Musical Acoustics

Scientists (physicians, engineers, technicians...) and artists (musicians, painters...) do not speak the same language. Musical instrument designers and makers need to understand both.

The science concerned with researching and describing the physics of sound is the acoustics. Acoustics deals with many disciplines not directly related with music as the ultrasonics, underwater, noise control, etc. but there are some branches that have big influence in music perception (psychoacoustics, electroacoustics, architectural, etc.) and other that specifically study the music and the musical instruments. Obviously, all of them share the same foundations (physical acoustics).

Music is most directly linked to feelings than thoughts, but there is some rationalism in music that is comprehended in what is called 'music theory'. While music theory is quite less accurate describing sounds than acoustics, all musicians prefer using it because music, as an art made of sounds to be perceived, is best described with it.

• The branch that studies the music and particularly the musical instruments is the Musical Acoustics.

They are the Musical Acoustics and a part of it termed Acoustics of Musical Instruments.

• Combination tones & Harmony
• Musical scales & temperament
• String Instruments
• Brass Instruments
• Woodwind Instruments
• Percussion Instruments
• Keyboard Instruments
• Speech production
• Singing

• General

  • Pitch Frequencies of Musical Notes
  • The sound of old instruments
  • Scales (general comments)
  • Just vs Equal Temperament
  • Western Scales and Chords
  • Pythagorean Scale
  • Pentatonic Scales
  • Hexatonic Scales
    • Blues Scales
  • Equal Tempered Scale - Table of Frequencies and Wavelengths in air
  • Equal Temperament compared to Mean Tone - Table of Frequencies
  • Some Other Scales
  • Making sense of cents

• Strings

  • Condiciones de contorno para una cuerda
  • Vibraciones de una cuerda fija por ambos extremos
  • Ondas estacionarias en una cuerda

  • Breaking Strength of Strings

  • String Tension and its relation with the pitch of the note produced when the string vibrates.

  • Strings Describe a Conical Section

  • Scale Length vs. Vibrating length
  • Calculating Fret Positions

  • Fret Placement

  • Compensation

• Air Columns. Tubes and Ducts

  • Conical vs Cylindrical Bores
    • Clarinet Comments
    • Saxophone Sounds
  • Terminating Impedance
  • Measuring propagation
  • Duct and Filter References

• Varillas

• Placas

• Membranes

• Resonance Boxes

In conventional musical parlance, the vertical chordal structure of music, in contrast to the horizontal melodic structure. The terms 'vertical' and 'horizontal' derive from western music notation where these graphic dimensions are used to prescribe events in PITCH and time, respectively. This division is analytic, as all sound happens in both dimensions (and others) at once. See: POLYPHONY.

In modern musical parlance, harmony is chordal process in music, i.e. pitch relations: among pitches in groups called chords, and among the chords. The manner in which the pitches are articulated is open, from simultaneously or 'vertically' to sequentially or 'horizontally'. In western pedagogy, harmony usually refers to a closed, systematic study of these relations in the music of 18th and 19th century Europe.

Colloquially, the term is used primarily as equivalent to concord and CONSONANCE, that is, expressing the pleasing combination of two or more sounds.

Compare: DISSONANCE.

Music combining two or more different melodic parts, in contrast to monophony or single melody, and to homophony which combines several parts of similar or identical RHYTHM.

Compare: HARMONY.

Musical Acoustics

Musical instruments are enjoyed throughout the world, not only for their musical quality, but also their unique sound or tone quality. This module on musical acoustics describes each family of musical instruments and discusses the acoustic properties that make that family unique.

There are six chapters in this module making it longer than the other modules. In the first chapter you will learn about musical scales and how the equal tempered scale was derived. The other five chapters will cover in detail the acoustics of each musical instrument family.

String

The string family consist of instruments like the violin, viola, Cello, Bass, and Guitar. They create sound by plucking, striking, or by running a bow across the string. The strings themselves make very little sound. The body of the instrument is used to amplify the sound.

In this chapter, you will learn about the vibration patterns of stringed instruments, how they are related to each other, and how their sound is generated, modified, and amplified.

The violin and other bowed string instruments (Viola Cello Bass New family of fiddle)
History
Construction
Plucked string Vibration
Bowed string Vibration
Violin body Vibration
Tuning the top and back plate
The bridge

The guitar
Construction
The guitar as a vibrating system
top plate Vibration
back plate Vibration
air cavity Vibration
Resonance of the guitar body
Sound radiation
Electric guitar
Strings, frets, & compensation

Brass

Brass instruments are the heart of the concert or marching band, but you will also find them in an orchestra. Members of the brass family include the trumpet, tuba, French horn, and trombone. Brass instruments have a mouth piece, and when played, the player's lips act as a valve. This introduces puffs of air that maintain oscillations of the air column.

Instruments in the Brass family
Tuba
Trombone
Trumpet
French horn

Brass acoustics
Oscillations in a pipe
Impedance curves

Woodwinds

Woodwinds consist of instruments like the clarinet, flute, saxophone, oboe and bassoon. Originally they were made out of wood. Today they may be made out of wood, or other materials such as plastic or metal. Woodwind instruments produce sound using a mechanical or air reed with the frequency determined by air traveling down the pipe.

Instruments in the Woodwind family.
Clarinet
Saxophone
Oboe
Bassoon
Flute
Recorder

Vibration of a pipe-reed system.
Regenerative feedback
Impedance curves
Tone holes
Bore types
Registers & register holes

Mechanical reed instruments
Clarinet
Double reed (oboe, bassoon)
Saxophone

Oscillating air streams and whistles.
Flute
Recorder
Organ Pipes

Percussion

Grab a couple of sticks, bang them together and you have a percussion instrument. Oftentimes when you think of percussion instruments, a drum is the first thing that comes to mind. However the percussion family includes a vast array of instruments. The percussion family includes; drums, the piano, chimes, marimba, cymbals, whistles, the harpsichord and many others. The percussion family produces sound as vibrating bars, vibrating membranes, or vibrating plates.

In this chapter we will focus on two groups of percussion instruments; the membranophones (drums) and the idiophones (xylophone, marimba, chimes,cymbals, etc.)

Instrument Classification
Idiophone
Membranophone
Aerophone
Chordophone

Vibration of bars
Glockenspeil
Marimba
Xylophone
Vibes
Chimes
Triangles

Vibrations of membranes
Timpani
Bass drum
Snare drum
Other drums

Vibration of plates
Cymbals
Gong and tam tams
Steel drums
Bells and carillons
Hand bells

Keyboard

The piano (invented in 1709 by Bartolomeo Cristofori in Florence) is often considered to be the most popular instrument of all. Although the piano is a stringed instrument and at times is considered part of the percussion family (the strings are hammered), it is often grouped with other keyboard instruments to form an additional musical family.

In this chapter you will learn about the Piano, Clavichord, Harpsichord, Harp, and Pipe Organ.