Physics 1251 The Science and Technology of Musical Sound Unit 4 Session 37 MWF Synthesizers Unit 4...

Physics 1251Physics 1251The Science and The Science and

Technology of Musical Technology of Musical SoundSound

Physics 1251Physics 1251The Science and The Science and

Technology of Musical Technology of Musical SoundSound

Unit 4Unit 4

Session 37 MWFSession 37 MWF

SynthesizersSynthesizers

Unit 4Unit 4

Session 37 MWFSession 37 MWF

SynthesizersSynthesizers

Physics 1251Physics 1251 Unit 4 Session 37Unit 4 Session 37 SynthesizersSynthesizers

In your own words, describe what a In your own words, describe what a synthesizer is and what it does.synthesizer is and what it does.

A synthesizer:A synthesizer:• is an electronic device;is an electronic device;• is controlled by a player;is controlled by a player;• produces electro-acoustic produces electro-acoustic signals;signals;• simulates acoustic simulates acoustic instruments;instruments;• generates novel and unique generates novel and unique sounds.sounds.


11′ Lecture:′ Lecture:

• A Synthesizer is a player-controlled electronic A Synthesizer is a player-controlled electronic device creating electro-acoustical signals that device creating electro-acoustical signals that emulate other instruments or generate unique emulate other instruments or generate unique sounds.sounds.

• Notes played by acoustic instruments pass through Notes played by acoustic instruments pass through four phases: (1) attack, (2) decay; (3) sustain; four phases: (1) attack, (2) decay; (3) sustain; (4) release. (ADSR)(4) release. (ADSR)

• Realistic synthesis requires sound to change with Realistic synthesis requires sound to change with time in pitch, frequency recipe, and amplitude time in pitch, frequency recipe, and amplitude during the ADSR phases.during the ADSR phases.

• Synthesizers are either analog or digital.Synthesizers are either analog or digital.• Synthesizers employ either additive (or Synthesizers employ either additive (or

subtractive) synthesis or frequency modulation subtractive) synthesis or frequency modulation (FM).(FM).


80/2080/20A Synthesizer is a player-controlled A Synthesizer is a player-controlled electronic device creating electro-electronic device creating electro-acoustical signals that emulate other acoustical signals that emulate other instruments or generate unique instruments or generate unique sounds.sounds.

What does that mean?What does that mean?


80/2080/20A Synthesizer is a A Synthesizer is a player-controlledplayer-controlled electronic device creating electro-electronic device creating electro-acoustical signals that emulate other acoustical signals that emulate other instruments or generate unique instruments or generate unique sounds.sounds.

SynthesizerSynthesizer

4444 ♩♩♩♩♩♩ ♩♩ ♩♩♩♩ ♩♩

♩♩


80/2080/20A Synthesizer is a player-controlled A Synthesizer is a player-controlled electronic deviceelectronic device creating electro- creating electro-acoustical signals that emulate other acoustical signals that emulate other instruments or generate unique instruments or generate unique sounds.sounds.

SynthesizerSynthesizer

Voltage VVoltage V

Current ICurrent I

I =V/RI =V/R

Ohm’s Law: R Ohm’s Law: R =V/I=V/I


80/2080/20A Synthesizer is a player-controlled A Synthesizer is a player-controlled electronic device creating electronic device creating electro-electro-acoustical signalsacoustical signals that emulate other that emulate other instruments or generate unique instruments or generate unique sounds.sounds.

CurrentCurrentSynthesizerSynthesizer

VoltagVoltagee

++

--++

--++

-- ++

--


80/2080/20A Synthesizer is a player-controlled A Synthesizer is a player-controlled electronic device creating electro-electronic device creating electro-acoustical signals that acoustical signals that emulate other emulate other instruments or generate unique instruments or generate unique soundssounds..Synthesis or the Real Synthesis or the Real Thing?Thing?


♪ The first modern synthesizer The first modern synthesizer was produced by RCA in 1955.was produced by RCA in 1955.

♪ The Moog (rhymes with vogue) The Moog (rhymes with vogue) synthesizer was invented in synthesizer was invented in 1965 by Robert Moog.1965 by Robert Moog.

First Moog SynthesizerFirst Moog Synthesizer

AttackAttack

Physics 1251Physics 1251 Unit 4 Session 37Unit 4 Session 37 Synthesizers Synthesizers

♪♪Realistic synthesis requires emulation of Realistic synthesis requires emulation of realistic musical sounds.realistic musical sounds.

80/2080/20Musical sounds are characterized by Musical sounds are characterized by four phases: (1) attack; (2) decay; (3) four phases: (1) attack; (2) decay; (3) sustain;sustain;(4) release; abbreviated ADSR.(4) release; abbreviated ADSR.

DecayDecay SustainSustain ReleasReleasee

EnvelopEnvelop


80/2080/20Synthesizers use analog or digital Synthesizers use analog or digital processing.processing.

AnaloAnalogg


Sound Sound WavesWaves

Pre

ssu

reP

ressu

re

Volt

aV

olt

ag

eg

e


DigitDigitalal


Sound Sound WavesWaves

Pre

ssu

reP

ressu

re

Digital:Digital:

10001000010001000010001000010001

80/2080/20The amplitude of The amplitude of the waveform is the waveform is digitized and digitized and expressed as a binary expressed as a binary number.number.

Digital to Analog Conversion (DAC)Digital to Analog Conversion (DAC)


000000110010010001001000

10010000

10110100

11

22

44

88

DAC DAC (Concept)(Concept)1101101100100111

Electronic Digital-to-Analog Electronic Digital-to-Analog ConversionConversion1 1 0 1 1 0

001 1 1 1 1 1 001 1 1 1 1 1 111 0 0 1 0 0 111 1 1 1 1 1 001 0 0 1 0 0 110 1 1 0 1 1 000 0 0 0 0 0 000 0 0 0 0 0 110 0 1 0 0 1 111 1 0 1 1 0 000 1 1 0 1 1 000 0 1 0 0 1 110 0 0 0 0 0 110 0 0 0 0 0 00


Input Input NumberNumber

Output VoltageOutput Voltage


Additive Synthesis:Additive Synthesis:• The output signal is built up from a sum The output signal is built up from a sum

of harmonic signalsof harmonic signals..

ΣΣ


Frequency Modulation (FM) Frequency Modulation (FM) Synthesis:Synthesis:

• In FM Synthesis the frequency fIn FM Synthesis the frequency foo of of the signal is modulated up and down the signal is modulated up and down with a frequency fwith a frequency fFM FM . The vibration . The vibration recipe contains peaks at recipe contains peaks at ffoo ∓ n f∓ n fFM FM ..

If fIf fFMFM = f = foo , then one , then one produces a harmonic produces a harmonic series, f = m fseries, f = m foo . .

Voltage Voltage Controlled Controlled Oscillator Oscillator (VCO)(VCO)

ffFMFM

ffoo


Summary:Summary:• A Synthesizer is a player-controlled electronic A Synthesizer is a player-controlled electronic

device creating electro-acoustical signals that device creating electro-acoustical signals that emulate other instruments or generate unique emulate other instruments or generate unique sounds.sounds.

• Notes played by acoustic instruments pass Notes played by acoustic instruments pass through four phases: (1) attack, (2) decay; (3) through four phases: (1) attack, (2) decay; (3) sustain; sustain; (4) release. (ADSR)(4) release. (ADSR)

• Realistic synthesis requires sound to change with Realistic synthesis requires sound to change with time in pitch, frequency recipe, and amplitude time in pitch, frequency recipe, and amplitude during the ADSR phases.during the ADSR phases.

• Synthesizers are either analog or digital.Synthesizers are either analog or digital.• Synthesizers employ either additive (or Synthesizers employ either additive (or

subtractive) synthesis or frequency modulation subtractive) synthesis or frequency modulation (FM).(FM).

Physics 1251 The Science and Technology of Musical Sound Unit 4 Session 37 MWF Synthesizers Unit 4...

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