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Physics of Music Lecture 11

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Musician blows into wind way, tone is generated by turbulence at ... Unstopped, stopped. Harmonic Flute with overtone hole. 5 November 2002. Phys 332W Woodwinds ... – PowerPoint PPT presentation

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Title: Physics of Music Lecture 11


1
Physics of MusicLecture 11
  • Woodwind Instruments
  • Berg Stork Chapter 10.
  • Prof. Charles Hyde-Wright
  • Old Dominion University

2
Wind Instruments
  • Woodwinds
  • Resonant Tube
  • Sound made by
  • Edge tone
  • Recorder, Flute, Organ
  • Single Reed
  • Clarinet, Saxophone, Organ
  • Double Reed
  • Oboe, English Horn, Bassoon,
  • Shawm, Krummhorn
  • Brass
  • Resonant Tube
  • Sound made by lips
  • Trumpet, Trombone, French horn,

3
Early Woodwinds
  • 9000 year old clay flute from China
  • Pre-historic clay, bone flutes
  • Bamboo flutes

4
Medieval RenaissanceWoodwinds
  • Capped Reed Krummhorn, etc
  • Double reed enclosed in a box, musician blows
    into wind way.
  • Fipple flutes Tabor flute, Recorder, whistle.
  • Musician blows into wind way, tone is generated
    by turbulence at an edge
  • Early instruments had cylindrical bores.
  • Conical bores developed to modify tone and give
    more flexibility in laying out fingering holes
  • Simple holes (8 on recorder) almost no keys
  • Every instrument came in a family of different
    sizes
  • Soprano, Tenor, Alto, Baritone, Bass All
    dimensions scaled

5
Tabor FlutePlayed by minstrels while
simultaneously beating a drum and dancing.
  • Very narrow cylindrical bore.
  • Fundamental does not sound
  • Harmonic series is 2/21, 3/2, 2, 5/2, 3
  • E.g. C5 G5 C6 E6 G6
  • Over blow to select any note from harmonic
    series.
  • With end covered by hand, harmonics
  • ¾, 5/4, 7/4,
  • G4, E5, B-flat/A5,
  • Two finger holes near end can fill in missing
    notes
  • Tube Open C, D, D
  • (Like a trumpet)

6
Recorder Resonance
  • Turbulence of edge tone creates noise (all
    frequencies stimulated
  • Negative amplitude reflection of pressure wave
    from end of tube interferes with edge tone
    turbulence.
  • (twice length of recorder)/(speed of sound) time
    for pressure wave to reflect off end and come
    back to source.
  • This reflected wave will reinforce those
    frequencies in the edge tone with
  • Frequency n S/(2L), n1,2, 3 harmonic series

7
Recorder Fingering
  • Pressure wave is zero at each end
  • 7 finger holes 1 thumb hole
  • Opening the last hole effectively shortens the
    instrument (try E5 E6 B7) //0 //0
    /0/0.
  • If the hole is smaller than the bore (or only
    partially opened) the effective length of the
    instrument is a little longer than the distance
    to the finger hole
  • Last two finder holes are double, small holes.
  • Blowing harder favors the 2nd or 3rd harmonic
    over the fundamental (shifts the pink noise).
  • This is further enhanced by opening the thumb
    hole, which favors the creation of a node halfway

8
Fingering
9
BaroqueRecorder Conical Bore voicing
fingering
  • Recorder has (inversed tapered) conical bore,
    narrowing at far end.
  • Moves effective position of pressure node beyond
    length L of recorder.
  • Antinode of 2nd harmonic moves towards end.

10
RecorderForked Fingering
  • A full chromatic scale requires many forked
    fingerings
  • Opening the next to last finger has less effect
    than opening the last two fingers.
  • Every half step must shift the effective length
    of the instrument by 5.75(even though we have
    fat fingers).
  • We want to find 12 half steps with only eight
    fingers

11
Double Reeds
  • Older than single reeds (except organ)
  • Krummhorn Capped reed
  • Shawm Lips directly on reed, no keys
  • Oboe, Bassoon, English Horn
  • Fingerings enhanced by keys to add more
    combinations of hole positions and sizes.
  • Keys extend hand reach for Bassoon.

12
Reeds Source of Vibration
  • Flow of air through reed opening drops the
    pressure (Bernoulli effect)
  • Reeds are forced together by over pressure on
    outside
  • With the air flow cut-off, the Bernoulli effect
    stops, the reeds rebound by their elasticity.
  • Stiffness and mass of reed, set a broad resonance
    (range of frequencies) for the reed vibrations.
  • Reflections of sound waves in tube reinforces
    the vibrations at the frequencies of the tube
    resonances (fundamental and harmonics).
  • Reed acts as closed end. But reed in Conical
    tube acts like open end of cylindrical tube
  • Oboe, Bassoon,
  • Integer harmonics 1,2,3
  • 2nd harmonic is one octave above
    fundamental(first harmonic).

13
Single ReedsChalumeau, Clarinet, Saxophone
  • Single Reed in cylindrical bore
  • 2nd Harmonic at 3 x fundamental frequency
  • Need 19 fingerings for Octave Fifth Difficult!
  • Chalumeau is early precursor.
  • Double holes for pitch control (like recorder)
  • Register key (now optimal placement is 1/3)
  • One or two keys for fingers.
  • Chalumeau is played upside down (reed on top).
  • Acoustics require much less air pressure
  • Diameter of bore? Shape of mouthpiece??

14
Clarinet
  • Most recent of modern symphonic instruments.
  • Mozart is earliest composerbut not for modern
    clarinet (also J.Christian Bach)
  • Low register of clarinet is Chalumeau
  • Middle register is clarinet register
  • High register dominated by complicated fingerings

15
Transposing Instrument
  • Clarinet C is actually B-flat on piano
  • Simplest scale on clarinet is defined to be
    C-major scale.
  • Size of hands dictates that Clarinet C-Major
    scale is shifted down 1 whole step on piano to
    B-flat major

16
Fingering of Clarinet Flute
  • Böhm system circa 1850
  • Rings and keys
  • Each finger activates several pads.
  • Combinations of fingers are not the same as the
    sum of the individual fingers.
  • Clarinet acoustics is also affected by the
    chamfering given to individual finger and pad
    holes.

17
Modern Flute
  • Thin Walled cylindrical Tube
  • Bohm fingering mechanism
  • Head piece length adjusted.

18
Organ Pipe Styles Flute
  • Straight flue type pipes .wav file
  • straight "flue-string" thin diameter cylinder
  • Flute with tuning extension to flatten sound
  • Wider scale, stronger dominance of fundamental
  • Partial (open ended cap) 50 extension
  • Stopped with hand (Wide Pipe) sounds down A to
    B (almost 1 octave)
  • Wooden square Flute
  • Unstopped, stopped
  • Harmonic Flute with overtone hole

19
Organ Pipe Thin Flute
20
Organ Pipes Reeds .wav file
  • Trumpet Conical

21
Organ Pipes Clarinet, Cylindrical, closed
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