Rob Maher Electrical amp Computer Engineering Montana State University Bozeman MT USA robmahermontanaedu Objective and Subjective Frequency Pitch Sound level Loudness ID: 1017740
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1. Lecture 31Music SynthesisRob MaherElectrical & Computer EngineeringMontana State UniversityBozeman, MT USArob.maher@montana.edu
2. Objective and SubjectiveFrequency PitchSound level LoudnessRepetition rate TempoSource Geometry LocalizationSpectrum Timbre
3. TimbreThe relative spectral energy at different frequencies is perceived as a distinct tone color, or timbre (pronounced as either tam--burr or tim-burr)Timbre: The combination of qualities of a sound that distinguishes it from other sounds of the same pitch and volumeInterest in electronically simulating desired timbres
4. Some HistoryThree distinct directions of synthesis development:Coded Performance (e.g., player piano)Direct Performance (e.g, keyboard or gestural interface)Musique Concrete (e.g., tape music)
5. ~1900: The TelharmoniumThaddeus Cahill, inventorUsed a series of geared electrical generators to create harmonicsBefore amplifiers: direct power transmission into homes and businesses via telephone wiresKeyboard and potentiometer controlOccupied 30 box cars and weighed 200 tons!
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7. ~1920: The ThereminLeon Theremin, inventorHigh frequency fixed oscillator (10 MHz)High frequency variable oscillator adjusted by capacitance (10 MHz)Capacitance altered by hands moved near antennae:Antenna to adjust frequencyAntenna to adjust volumeSound is audible “beat” frequency between fixed oscillator and variable oscillator
8. https://youtu.be/pSzTPGlNa5U
9. ~1928: The Ondes MartenotMaurice Martenot, inventorKeyboard instrument with resistance wirehttps://youtu.be/f4phKWMaOr0
10. ~1928: The Trautonium and MixturtrautoniumFredrich Trautwein, inventorNeon tube oscillator with resistance wire controlTouch-sensitive actionElectric filters for “formants”https://youtu.be/-tQQEChMq1A
11. ~1930: The Hammond OrganLaurens Hammond, inventorFrequencies derived from 60Hz power line frequencyTone wheels with “bumps” pass magnetic pickupsOnly 91 sine wave frequencies: all partials are equal-temperedFrequencies 1 : 2 : 2.9966 : 4 : 5.0397 : etc.Uses tremolo to eliminate mistuned and “bland” soundLeslie Loudspeaker – spinning for Doppler vibrato
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13. Hammond FrequenciesFrequency F (Hz) = M * T * RFor A4: 20 * 16 * (88 / 64) = 440HzFor C#8 = 4,434Hz: 20 * 192 * (74/64) = 4440Hz91 Hammond tone wheels12 tonewheels of 2 teeth12 tonewheels of 4 teeth12 tonewheels of 8 teeth12 tonewheels of 16 teeth12 tonewheels of 32 teeth12 tonewheels of 64 teeth12 tonewheels of 128 teeth7 tonewheels of 192 teeth M – Motor speed, 20 revs/second (1200 rpm) T – Number of teeth on the tone wheel R – The gear ratio. This is equal to the number of teeth on the driving gear / number of teeth on driven gear.
14. Leslie LoudspeakerRotating horns for high frequencies, rotating spinning drum for low frequencieshttps://youtu.be/F4XSZ1haPk4
15. ~1948: Musique ConcretePierre Schaeffer, originatorUse of sound as “found objects”Everyday sounds used as musicFirst used phonograph records for sound assembly, then tape recorders
16. ~1955: The RCA SynthesizerVacuum tube oscillatorsControlled by roll of punched paper tapeFrequency and amplitude controlsAudio output to a disc cutter
17. ~1965: Voltage Controlled SynthesizersRobert MoogARPEMSElectrocompBuchlaInitially monophonic and modular, with patch cordsLater keyboard controlled and portable
18. Wendy Carlos
19. Voltage Controlled modulesVCO – voltage controlled oscillatorVCA – voltage controlled amplifierVCF – voltage controlled filterEG – envelope generatorLFO – low frequency oscillatorSequencer – memory unit triggered by a clock
20. https://www.montana.edu/rmaher/eele217_fl18/soundfiles/Preston_spacerace.wav
21. ~1970: Computer MusicWavetable synthesis (fixed waveform)Additive synthesisModulation techniques (AM, FM, Ring modulation, waveshaping)Subtractive synthesis
22. ~1980-present:Computers as musical instrumentsMusical Instrument Digital Interface (MIDI)Software synthesisReal time recording direct-to-diskReal time mixing