ChordophonesTradeoffs in chordophones Strings onlyPiano spectrumAre these frequency shifts important?Loose stringsBass stringsSoprano stringsTradeoffs in the stringsAmplification:Amplification (continued)Violin spectrumCello spectrumOpen strings vs fingered on violinGuitar spectrum and decayPiano ActionModern Piano ActionStretched octaves and string non-linearity – Railsback curveString decay ratesComposers write for available instrumentsExamples of Chordophones Box Zither- Santoor IndiaVietnamese Board ZitherClass projects 2005 , beforeAfrican Lute ChadTar: Lute from AzerbaijanHarp –ngombi Central AfricaKora-GuineaMbela- Musical Bow Central AfricaRole of sustain in varying how plucked instruments are playedSounding the stringHammered/Plucked/BowedAmplification via PickupsMagnetic pickupsContact PickupsAir pickupsChordophonesPhysics of Music PHY103Tradeoffs in chordophonesStrings only•High tension means a lot of stress on the instrument.•More massive strings have lower pitches under lower tension•However thick strings don’t bend very easily –Loss of high frequencies leading to dull or soft timbre.–Shift of overtones sharpwardsPiano spectrum347Hz 697Hz 1396Hz 1094Hz Higher harmonics are higher than multiples of fundamentalWhy? Wave equation requires more energy for shorter waves – non-linear wave equation on string347*2=694347*3=1041347*4=1399Are these frequency shifts important?Butler(example 2.4).a) Piano playing C4b) Piano playing C4 but the partials have been lowered by digital processing so that their frequencies are exact integer multiples of the fundamental. Pair of tones repeated 3 times.Loose strings•Violin D string tuned to an A?•bowed and pluckedBass strings•If you lower the tension too much the tension changes during plucking or hammering. The pitch changes after the pluck. The strings flop around leading to buzzing and fast damping. Low notes then requires thick and heavy strings (metal ones) to prevent these problems.•Wound strings help reduce problem of loss of high frequencies. Problems with wound strings: damage to fret-board and fingers particularly for fretless basses.•To keep corrosion from reducing high frequency response  plastic covering. However stretching of plastic may damp string motion faster.•If the tension is too low then the string will hit the finger board. This is less of a problem for a harp but is a big problem for a guitar or lute.Soprano strings•Require light strings and high tension (for a given tension).•Metallic strings are tiny and kill your fingers. Many steel string lutes/guitars are not plucked by hand.•Gut or nylon strings are softer but damp faster and are less bright.Tradeoffs in the strings•Length/tension/density – ease of play, position of plucking, having strings of different notes on the same keyboard or fret-board, strength of instrument.•String composition – metallic – less damping but heavier, harsher and more damaging to fingers and fret-boards– Gut or nylon – softer/duller but lighter and damping fasterAmplification:•A string by itself is not a very good radiator – it has a small surface area.•To increase volume the vibration must be coupled to something with a larger surface area.•Box: guitar/zither - vibration passes through bridge– faces of the box vibrate.•The surfaces of the box vibrate in modes as does the air inside.Amplification (continued)•Box with holes – air moves in and out(violin, guitar)•Box with a membrane (African lutes) vibrations excited in the membrane too.The string excites harmonics, some are amplified more than others depending on the coupling of the string to box and the way the box resonates.Violin spectrumnote the envelope!spectrum is remarkably harmonicCello spectrum•Again note envelopeOpen strings vs fingered on violin•open string has stronger high frequency harmonicsGuitar spectrum and decayAt different timesPiano Action•While the 88 key board had been fully developed in the 15th century the “piano-forte” action was introduced by Christofori in the early 18th century. •Originally hammers were covered with soft leatherModern Piano Action•Modern piano action is modeled after Crhistofori’s.•Pianists criticize electric keyboards and pianos because they fail to have the sensitivity and response of the piano actionStretched octaves and string non-linearity – Railsback curveString decay rates•The more strings, the louder the sound.•Coupling between strings can influence how sound is transferred to soundboard •Slower decays with 2+ stringsComposers write for available instruments Moonlight Sonata Beethoven •Evgeny Kissin playing a modern Steinway•Gayle Martin Henry playing a piano from around 1805 by the Viennese maker Caspar KatholniThis clip from: http://www.slate.com/id/2245891/the comparison from the posted article by Jan Swafford! Modern pianos have bigger keyboards, longer sustain and more uniform timbre across registersComposers used the longer sustain and differences in timber as effectsExamples of ChordophonesBox Zither- Santoor India•Box zither – trapezoid box with many parallel strings, strings are struck•Santoor (Indian)Music taken from CD Musical instruments of the World 1990 CNRSVietnamese Board Zither•16 steel strings above an oblong convex sound box.•Strings are plucked and pressed to change the pitchClass projects 2005 , before•little koto•washtub bassAfrican LuteChad•Skin below the strings on the gourd.•Gourd resonatorTar: Lute from Azerbaijan•Belly is covered with ox pericardium membrane•24 movable frets of gut?Harp –ngombi Central Africa•plucked soft gut stringsKora-Guinea•ox tendon strings slid up and down for tuning•notched bridgeMbela- Musical Bow Central Africa•What is the resonant cavity?Role of sustain in varying how plucked instruments are played•Metallic strings with long sustain must be damped, harder to play (use pluckers)•Gut strings with short sustain are strummed rapidly with fingersSounding the string•Plucking finger/plucker Sound is influenced by position of plucker•Hammering Sound is influenced by weight of hammer, material of hammer and leverage of hammer.•Bowed –stick/slip continuous excitation. Ability to control sound quality during the entire toneFor plucked and hammered tones, there is no control after the note soundsHammered/Plucked/BowedWhich one is which and how might you expect the sound