MUSIC 318 PLUCKED STRING INSTRUMENTS
HARPSICHORDS
AND CLAVICHORDS
SCIENCE OF SOUND, CHAPTER 14
PHYSICS OF MUSICAL INSTRUMENTS, CHAPTER 11
“ANALYSIS OF THE DESIGN AND PERFORMANCE OF HARPSICHORDS”
(N.H.FLETCHER, ACUSTICA 37, 139 (1977).
HISTORY
THE IDEA OF USING A KEYBOARD TO CONTROL THE PLUCKING OF STRINGS SEEMS TO
HAVE DEVELOPED IN THE LATE 14TH CENTURY, WITH A HARPSICHORD-LIKE
INSTRUMENT APPEARING IN THE 15TH CENTURY. MOST OF THE DEVELOPMENT
OF THE HARPSICHORD TOOK PLACE IN THE 16TH AND 17TH CENTURIES, FIRST IN
ITALY AND THEN IN FLANDERS, GERMANY, AND ENGLAND.
HARPSICHORDS MAY HAVE ONE OR TWO KEYBOARDS, AND EVEN A PEDAL
KEYBOARD (SIMILAR TO A PIPE ORGAN). PLASTIC PLECTRA HAVE NOW LARGELY
REPLACED THE TRADITIONAL QUILLS.
IN ADDITION TO THE STANDARD
HARPSICHORD IN WHICH THE STRINGS RUN
STRAIGHT AWAY FROM THE PLAYER, THERE
ARE TWO SMALLER VERSIONS USING THE
SAME PLUCK ACTION. ONE, KNOWN AS THE
VIRGINAL HAS A RECTANGULAR CASE WITH
THE STRINGS RUNNING NEARLY PARALLEL TO
THE KEYBOARD. ANOTHER KNOWN AS THE
SPINET, HAS A TRIANGULAR CASE WITH THE
STRINGS RUNNING OBLIQUELY TO THE
KEYBOARD.
HARPSICHORD
MODERN FLEMISH
HARPSICHORD BY AUSTRALIAN
CAREY BEEBE BASED ON
CLASSICAL INSTRUMENTS BY
THE 17TH CENTURY MAKER
ANDREAS RUCKERS.
THE KEYBOARD COMPASS HAS
BEEN EXTENDED DOWN TO G3
IN THE BASS AND UP TO D6 IN
THE TREBLE.
THE SMALL PROTRUSIONS ON
THE RIGHT SIDE (CHEEK)
ENABLE THE PLAYER TO
ENGAGE EITHER OF THE TWO
SETS OF JACKS BY SLIDING THE
REGISTER ON OR OFF
HARPSICHORD ACTION (SIMPLIFIED)
HARPSICHORD ACTION
EACH JACK PASSES THROUGH A SLOTT END UPPER REGISTER AND A LOWER GUIDE, AND
THE PLAYER CAN MANIPULATE THE UPPER REGISTER TO MOVE THE WHOLE SET OF JACKS
SO THE PLECTRA ARE JUST OUT OF RANGE OF NORMAL PLUCKING CONTACT WITH THE
STRINGS THAT DO NOT SOUND.
HARPSICHORD ACTION
ACTION OF A FLEMISH HARPSICHORD. IN THIS INSTRUMENT THERE ARE TWO CHOIRS
OF STRINGS, THE SHORTER 4-FT CHOIR AND AN 8-FT CHOIR. THE LEATHER PADS OF THE
BUFF STOP ARE VISIBLE BEHIND THE 4-FT TUNING PINS
SCALING
THE FUNDAMENTAL FREQUENCY OF A VIBRATING STRING DEPENDS UPON ITS
T
LENGTH, DIAMETER, AND TENSION, AND MASS PER UNIT LENGTH: f  1 
 
2

Lm

THE UPPER STRINGS ARE NORMALLY MADE OF IRON AND THE
LOWER ONES OF BRASS, WHICH IS MORE DENSE.
1
/2
SCALING OF STRING SOUND LENGTH, PLUCKING POSITION, AND STRING DIAMETER FOR
THE 8-FT AND 4-FT STRING CHOIRS OF RUCKERS REPRODUCTION
HARPSICHORD SCALING
SCALING OF STRING DIAMETER FOR 4-FT AND 8-FT STRING CHOIRS
POINT OF PLUCKING EACH STRING
A MAJOR DESIGN FEATURE IS THE POSITION AT WHICH EACH STRING IS PLUCKED. IF
A STRING IS PLUCKED AT A POSITION 1/n OF ITS LENGTH FROM ONE END, THERE IS
A STRONG DOWNWARD FORCE FOR A FRACTION 1/n OF A PERIOD, FOLLOWED BY A
MUCH WEAKER UPWARD FORCE FOR THE REMAINDER OF THE PERIOD.
HARMONICS BELOW THE nth ARE STRONG, THE nth HARMONIC IS MISSING, AND
HARMONICS ABOVE THE nth DECREASE WITH INCREASING FREQUENCY.
STRING FORCE ON THE BRIDGE
WAVEFORM OF BRIDGE FORCE FOR PLUCKING AT 1/5 THE STRING LENGTH (a) AND 1/20
OF THE LENGTH (c). SPECTRA ARE SHOWN IN (b) AND (d)
STRUCTURE
STRINGS TRANSMIT VIBRATIONAL ENERGY TO THE SOUNDBOARD BY MEANS OF THE
BRIDGES. THE SHAPES OF THE MODES OF VIBRATION OF THE SOUNDBOARD ARE
INFLUENCED BY THE OVERALL SHAPE AND STIFFNESS, AND BY THE RIBS AND BRIDGES
ATTACHED TO IT. THE ENCLOSED AIR ALSO STRONGLY INFLUENCES THE MODES OF
VIBRATION, AND RADIATES CONSIDERABLE SOUND THROUGH THE ROSE HOLE.
VIBRATIONAL MODES OF A HARPSICHORD SOUNDBOARD
SOUND QUALITY AND DECAY TIME
DECAY TIMES FOR RUCKERS HARPSICHORD
CLAVICHORDS
COPY OF A DOUBLE-FRETTED CLAVICHORD MADE IN THE 18TH CENTURY BY CHRISTIAN
HUBERT. THE BRIDGE IS MOUNTED ON A THIN SOUNDBOARD WHICH FORMS THE TOP
OF A CAVITY
CLAVICHORD ACTION
EACH KEY IS PIVOTED ON THE BALANCE RAIL AND WHEN IT IS DEPRESSED, THE BRASS
TANGENT STRIKES THE PAIR OF STRINGS CORRESPONDING TO THAT NOTE.
STRING LENGTHS AND DIAMETERS OF CLAVICHORD
STRINGS FROM C2 TO F#2 ARE OF RED BRASS ® AND ALL OTHER STRINGS ARE
OF YELLOW BRASS (Y)
CLAVICHORD SOUND
UNLIKE THE HARPSICHORD, THE CLAVICHORD PLAYER HAS DIRECT DYNAMIC CONTROL
OVER THE SOUND BY VARYING THE SPEED AT WHICH THE TANGENT STRIKES THE STRING
AND THE FORCE WHILE THE SOUND IS SUSTAINED. THE FORCE ON THE BRIDGE HAS A
SPECTRUM THAT FALLS SMOOTHLY AT ABOUT 8 dB/OCTAVE. BECAUSE THE
DISPLACEMENT OF THE STRING BY THE TANGENT INCREASES ITS TENSION BY A SMALL
AMOUNT, THE PLAYER CAN CREATE A PITCH VIBRATO BY VARYING THE FINGER FORCE ON
THE KEY.
THE FACT THAT EACH NOTE IS PRODUCED BY TWO STRINGS PRODUCES AN EFFECT
SIMILAR TO THAT FOUND IN PIANOS. IMMEDIATELY AFTER STRIKING, THE STRINGS
VIBRATE IN PHASE, AND VIBRATIONAL ENERGY IS TRANSFERRED RAPIDLY TO THE BRIDGE
AND SOUNDBOARD, LEADING TO A RAPID INITIAL SOUND DECAY WITH AN
“AFTERSOUND” AFTER THE TWO STRINGS GET OUT OF PHASE. THIS LEADS TO AN
INITIAL CLARITY OF SOUND COMBINED WITH A MELLOWNESS.