Music Theory: Chords and Key Signatures Study Guide

Appointment and Key Signatures

This section introduces key concepts related to identifying and naming chords:

Students will be tested on naming or writing out chords based on provided information.
Key reference from the C major chord (C, E, G) is established.

The progression of chord naming follows the structure:
- Root: C
- Major Third: E
- Perfect Fifth: G
- Minor Seventh: B♭
- Extensions: 9, 11, 13
A useful counting method is shared: 1, 3, 5, 7, 9, 11, 13.
- The example here indicates that these chords are likely to be extensions or alterations of a minor chord, specifically identifying it as a minor chord based on the intervals counted.

It is stated that the key signature of C major contains no sharps or flats.
If discussing a C dominant seventh chord (C7), the alteration would occur at the seventh, implying it would be B♭ instead of B natural…
- For example, a C9 chord would include the altered note B♭: C, E, G, B♭, D.
- If a student is tasked to write it, understanding these placements is critical.

Students are encouraged to determine the key signature by identifying the chords at the bottom.
Chords can be written as major chords. The number of sharps in C major is five, corroborating earlier statements.

When alterations are added to chords beyond the seventh (e.g., C13), all altered notes must be accounted for:
- Example for C13: C7♭9♯11♭13.
- The focus is placed on retaining the chord's identity up to the seventh note before the alterations begin:
- The last non-altered note serves as the main reference point.

Notes such as B and E are named based on alterations which may appear after the seventh.
For example, a B major seventh chord can be expressed as:
- B7: B, D♯, F♯, A
- If adding alterations: B7♭9♯11♭13.
It is important to indicate that when extensions are free of additional alterations, they can be simply labeled without concern.
Structure shows that naming an altered chord follows this example:
- B13 without any other modifications can simply be expressed as such.

Students may engage in a naming exercise where they will spin a wheel to practice identifying chord types.
The practical aspect of interpretation is emphasized during verbal communication of the chords.

A repetition of the importance of understanding key signatures to identify alterations is examined. For instance, if a key signature is expected to show an F♯ in the guidelines but does not, the player acknowledges a deliberate change.
The key signature, depending on its major or relative minor, dictates how chords change:
- G major has A♯ where G minor lacks it.

The process for transitioning from a major to a minor is discussed with specific details about notes involved for conversion:
- Example Conversion: G major (G, B, D, F♯) to G minor (G, B♭, D, F).
The characteristics of intervals between notes are defined, indicating the significance of dissonance in chord conversions, specifically concerning semitone relationships in C major and other chords.

The intervals such as between B and C are noted as being a semitone, with additional discussions about how raising certain notes (such as the 11th in dominant chords) can help avoid dissonant sounds.
The importance of understanding how alterations impact chord structure and sound is highlighted, especially in genres like jazz.

Dominant chords and major chords require the 11 to be raised, while minor and diminished do not.
Establishing that a clear distinction exists in naming and structuring dominant chords with alterations such as:
- Dominant seventh chords retain their altered notes (B7♭9 etc.) as they provide clarity in reader understanding.
Clarifications made on whether chords can be classified based on structural variation to identify if they retain their characteristics despite alterations.