Transcript Cottingham-1 - CCRMA

CCRMA – Stanford University
Music 318 – Free Reed Instruments
13 February 2013
Eastern and Western free reed
mouth organs: Acoustics and
history
James P. Cottingham
Physics Department
Coe College
Cedar Rapids, Iowa
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Property of
Thomas Rossing
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The free reed instruments --•
I. The Asian free reed mouth organs (today)
– khaen, naw
– sheng, sho
– bawu, hulusi
•
II. Western free reed instruments (2nd session)
– harmonica
– reed organ and harmonium
– accordion/concertina family
•
III. Pitch Bending (2nd session)
– harmonica
– ree reeds with pipes
– accordion
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I. The Asian free reed mouth organs --A. Overview of Eastern and Western free reed
instruments with some examples
B. Some ancient Asian instruments
C. The khaen: construction and acoustics
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A. Asian Mouth Organs
Pipes
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Western Mouth Organs
No Pipes
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ACKNOWLEDGMENTS
•
Pat Missin (www.patmissin.com) for use of photos and sound
clips. The sound examples are played by Pat Missin.
•
Terry E. Miller, Profesor Emeritus, Kent State University, for
providing expert advice and opinion on the Asian free reed mouth
organs, as well as video of khaen making
•
Lydia Ayers, Composer and former Visiting Professor, Hong Kong
University of Science & Technology for 3 animated slides of
Chinese free reed mouth organs
• Financial support from:
• The National Science Foundation REU Grant No. PHY1004860
• The Coe College Acoustics Research fund
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The free reed instruments --two main families
The Asian free reed mouth organs use flat, symmetric free
reeds like the reed from a sheng (left)
The Western free reed instruments, first developed around
1800, use “offset” reeds like the one from an American reed
organ (right)
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P1
P2
• Cross-sectional view of a free reed used in Western free reed
instruments.
• The solid line represents the position of the reed at rest.
• The dashed lines show approximate maximum excursions for
the blown vibrating reed.
• This reed will normally only sound for a pressure difference P1
> P2.
• The thickness of the reed plate (grey) varies from instrument to
instrument.
• In some cases the reed tip may never pass below the reed
plate.
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Free reeds in Asian mouth organs
•The elastic tongue vibrates through the frame
•The reeds are symmetric: the vibrating tongue is cut from the
frame
•Reeds can be chiseled form a strip of metal…
• or cut from cane or bamboo…
•The same note can sound on both pressure (exhaling) and
vacuum (inhaling)
•These symmetric free reeds must be coupled to a resonator
Asian free reed instruments - History
• The Asian free reed instruments are undoubtedly of
ancient origin
• Most evolved as folk instruments with little or no historical
documentation
• Major exceptions to this are the instruments used in the
courts of China and Japan
• The sheng is mentioned in Chinese sources of the 11-12th
century BC
• The Shih-Ching reports the sheng used by ordinary
people before the time of Confucius
• Confucius (551-479 BC) is believed to have played the
sheng.
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The Asian mouth organs:
Free reed coupled to pipe
Symmetric reeds
Often operate on both directions of airflow
Reeds normally function as a “blown open” reed
The sounding frequency is above both the
natural frequency of the reed and the resonance
frequency of the pipe
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Typical Asian free reed mouth organs
1. Single free reed pipe with finger holes:
2. Multiple pipe instruments:
gourd pipe
khaen
hulusheng
naw
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Complete khaen demonstrated (lai soi)
Free-reed pipes with finger holes
• Reed is placed at the closed end of a bamboo tube
TM
Closed end –
plugged
reed
bawu
• Tone quality varies with number of finger holes covered
• A variation: gourd pipe with finger holes
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• The bawu has a metal free reed which
produces a sound similar to the clarinet.
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Free-reed pipes with finger holes
• Reed is placed at the closed end of a bamboo tube
• Tone quality varies with number of finger holes covered
bawu - all tone holes closed
bawu - 4 of 8 tone
holes closed
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Frequency of a bawu as a function of pipe resonance
frequency. Solid elliptical data points from underblowing are
near the reed frequency (horizontal line).
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Sound example on the free reed pipe ala
(Vietnam)
Pat Missin
• One pipe
similar to a
bawu and
one drone
pipe with
the reeds in
a gourd
wind
chamber
• A free reed mouth
organ usually played
by closing several
pipes at a time
• The reeds are in the
closed ends of the
pipes in a wind
chamber.
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B. Some ancient free reed instruments
from Southeast Asia
• Some of the very simplest free reed wind
instruments:
A typical multipipe free reed mouth organ
(hulusheng, naw, …)
naw (hulusheng)
naw pipe 1.5
f1 = 433 Hz
Open
Naw Pipe 1.5
Impedance
f1 = 354 Hz
mouth-resonated
lamellophones
(“jew’s harps”)
•
common throughout Southeast Asia
•
sides of the vibrating tongue cut from a single piece of wood, bamboo, or
metal
•
Tongue is not be plucked directly, but is excited by plucking the frame
•
played by placing the reed tongue over the lips of the player and using the
vocal tract as a resonator.
•
Some traditional uses:
– signaling
– disguising the voice
– imitation of natural sounds (such as frog calls)
dan moi (Vietnam)
huntoong
plucked
blown
enggung
(Bali)
•constructed from a single piece of bamboo
•designed as a wind instrument:
•a single reed to be blown
•the player can vary the pitch by changing the shape
of the vocal tract (pitch bending)
enggung
… can be used (among other things) to imitate frog calls
enggung
The free-reed horn
•
Water buffalo or ox horn hollowed
out and fitted with free reed:
•
Wax used to seal the reed (and
possibly for tuning)
•
Player can blow or suck to produce
one of three notes:
1. Both ends open
2. Narrow end closed with hand
3. Both ends closed
www.cambodianlivingarts.org
The free-reed horn
The free-reed horn
C: Construction and operation of the Southeast
Asian free reed mouth organ: khaen
C. Outline
• The khaen:
– Design and Construction
– Acoustical properties
– The khaen – an ethnographic instrument
• Video clips of khaen making - Terry Miller
(1988)
The khaen
• 16 (or 6, 14, 18) free-reed bamboo pipes
• Reeds of copper-silver alloy located at L/4 for
each pipe
• All reeds contained in a carved hardwood
windchest
• Reed section sealed in windchest by a black
insect product, kishut
• Tuning slots set effective pipe length to
determine pitch
• Finger holes burned in each pipe control tone
production
• Player activates reed by blowing or inhaling
while covering appropriate finger holes
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The khaen is the signature instrument
of the Lao people of
Northeastern Thailand and Laos
Tuning slots
Reed
The khaen reed
19th century Thai coinage metal has been
“traditionally” used to make the reeds.
[Above: Thailand 2 att (1882)]
reed
Khaen reed mounted pipe
Sounding frequency as a function of reed
length (composite for 3 khaen)
Reeds are typically made in two sizes. Pipe length
is used to tune each reed-pipe to desired pitch.
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Khaen Pipe Impedance Curve
Khaen Pipe 4-10
Calculated Impedance
Tuning
slots
reed
Reed is located
near L/4
Variation of sounding frequency with
pipe length for a khaen pipe
The reed-pipe sounds slightly above the pipe resonance frequency
The khaen as ethnographic instrument
• Detail of martial dancers and mouth organ players
from a Vietnamese bronze gong [from the Garland
Encyclopedia of Music]
The khaen as a symbol of the Lao people of
Northeast Thailand
• Unlike many Asian traditional instruments, the khaen has not
undergone any modernization
• Despite dramatic changes in rural Thai society in the last 50
years, khaen making has not changed
• The good ones are still made by village craftsmen
• The khaen’s symbolic meaning has also changed little
• A khaen (unamplified) now often appears with an ensemble
including electric guitars and drums, identifying the music as
“Northeastern.”
Making a khaen reed
Strip of metal is
thinned by pounding
reed
tongue
Three free sides of reed tongue
are created using a small chisel.
It is traditional to use the elephant
bone.
SEM image of portion of khaen reed. The scratches parallel to
the reed tongue are from the bamboo honing blade
Video excerpts:
Khaen making in a village in Roi Et
province, Northeastern Thailand
Filmed in 1988 by Terry Miller
Khaen making
•
•
•
•
•
Carving the wind chamber
Beating kishut
Shaping kishut into strips
Assembling khaen
Finishing touches
Carving the wind chamber
Beating kishut
Shaping kishut into strips
Assembling khaen
Finishing touches
Complete khaen demonstrated (lai soi)
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Special session,
Acoustical Society of
America, San Diego 2011
Acoustics of Mouth
Organs
Followed by CONCERT
CONCERT
Mouth Organs East and West
Khaen:
Christopher Adler
University of San Diego
Music Department
Harmonica:
Howard Levy
5:00-6:00 p.m.
Monday, October 18
Garden Salon
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