Multiphonics and the Oboe

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Multiphonics
and the
Oboe
supplementary
notes

Paul Archbold
&
Christopher Redgate

2

Multiphonics and the Oboe: supplementary notes
1. What is a multiphonic?
2. Different types of multiphonics
2.1 Spectrogram of a consonant multiphonic and a dissonant multiphonic 2.2 Spectrogram of a beating multiphonic
2.3 Spectrogram of an emerging multiphonic

2.4Spectrogramoffivemultiphonics,createdwithamodificationtothetopbkey 3.Differentinstruments,differentmultiphonics
4. Commentaries on music extracts:
Roger Redgate
Ausgangspunkte

EdwinRoxburgh
Antares
Paul Archbold
a little night music
Heinz Holliger
Studie über Mehrklänge (Study in Multiphonics)
5. Notation strategies

5.1Someobservationsonthevariousmethodsofnotatingmultiphonics 6.Somegeneraladviceforcomposers
7. Bibliography

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1. What is a multiphonic?
Amultiphonicisasonorityproducedonawindinstrument,whichisperceivedasamixtureof severaltones.
Whenawindinstrumentproducesanoteperceivedasasinglepitch,aspectralanalysis1 of the notewillrevealseveralpartials.Thefrequenciesofthesepartialswillberegularlyspacedandwill formpartofaharmonicseries:i.e.thefrequenciesofthepartialswillallbeintegermultiplesofa ‘fundamental’frequency.

Withamultiphonic,thesonorityisperceivedasseveralpitches. Inthecaseofadissonantmultiphonic,aspectralanalysiswillrevealseveralpartials,the frequenciesofwhicharenotintegermultiplesofacommonfundamentalfrequency.Theear groupsthepartials,witheachgroupsuggestingadifferentfundamentalfrequency.Soadissonant multiphonicwithsay20prominentpartialsmaybeperceivedasamixtureofthreedistinctpitches. Inthecaseofaconsonantmultiphonic,aspectralanalysiswillrevealseveralpartials,the frequenciesofwhichareintegermultiplesofacommonfundamentalfrequency.However,the amplitudesofsomeofthepartialsaregreaterthanusual,sotheearinterpretsthesonorityasa combinationofmorethanonepitch-e.g.aconsonantintervalsuchasaperfectfifth. Inthecaseofabeatingmultiphonic,theearcannotdiscriminatethepartialsthatareveryclose together.However,theeardoesperceiveanoverallperiodicfluctuationinamplitudeofthe sonoritywhichisinterpretedasa‘beat’.

Multiphonicsarenotpredictedbysimplemodelsofconicaltubesexcitedbyareed.However, morerecentscientificinvestigationshaverevealednon-linearitiesinthebehaviorofthedoublereedandmorecomplexphysicalmodelsoftheoboehavesuggestedcomplexinteractions betweenboreshape,holedesign,keyworkandthedoublereed2. Some recent computer synthesisersimplementingphysicalmodelscanproducemultiphonic-likesonorities3.

1.

2.

3.

AllthespectralanalysesincludedinthesenoteswereprocessedwiththeIRCAMsoftwareprogram

Audiosculpt(v2.9.2).Thesettingsusedwere:audiosamplingrate44.1kHz,windowsize2048samples, adaptiveoversampling8*,windowtypeBlackman,FFToversampling1* Foramathematicalanalysisofthecomplexinteractionsinadouble-reedinstrumentsee AndréAlmeida,ChristopheVergez,RenéCaussé,XavierRodet‘Physicalmodelofanoboe:comparisonwith experiments’

TheYamahaVL-1,amonophonicphysical-modellingdigitalsynthesiserlaunchedin1994,wasoneofthe firstcommerciallyavailablesynthesisersabletoproducemultiphonic-likesoundsusingaphysicalmodelof theflute,controlledwithashortpianokeyboardandabreathcontroller.Sophisticatedvirtualinstrumentscan becreatedintheIRCAMsoftwarepackageModalysusingphysicalmodelswhichcancreatemultiphonic-like sonorities.However,itisnotclearthatthesemodelsproducethesamesoundasaprofessional

woodwindinstrumentandplayerusingequivalentvirtualfingerings.

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