Dominant Extensions, Scales, and Wind Instrumentation

General Principles: Dominant extensions can be altered up or down by a semi-tone. Unaltered extensions are prominent in major keys, while altered extensions are more common in minor keys.
Functions: Chords function either in a traditional dominant-tonic relationship or as a tonic/temporary tonic.
9th Extensions:
- 9: Unaltered $M9$ above the root; effective as a tonic sound in funk or jazz.
- $b9$ : Not a stable tonic option; used to resolve to minor chords.
- $\#9$ : Often expressed as a $b10$ ( $b3rd$ ) voiced a $M7$ above the $M3$ .
11th Extensions: Nearly always raised to $\#11$ ; 5th is often omitted. Less frequent than 9ths and 13ths.
13th Extensions:
- The 11th is usually omitted.
- $b13$ : Only used as a transition chord; the 5th must be omitted. Usually used with an altered 9.
Altered Chords ( $Alt$ ): A blanket term for chords containing an altered 9 and 13. The most common commercial voicing is $\#9/b13$ .

Minor Scale Variations:
- Natural Minor: Based on the $6^{th}$ scale degree of major.
- Harmonic Minor: Natural minor with a raised $7^{th}$ .
- Melodic Minor: Harmonic minor with a raised $6^{th}$ .
Diatonic Modes:
- Dorian: Natural minor with a raised $6^{th}$ ; built off the $2^{nd}$ degree of major.
- Mixolydian: Major scale with a lowered $7^{th}$ ; built off the $5^{th}$ degree of major.
- Lydian: Major scale with a raised $4^{th}$ ; built off the $4^{th}$ degree of major.
Pentatonics: Effective for diatonic harmony when the melody does not need to specifically outline chord changes. Includes Major, minor, and Blues variations.

9th Chords: Can use a pentatonic scale starting a 5th above the root.
Major Chords with $\#11$ : Use a major pentatonic scale a $M2$ (two 5ths) above the root.
Minor Chords with 13: Use a minor pentatonic scale a $M2$ (two 5ths) above the root.

Flute: Transverse metal instrument without a reed. Registers: Low (breathy/weak), Middle (bright/singing), High (piercing/shrill).
Oboe: Double reed instrument made of wood. Registers: Low (thick/heavy), Middle (warm/reedy), High (thin/pinched).
Clarinet: Single reed instrument. Key registers: Chalumeau (deep/rich), Throat tones (pale), Clarino (bright/expressive), and High (piercing).
Bassoon: Double reed made of maple. Often doubles cellos and provides the low end of the woodwind section.
Saxophones: Available in Soprano, Alto, Tenor, and Baritone.

French Horn (Horn in F): Characterized by dark and focused lows and bright, heroic highs. Playability is generally limited above written $G_5$ .
Trumpet: Highly versatile with a large dynamic range; capable of fast chromatic passages but difficult to play quietly.
Trombone: Uses a slide, making slurring difficult. The bass trombone provides powerful, deep, and solid low registers.
Tuba: Provides the heavy foundation for thick chords but lacks agility and is limited by the player's breath.