Classification of Musical Instruments and Alterations

Instrument Timbre and Classification

Instrumental timbres occur based on what the voices perceive:

• Appearance: If you hear a deep sound, you immediately associate it with a large instrument; if you hear an acute sound, you will think of an instrument of small dimensions.
• Material: Instruments can be found made of wood or built of metal.
• Playing Method: The way the instrument is played, such as blowing, plucking, or striking (percussion).

1. The String Family

1.1 Bowed Strings

Violin, viola, cello, and double bass.

1.2 Plucked Strings

• Those in which sound is produced by plucking the strings with a plectrum, such as the guitar.
• Those using a keyboard, such as the harpsichord.

1.3 Struck Strings

The piano.

2. The Wind Family

2.1 Woodwind Instruments

Instruments where wood is involved in most of its construction, such as the clarinet, flute, oboe, saxophone, and bassoon. They present softer, sweet, and pleasant sounds.

2.2 Brass Instruments

Instruments composed of metal in the total or most of their design, providing a powerful and bright sound. Examples include the trumpet, trombone, horn, and tuba.

2.3 Other Wind Instruments

Devices located inside a tool for their specific use that may not fit into the above groups, such as the accordion, harmonica, and organ.

3. The Percussion Family

3.1 Definite Pitch (Tuned)

Instruments that produce sounds where the height determines specific notes that can be written on the staff, such as the timpani and xylophone.

3.2 Indefinite Pitch (Untuned)

All those instruments that, when struck, scraped, or rubbed, produce sounds of indeterminate height where specific notes cannot be written on the staff, such as the triangle, bells, drum, bass drum, and rattle.

Musical Alterations and Accidentals

Alterations are musical signs used to modify the pitch of the notes:

• The Sharp (#): Increases the pitch of the note by one semitone.
• The Double Sharp (x): Raises the pitch of the note by one whole tone.
• The Flat (b): Lowers the pitch of the note by one semitone.
• The Natural (♮): Reverses the effects of sharps and flats, restoring the note to its natural height.

Basic Rules for Alterations

• The alteration is placed on the staff, holding the note to its left.
• When an altered note is tied, the subsequent note is also affected.
• The effect of an alteration also rests on all notes of the same name within the measure.

Accidental alterations only temporarily modify certain notes of a musical work.

Key signature alterations modify notes throughout the entire musical work unless they are canceled with a natural sign or modified with another alteration. The set of these alterations is the key signature, written between the clef and the time signature.