Lecture # 23 Sound Synthesis & Sound Arithmetic

A “ sound font ” dog Jane knows Fred Ralph the loves Jane lovesFred

MIDI - Musical Instrument Digital Interface Object representation of music Every sound has –Pitch (frequency of the sound) –Delay (how long after last sound start to start playing) –Duration (how long should it play) –Timbre (which instrument should it sound like?) Guitar Clarinet Violin

A MIDI file An array of notes 0 (262, 0,10,1) 1 (300, 10,10,1) 2 (262, 10, 10, 1) 3 (300, 0, 10, 1) Pitch (middle C) Delay Duration Instrument Number During performance numbers are assigned to different instruments

MIDI demo

A MIDI file An array of notes 0 (262, 0,10,1) 1 (300, 10,10,1) 2 (262, 10, 10, 1) 3 (300, 0, 10, 1) How do we transpose to a higher key? Increase pitch of each note

A MIDI file An array of notes 0 (262, 0,10,1) 1 (300, 10,10,1) 2 (262, 10, 10, 1) 3 (300, 0, 10, 1) How do we make it play faster? Reduce delay and duration of each note

A MIDI file An array of notes 0 (262, 0,10,1) 1 (300, 10,10,1) 2 (262, 10, 10, 1) 3 (300, 0, 10, 1) How do we change from guitar to flute? Assign a different instrument to that number

Synthesizing an instrument Mix different harmonics Add noise Adjust Attack, Dwell, Sustain, Release

Synthesizing an Instrument Attack - when string is plucked or note is struck Dwell - energy left from attack Sustain - while the note is held Release - after player stops

Synthesizing an Instrument Attack - when string is plucked or note is struck Dwell - energy left from attack Sustain - while the note is held Release - after player stops

Synthesizing an Instrument Attack - when string is plucked or note is struck Dwell - energy left from attack Sustain - while the note is held Release - after player stops

Synthesizing an Instrument Attack - when string is plucked or note is struck Dwell - energy left from attack Sustain - while the note is held Release - after player stops

Synthesizing an Instrument Attack - when string is plucked or note is struck Dwell - energy left from attack Sustain - while the note is held Release - after player stops

Sampled / Object Sampled Jane loves Fred Object

Sound Editing and Processing with Audacity

Edit Sound Drag and Drop (universities-deep_thoughts.wav) File >> Import >> Audio –Notice new track (two if it is stereo) File >> Import >> Audio (theknack.wav) –Notice second track Select Track Select Time Shift action Move Track Mix and Render (“barnyard”: cow, horse, duck) Play/Mute/Align Undo (Cntrl-Z)

Edit Sound Split Align Select All Import Dance Music Trim Shape Record Sing a round/Play around Amplify/ Distort Blend Arithmetic with Sounds

Arithmetic on Sound Sound is an array of amplitudes (numbers) The higher the amplitude, the louder the sound –Adding two sounds together –Make a sound louder or softer –Blends of two sounds –Echos

Adding two sounds Laser Guns Distress + = New Sound

Adding two sounds Algorithm Laser = laser gun sound; Warn = warning message; NewSnd = new array(Laser.length); for (each index i in NewSnd) {NewSnd[i]=Laser[i]+Warn[i]; }

Adding Sounds Demo Drag or manufacture 2 or more track –Play –Shift –Mix and Render

Making a sound louder

Amplify Sound Demo –Effects -> Amplify

Making a sound louder for (each index i in oldSound) {newSound[i]=oldSound[i]* 3 ; }

General Amplify algorithm amp = 3.0; three times as loud for (each index i in oldSound) {newSound[i]=oldSound[i]* amp ; }

General Amplify algorithm amp = 0.5; half as loud for (each index i in oldSound) {newSound[i]=oldSound[i]* amp ; }

Blending two sounds Music Words 50% music, 50% words

Blending Sounds Demo 2+ Tracks -> Effects -> Amplify –Tracks -> Mix Render

Algorithm for Blending two sounds B = blend value between 0.0 and 1.0 for (each index i in Snd1) {newSnd[i]=(1.0-B)*Snd1[i]+ B*Snd2[i]; }

Singing a Round by yourself Row Row Row your boat Sing in a round

Singing a round by yourself Time delay + =

Singing a round by yourself Demo 2+ tracks -> align/shift/paste –Tracks -> Mix Render

Singing a round by yourself song = the original song; delay = how many samples to delay; newSng = new array(song.length+delay); for (each index i in song) {newSng[i] = song[i]; } for (each index i in song) {newSng[i+delay] = newSng[i+delay]+song[i]; }

Echoes An echo occurs because sound returns delayed and softer after bouncing off of something Original Canyon Echo (large delay) Room Reverb (small delay)

Echoes Demo Audacity –Effects -> Echo

Echoes Algorithm sound = the original sound; delay = how many samples to delay; softness = 0.1; newSound = new array(sound.length+delay); for (each index i in sound) {newSound[i] = sound[i]; } for (each index i in sound) {newSound[i+delay] = newSound[i+delay] + sound[i]*softness; }

Review Sound Synthesis (MIDI, timbre, pitch, etc) Change Pitch Change Tempo Change Speed