolution and stability. In Roman numeral analysis, it is represented by the numeral "I."
  2. Supertonic (II): The supertonic is the second scale degree. It has a tendency to create tension and often leads to the dominant or the mediant. In Roman numeral analysis, it is represented by the numeral "II."
  3. Mediant (III): The mediant is the third scale degree. It often provides a middle ground between the tonic and dominant, contributing to the overall harmonic color of a piece. In Roman numeral analysis, it is represented by the numeral "III."
  4. Subdominant (IV): The subdominant is the fourth scale degree. It lies between the tonic and dominant and is often associated with a feeling of preparation or departure from the tonic. In Roman numeral analysis, it is represented by the numeral "IV."
  5. Dominant (V): The dominant is the fifth scale degree and is known for its tension and desire to resolve back to the tonic. It adds a sense of energy and drive to the music. In Roman numeral analysis, it is represented by the numeral "V."
  6. Submediant (VI): The submediant is the sixth scale degree. It's located midway between the tonic and dominant and is often associated with a sense of calm or transition. In Roman numeral analysis, it is represented by the numeral "VI." These terms, along with the tonic, dominant, subdominant, and leading tone, contribute to the vocabulary used by musicians and music theorists to describe and analyze the harmonic structure of musical compositions. Understanding the roles and functions of these scale degrees enhances one's ability to interpret and create music.
  7. Leading Tone (VII): The leading tone is the seventh scale degree, located a half step below the tonic. It has a strong tendency to resolve upward to the tonic, creating a sense of tension and resolution. In Roman numeral analysis, it is represented by the numeral "VII." These terms are commonly used in the context of Western classical and popular music, especially when discussing harmonic progressions. Understanding the relationships and functions of these scale degrees is crucial for composers, arrangers, and musicians when creating and analyzing music. Roman numeral analysis, as mentioned, is a common method used to represent these scale degrees in written music theory.
  8. Subtonic (VII): The subtonic is the seventh scale degree, similar to the leading tone but a whole step below the tonic. Unlike the leading tone, the subtonic does not have as strong a tendency to resolve upward. In Roman numeral analysis, it is represented by the numeral "VII." We will find the subtonic in natural minor and descending melodic minor (see later chapter).

As we have seen the recipe for the major diatonic scale: whole whole half whole whole whole half. We can modify this recipe to build other scales such as the minor diatonic scale which is: whole half whole whole half whole whole. We just shift the recipe for the major diatonic scale by 2 to the right.

This "recipe" gives rise to two main scales that are used most of the time in western music:

  • Major: Bright and happy, with half steps positioned after the 3rd and 7th notes.
  • Minor: Introspective and often sad, with half steps after the 2nd and 7th notes.

Relative minor

As you've seen, we are just shifting the 5+2 progression for the minor scale. It means that depending on the note you start on, you will get the same notes as a major scale. Here is an example:

  • Major diatonic scale starting on C : CDEFGAB
  • Minor diatonic scale starting on A : ABCDEFG

As you've seen here, we use the same notes but the root note is different. Aminor is the relative minor to Cmajor.

Scales and key

Scales and keys, though often confused, serve distinct purposes in music:

  • Scale: A collection of notes arranged with specific intervals, offering a blueprint for melodies, chords, and harmonies. Think of it as a menu of ingredients for musical creation. Examples include major, minor, and pentatonic scales.
  • Key: A reference point defining the tonal center of a piece, establishing the "home base" and influencing which notes feel stable or tense. Imagine it as the foundation upon which a musical structure is built. Examples include C major, F minor, and A♭ major.

In short, scales provide the building blocks, while keys define the overall sonic landscape of a piece.

Melody vs Harmony

A melody is sequence of single pitches forming the main musical line, often played or sung by a lead instrument or voice, with recognizable motifs and emotional qualities.

Harmony is the simultaneous combination of different musical notes to create chords, providing a foundation and context for the melody. Harmony adds richness, texture, and emotional depth to the overall musical composition. It can be as simple as 2 notes on a piano and as complex as a whole orchestra playing together.

Melody is the horizontal, linear aspect, while harmony is the vertical, involving stacked notes. Together, they create a cohesive and expressive musical experience, with melody as the memorable tune and harmony supporting and enhancing the overall sound.


In music theory, a triad is a chord (harmony) consisting of three notes: the root, the third, and the fifth. These three notes are stacked on top of each other to create a harmonious sound. Triads are fundamental building blocks in Western music and are used in the construction of more complex chords and chord progressions.

We can build 4 different triads by stacking third intervals:

  • The major triad: Root + major 3rd + minor 3rd. For example CEG
  • The minor triad: Root + minor 3rd + major 3rd. For example CEbG
  • The diminished triad: Root + minor 3rd + minor 3rd. For example CEbGb. As you can see here, the diminished triad contains a tritone, 3 whole steps between the C and the Gb. As explained before, the tritone is very dissonant and this chord will be dissonant.
  • The augmented triad: Root + major 3rd + major 3rd. For example CEG#. This triad is not very common, it doesn't contain the perfect 5th.

Note: we use a bemol symbol here instead of a sharp to note that we lower the 3rd or 5th instead of augmenting a major 2nd or a fourth.

Triads in a key

Now let's build all the triads on top of the major diatonic scale. You will see that it uses both major, minor and dimished triads. Let's do that in the key of C.

  • C (root): C E G -> it makes up a major triad. root + major 3rd + minor 3rd.
  • D (major 2nd): D F A -> it's a minor triad.
  • E (major 3rd): E G B -> it's a minor triad.
  • F (perfect 4th): F A C -> it's a major triad.
  • G (perfect 5th): G B D -> it's a major triad.
  • A (major 6th): A C E -> it's a minor triad.
  • B (major 7th): B D F -> it's a diminished triad.

Let's quickly do the same for the triads on top of the minor diatonic scale in the key of C.

  • C (root): C E G -> it makes up a minor triad.
  • D (minor 2nd): D F Ab -> it's a major triad.
  • Eb (minor 3rd): E G Bb -> it's a diminished triad.
  • F (perfect 4th): F Ab C -> it's a minor triad.
  • G (perfect 5th): G B D -> it's a major triad.
  • Ab (minor 6th): A C E -> it's a minor triad.
  • Bb (minor 7th): B D F -> it's a diminished triad.


In music theory, modes are frameworks that color melodies and harmonies, adding character and depth to compositions.

Imagine the major scale you know (C major: C D E F G A B C). Each note in this scale can become the starting point for a different mode. Each mode has its own characteristic sound based on the arrangement of whole and half steps between its notes. There are seven main modes traditionally derived from the major scale, each with its own name: Ionian (major), Dorian, Phrygian, Lydian, Mixolydian, Aeolian (minor), and Locrian.

  • Ionian: The familiar major scale you already know. Sounds bright and happy. CDEFGAB
  • Dorian: Starts on the second note of the major scale. Offers a slightly minor feel with a touch of mystery. DEFGABC
  • Phrygian: Starts on the third note. Sounds more exotic and melancholic. EFGABCD
  • Lydian: Starts on the fourth note. Has a brighter, major sound with a unique twist. FGABCDE
  • Mixolydian: Starts on the fifth note. Creates a bluesy, jazz-like feel. GABCDEF
  • Aeolian: The familiar minor scale you know. Sounds sad and introspective. ABCDEFG
  • Locrian: Starts on the seventh note. Has a darker, more dissonant sound. BCDEFGA

Music throughout history has utilized modes, from ancient Greek music to medieval chants and beyond. Today, you'll find them in various genres: classical, jazz, rock, folk, and even pop music. Modes add variety and emotional depth to melodies and harmonies, giving musicians a broader palette to express themselves.

Natural, harmonic and melodic minor

What we call natural minor is the minor diatonic scale with the intervals: whole half whole whole half whole whole. If we translate that to notes in the key of Aminor we get ABCDEFG.

The 7th degree in a major diatonic scale is called the leading tone because it sits a half step below the root note (the tonic). This leading tone is very useful because it wants to resolve onto the root note. In a minor diatonic scale we don't have the leading tone because the 7th degree is a minor 7th, a whole step below the root note.

This lack of leading tone in the natural minor caused the creation of what we call harmonic minor. Derived from the natural minor, the harmonic minor takes a bold step by raising the seventh degree by a half step. This introduces the leading tone, creating a bittersweet tension that resolves strongly to the tonic. Imagine the dramatic flair it adds to classical pieces or the chromatic exploration it enables in jazz improvisation. The harmonic minor walks a tightrope between major and minor, offering a unique emotional depth.

In harmonic minor, we will often see the triad built upon the 5th degree of the scale to be a major chord instead of a minor chord because of the raised 7th degree.

Unlike the previous two, the melodic minor has a split personality. Ascending, it raises both the sixth and seventh degrees, creating a smoother climb to the tonic compared to the natural minor's awkward jump from the minor 6th to the major 6th (a whole step + a half step). This smoother ascent is favored in improvisational styles like jazz, where melodic lines flow freely. However, when descending, the melodic minor sheds its disguise and reverts back to the familiar natural minor form. This duality allows for contrasting melodic expressions within a single piece.

Understanding these minor scales is like having access to a wider range of colors on your musical palette. Each offers distinct characters: the natural minor's gentle sadness, the harmonic minor's bittersweet tension, and the melodic minor's chameleon-like adaptability.

Chord inversion

Chord inversion is a concept in music theory that involves changing the order or arrangement of the notes within a chord. A chord is typically made up of three or more notes played simultaneously, and these notes are often referred to as the root, third, and fifth. When these notes are rearranged, creating different configurations, it results in chord inversions.

There are three main types of chord inversions:

  • Root Position: The original or basic form of a chord where the root note is in the bass (lowest pitch), and the other notes are stacked above it.
  • First Inversion: The lowest note is the chord's third instead of the root. This means the root note has moved up an octave, and the third is now the lowest note.
  • Second Inversion: The lowest note is the chord's fifth instead of the root. Both the root and the third have moved up octaves, and the fifth is now in the bass.

Chord inversions are useful for creating smooth and interesting harmonic progressions, providing a sense of movement and avoiding large jumps between chords. Inversions also contribute to the overall sound and voicing of a musical piece, allowing for variety and richness in chord progressions. Musicians often use inversions to create a more seamless and flowing harmonic structure in their compositions or arrangements.

Tension and resolution

This topic is very broad. Building tension in music is often achieved through the use of dissonant intervals and harmonic progressions that create a sense of instability, which is then resolved by moving to more stable and consonant intervals or chords. The resolution of the fifth degree (dominant) with an added 7th to the root (tonic) is a classic example of tension and resolution in music theory. Here's how it works:

The dominant seventh chord, often denoted as V7, is a chord built on the fifth scale degree of a diatonic scale. In the key of C major, for example, the G7 chord is the dominant seventh chord. The dominant seventh chord introduces tension through the tritone, an interval of three whole tones or six half steps. In the G7 chord in the key of C major, the tritone is formed between the notes B and F. The tritone within the dominant seventh chord creates a strong desire for resolution. This tension is resolved by moving to a more stable and consonant chord, often the tonic (I) chord. In the key of C major, the resolution would be from G7 to C.

The V7-I cadence is a powerful harmonic progression that exploits this tension and resolution. The dominant seventh chord (V7) creates anticipation, and the resolution to the tonic chord (I) provides a satisfying conclusion, establishing a sense of tonal stability.

Functional Harmony: This tension and resolution between the dominant and tonic chords are fundamental to functional harmony, which forms the basis of much Western classical and popular music. The movement from the dominant to the tonic, especially when the dominant seventh chord is used, is a powerful tool for building and releasing tension in music. The dissonance introduced by the tritone in the dominant seventh chord creates an expectation for resolution, making the transition to the stable tonic chord a satisfying and conclusive moment in the musical narrative.

The 7th

Adding a seventh on top of a triad involves extending the basic three-note chord (triad) by including a fourth note, specifically the seventh scale degree. This extended chord, known as a seventh chord, is a common practice in music theory and is prevalent in various genres, especially jazz.

A triad consists of the root, third, and fifth scale degrees. For example, in the C major triad, the notes are C (root), E (third), and G (fifth). Adding a seventh involves including the seventh scale degree, creating a four-note chord. In the case of the C major seventh chord, it includes the notes C (root), E (third), G (fifth), and B (seventh).

Seventh chords introduce greater harmonic complexity and color compared to basic triads. The addition of the seventh creates a richer, more layered sound. The seventh chord contributes to the tension and resolution dynamic in music, as the seventh often seeks resolution to the next chord tone.

Seventh chords are used in various musical contexts, but they are particularly prevalent in jazz and related genres. In jazz, seventh chords are standard and widely used, providing a more sophisticated and harmonically dense palette. They add depth to chord progressions and allow for more interesting harmonic movements.

Jazz music often features extended harmonies and complex chord progressions, making seventh chords a natural fit for the genre's improvisational and expressive nature. Seventh chords offer greater possibilities for tension and release, which aligns with the improvisational style of jazz musicians. Extended Chords (9th, 11th, 13th):

Beyond the seventh, jazz and other genres commonly use extended chords with added ninths, elevenths, and thirteenths. For example, a Cmaj9 chord includes the notes C (root), E (third), G (fifth), B (seventh), and D (ninth). These extended chords provide even more color and complexity to harmonic progressions, contributing to the sophisticated sound characteristic of jazz and certain contemporary styles.

In summary, adding a seventh to a triad enhances harmonic richness and introduces tension and resolution. Seventh chords are standard in jazz due to their expressive potential and compatibility with the genre's improvisational nature. Extended chords with added 9th, 11th, and 13th further expand the harmonic palette, offering musicians additional tools for creative expression.

Key change (modulation)

A key change, also known as modulation, occurs when a piece of music shifts from one tonal center or key to another. This change introduces a new set of pitches as the tonal center, altering the overall harmonic and melodic framework of the composition. Key changes can add variety, emotion, and interest to a musical piece. Here are some key points about key changes:

Common Types of Key Changes:

  • Direct Modulation: The transition from one key to another is abrupt and direct.
  • Common-Chord Modulation: A chord is shared between the original and new keys, creating a smoother transition.
  • Sequential Modulation: The key change occurs through a sequence of chords that gradually move to the new tonal center.

Key changes can evoke different emotions and moods, providing contrast within a piece. Key changes often mark structural divisions in a composition, such as the transition between sections or the beginning of a new movement.

Methods of Achieving Key Changes:

  • Chromatic Movement: Moving chromatically between chords or notes can lead to a key change.
  • Circle of Fifths: Progressing through the circle of fifths or its relative minor/major can smoothly transition to a new key.
  • Pivot Chords: Using a chord that exists in both the current and new keys facilitates a seamless transition.

Common Modulation Techniques:

  • Up a Perfect Fifth: Modulating up a perfect fifth is a common and powerful modulation in classical and popular music.
  • Relative Major/Minor: Switching between a major key and its relative minor or vice versa provides a contrasting yet related tonal shift.
  • Parallel Key: Modulating between major and minor keys with the same root (parallel keys) is another effective technique.

Classical music composers often used key changes to navigate through different movements or sections, providing structural coherence. Key changes are frequent in jazz, contributing to the genre's harmonic complexity and improvisational nature. Many pop songs use key changes in the bridge or final chorus to heighten emotional impact or add excitement.

Key changes are a powerful tool for composers and arrangers, allowing them to shape the overall structure and emotional landscape of a musical piece. Whether subtle or dramatic, a well-executed key change can captivate the listener and bring a fresh perspective to the musical narrative.

Blues music

Blues music is characterized by its distinctive sound, which often involves specific techniques and deviations from traditional Western music theory.

While blues music can incorporate both major and minor tonalities, it is common for blues to have a predominantly minor tonality. The use of minor keys contributes to the characteristic "bluesy" sound, evoking a sense of melancholy and emotional depth. However, it's important to note that blues often involves a blending of major and minor elements, creating a hybrid tonality.

The 12-bar blues, one of the most iconic and widely used blues progressions, is frequently built around a minor tonality. In a basic 12-bar blues in the key of A, for example, the chords might include A7, D7, and E7, where the dominant seventh chords contribute to the blues sound. Even though the A7 chord is dominant, it still carries a minor seventh, emphasizing the minor tonality.

That said, blues musicians often introduce variations and nuances in tonality, and major elements are not uncommon. Some blues compositions and progressions may feature major chords, particularly dominant seventh chords with a major third, adding complexity and versatility to the genre. This mixture of major and minor elements is one of the factors that make blues music rich, expressive, and diverse.

Here's an explanation of few blues techniques related to music theory:

  1. The Tritone: The tritone is an interval spanning three whole tones or six half steps. In blues, the tritone plays a crucial role, often found in the blues scale and dominant seventh chords. The tritone is a defining characteristic of the blues sound, contributing to its tension and bluesy flavor. It can be found in the blues scale, often between the third and fourth or seventh and root degrees. Dominant seventh chords, common in blues progressions, contain a tritone between the third and seventh degrees. Tritones create a sense of tension, and their resolution is a key element in blues progressions. For example, in a dominant seventh chord (e.g., G7), the tritone (B and F) resolves to a more stable interval (C and E in the key of G).
  2. Using major chords instead of minor chords: Blues frequently employs dominant seventh chords, which are neither strictly major nor minor but contain major thirds. This ambiguity contributes to the bluesy sound. Major chords, particularly dominant seventh chords, are used even in situations where traditional Western theory might suggest a minor chord. For instance, a blues progression in the key of G might use G7 instead of Gm. Dominant seventh chords, with their major third and minor seventh, add tension and are a fundamental harmonic element in blues. The major third creates a major-minor hybrid quality that defines the blues sound.
  3. Using major scale melody over a minor key: Musicians playing over a blues progression may use the major pentatonic or major blues scale even if the underlying harmony is based on a minor key. This juxtaposition creates tension and a distinct blues flavor. For example, in the key of A minor blues, a guitarist might use the A major pentatonic or A major blues scale, blending major and minor elements.

In summary, blues techniques often involve the intentional use of the tritone, the incorporation of major chords, and the utilization of major scales over minor keys. These techniques contribute to the unique and expressive nature of blues music, creating tension, ambiguity, and the characteristic sound associated with the genre.

Rythm and music notation

In the American system, the whole note is referred to as a "whole note," and the quarter note is called a "quarter note." The duration of a whole note is generally considered to be four beats in a 4/4 time signature. In contrast, the quarter note represents one beat in the same context.

In the European system, the whole note is often called a "semibreve," and the quarter note is referred to as a "crotchet." Despite the different names, their durations remain consistent with the American system.

Rhythm is a fundamental aspect of music that governs the organization of sounds in time. It encompasses the arrangement of beats, durations of notes, and the overall pattern of accents. Here are several key concepts related to rhythm:

  • Beat: The beat is the basic unit of time in music. It serves as the pulse that provides a sense of regularity and helps organize musical events.

  • Meter: Meter defines the recurring pattern of strong and weak beats in a musical passage. Common meters include duple (two beats per measure) and triple (three beats per measure).

  • Time Signatures:

    • 4/4 Time Signature: In common time (4/4), there are four beats in each measure, and the quarter note typically receives one beat. The top number (4) indicates the number of beats per measure, and the bottom number (4) denotes that the quarter note gets one beat.
    • 3/4 Time Signature: In 3/4 time, there are three beats in each measure, and the quarter note usually receives one beat.
    • 4/8 Time Signature: In 4/8 time, there are four beats in each measure, and the eighth note typically receives one beat.
  • Tempo Markings:

    • Allegro: Fast and lively.
    • Andante: At a moderate pace.
    • Adagio: Slow and stately.
    • Presto: Very fast.
  • Tempo or Beats Per Minute (BPM): Tempo markings may also include a specific BPM value, indicating the number of beats per minute. For example, Allegro might be marked as "Allegro, quarter note = 120," meaning 120 beats per minute with the quarter note receiving one beat.

  • Note Duration: Different note values represent varying durations. Common note durations include whole notes, half notes, quarter notes, eighth notes, and sixteenth notes. The length of a note determines how long it is held or played.

  • Rests: Rests denote periods of silence in music. Like notes, rests come in various durations and contribute to the overall rhythmic structure.

  • Syncopation: Syncopation involves placing accents or emphasizing weak beats within a musical phrase. It adds a sense of unpredictability and energy to the rhythm, often creating a lively, offbeat feel.

  • Polyrhythm: Polyrhythm occurs when two or more conflicting rhythms are played simultaneously. This can create complex and layered rhythmic patterns, adding depth and interest to the music.

  • Swing Feel: Commonly associated with jazz and certain styles of popular music, the swing feel involves playing eighth notes with a rhythmic emphasis on the offbeat. This creates a relaxed, "swinging" groove.

  • Rhythmic Patterns: Many musical genres have characteristic rhythmic patterns. For instance, Latin music often features distinctive rhythms such as the clave pattern, while funk music is known for its intricate and syncopated grooves.

  • Rhythmic Variation: Musicians often use rhythmic variation to maintain interest and creativity in a piece. This can involve changing the rhythmic pattern, adding embellishments, or introducing unexpected accents.

  • Rhythm in Different Cultures: Various cultures around the world have unique rhythmic traditions. The rhythms of African, Indian, and Middle Eastern music, for example, offer rich and diverse approaches to rhythm.

Understanding and manipulating these rhythmic elements allows musicians to create engaging, dynamic, and expressive compositions across a wide range of musical genres. Rhythm is a powerful tool for conveying emotion, establishing groove, and shaping the overall character of a musical work.