271b-1a-mar31.mp4: Meeting 1a, March 31, 2021

0:00 the electronic music repertory
1:00 part 1: early computer music
5:00 part 2: audio recordings as medium
7:00 the tape music era (1943-2000 perhaps)
8:30 part 3: algorithmic music
16:30 Outliers: Wendy Carlos and Maryanne Amacher
19:30 organization of the course (send me e-mail about what interests you)
23:00 Patches to use: the Pure Data Repertory Project: 
25:00 PDRP documentation
28:30 Example: running patch for John Chowning, Stria
31:30 about the Stria patch (not a realization, just a study patch)
32:00 FM (frequency modulation) synthesis
33:00 sinusoids and FM sound at A440
34:30 FM ratio (modulation frequency to carrier frequency)
37:00 FM spectrum
37:40 main out and mute controls.  Gain units for main out
39:30 spectrum of very slowly changing frequency tone
40:00 index controls range of frequency deviation.  Phase modulation
40:30 if using phase modulation, index adds bandwidth
42:30 frequency resolution of ears and of FFT-measured spectra
43:30 bandwidth (spread) is product of index and modulation frequency
44:30 faster modulation gives distinct spectral peaks
47:00 modulating frequency controls separation of peaks but not amplitude
48:00 index changes the amplitudes but not the frequencies
49:30 when index is 0.38 center frequency drops out.  (it bobs in and out)
51:30 using simple fractions as FM ratios (example, 1/4: periodic tone)
54:00 golden ratio as FM ratio (non-periodic)
56:00 spacing between peaks (reflection of negative frequencies)
56:00 Helholz theory of consonance and dissonance for periodic tones
57:30 musical fifth (7 half tones)
59:00 beating between common partials that almost coincide
1:02:00 making the interval sour
1:03:30 filtering to hear the individual harmonics
1:04:00 caution abut gain while filtering sounds
1:05:00 perfect fifth (7.02 hald steps)
1:06:00 tritone (dissonant interval: pairs of partials within a critical band)
1:08:30 tempered major triad
1:10:00 near-perfect triad (-3.16 and -7.02 half-steps)

271b-1b-mar31.mp4: Meeting 1b, March 31, 2021

0:00 Stria by John Chowning
1:00 first tone in stria, imitated using the patch
2;00 beginning of real piece
6:30 time proportions in the piece
9:00 the pre-stored sequence in the patch
10:00 more faithful reconstruction from Huddersfield
12:00 theory: using the golden ratio as an FM ratio
14:00 geometric construction of golden ratio
17:00 r-1, 1, r, and r+1 in geometric progression (same interval 3 times)
22:00 Fibonacci sequence and golden ratio related
24:30 spectrum of FM with golden ratio of modulation to carrier frequency
25:00 stacking three golden FM spectra
26:00 musical scales with different octave ratios and octave divisions
28:00 spectrum of four tones separated by golden ratio
29:00 three golden ratios sound almost like 2 octaves
32:00 same interval is less sour if we use golden-ratio spectra
34:00 spectrum of four tones separated by golden ratio sounds consonant
37:00 1/3 of an octave (if an octave is golden ratio)
40:00 major tetrad in 12-tone scale, sounds sour if using golden ratio spectra
41:30 (0,3,6,9) tetrad plays role of major tetrad in Stria
42:30 dividing 2:1 octave in other numbers of steps, playing (0,4,7,12) chord
43:00 quarter tones (2:1 divided in 24, or tritone divided by 12)
48:30 how many steps to divide "octave" into
53:00 how the Stria example is sequenced and what the parameters mean
56:30 amplitudes in this patch are in decibels (old practice)
57:30 index of modulation units
59:30 beating modulator oscillators
1:01:30 carrier and modulation frequencies more general definition
1:04:00 layout of files in the Chowning study patch (includes a library)
1:06:00 the qlist ("cue list" or "score")
1:08:00 events in the qlist
1:10:00 cross-fade in event 2

271b-2a-apr7.mp4: Meeting 2a, April 7, 2021
0:00 How to build a piece out of the null piece 
1:30 the patches 0.pd and 1.pd (without or with a qlist stepper/sequencer)
2:30 null piece now can read input soundfiles
4:00 copying the null piece to create a new piece named "aardvark"
4:40 difference between library and score directories
6:00 controls on main window, guts hidden
7:00 keep heavy drawing tasks in subpatches you can hide to save CPU time
9:00 put together a phase modulation sound
10:00 input, DSP, and output windows are connected to control execution order 
11:00 "input1" send/receive and "output1" throw/catch
15:00 modulating oscillator
16:00 carrier oscillator split into phasor~ and cos~
17:00 controlling the two amplitudes
19:00 index of modulation is amplitude of modulating oscillator
20:00 testing the FM pair
23:00 controlling and naming the parameters with "genctl" abstraction
24:00 receive, number box, and genctl working together
25:30 sending a message to set a parameter as in a qlist
27:00 importance of choosing mousable, readable scales (units) for parameters
30:00 fourth-power curve for controlling gains
31:00 the amp4~ abstraction for controlling amplitudes or gains
34:00 controlling the index with amp4~ (later changed)
35:00 first cut at fully controllable FM pair
36:00 "stop" button resets everything (the genctl abstraction does this)
37:30 usnig MIDI units for the two frequencies
38:00 hang a number box off a control object for debugging
39:30 oops, index should use linear units, not fourth-power
40:00 fixing index to be linearly rampable
41:30 amp4~ handles ramping
43:00 genctl makes the control display progress of ramp
43:45 pitfall: sending a pair of numbers to a receiver that didn't expect it
44:30 npack to split elements of the pair
45:20 need an audio rate ramp (line~) to control index to avoid zipper noise
46:30 how to make a default ramp time
51:00 rampable frequencies (ramp in pitch, not frequency0
53:00 wrongness of linearly ramped frequencies
54:00 5-msec default frequency sweep time (vs. 20 for amplitudes)
57:30 pitch sweep working
1:00:00 testing finished FM pair
1:01:00 alternative definition of parameters to specify frequency ratio
1:03:00 controlling the FM pair from main patch
1:04:00 adding a reverberator (rev3~)
1:06:30 rev3~ parameters don't ramp (use an external control line of you want)
1:10:00 reverberator working
1:10:30 using "grab" feature to get parameter snapshot

271b-2b-apr7.mp4: Meeting 2b, April 7, 2021

1:00 Jonathan Harvey, Mortuos Plango, Vivos Voco.  Quick look at Harvey's paper in CMJ
3:45 difficulty of wielding additive synthesis in general
5:00 generating frequencies in MPVV, partials of Winchester cathedral  bell
7:30 orchestration possibilities of voices plus additive synthesis
9:00 generatong series of MPVV
11:30 sections of piece labeled by generating series
12:30 the glissandi
14:00 stable clusters at beginning and end of glisses suggest pedal tomes
16:00 Rand's technique similar but harmonic series instead of bell
17:00 piece annnounces its series at 1:00
19:00 section 2 announced by its characteristic pitch
19:45 glissandi ni the piece (distorted)
20:30 again, better (not perfect yet)
21:30 sung chord at end
24:30 about the study patch
26:45 opening the study patch
28:00 soundfile chooser to play soundfiles through patch
30:00 the patch has a built-in bell loop
31:00 the sigmund object for sinusoidal analysis
32:00 printed out peaks
33:00 oscillator bank
35:00 comparing analyzed pitches to series in CMJ paper
37:00 separate window for culling and sorting sinusoidal components
40;00 different anayses of sound are similar but distinct
42:00 bell frequencies might not really be stable (Doppler shift)
43:00 research question: what makes some spectra sweet and others ugly?
47:00 glissandi
48:00 making message boxes containing all the components
53:00 sorting components by frequency
55:00 glissing between sorted list of compinents
55:30 selecting components within a pitch range
56:00 verifying vocal chord at end of piece is taken from series
1:00:00 additive synthesis patches always enforce some writing style
1:02:00 why Harvey's piece sounds better than, say Risset's Inharmoniques
1:03:00 Latin inscription on the bell suggests the ethos of the piece

271b-03a-apr14.mp4: Meeting 3a, April 14, 2021

0:00 looking at recorded sound based techniques earlier than planned
2:00 two currents in electronic music typified by GRM and IRCAM
3:30 studio technique isn't really the opposite of real-time
4:00 study piece is James Tenney, Collage #1
7:00 instantly recognizable sound to a 1963 audience emerges in middle
8:30 study patch is tenney-collage (tenney-collage.zip on PDRP site)
9:00 no patch could do everything interesting; this one just shows some ideas.
11:45 sample rate of patch migth be different from that of recording
13:00 reading and writing soundfiles through PDRP patches
14:00 the sampler itself is in DSP subpatch usnig "clone" object
14:30 messages to "samp" play one "note" using the sampler
15:30 arguments to samp: pitch, gain, duration, sample#, onset, rise, decay
16:30 can play overlapping notes
17:30 microtonal pitches
18:00 making a cluser, several "notes" at same start time
20:00 units of gain (50 for unit gain) and pitch (MIDI, 60 for original speed)
21:00 duration in milliseconds is output duration, not duration in file
22:00 stacking 4 octaves
22:30 need for automation: potentially 1000s of individual notes
24:00 example of audtomation: phased loops
26:30 you might not want to use this in exactly this form.
27:00 period and length in the looper
30:30 timing and emveloping of sampler playback in the patch (diagram)
31:00 onset is where in recording to start
31:30 the amplitude envelope shape
33:45 output is product of envelope generator output and playback signal
34:00 rise time, "duration", and "decay" time (nomenclature is slippery)
35:30 overall length is "duration" plus "decay" time (as in a keyboard synth)
38:00 special case, duration equal to rise time
40:00 setting all three time values equal gives time-symmetric envelope
40:30 sometimes called a Hann window
42:00 why aren't rise, duration, and decay just the same parameter
43:30 you can record audio input live and sample from it
45:00 simple example of automated granular sampling
46:45 changing parameters in a loop
47:45 overlap depends on total playing time and frequency of the loop
49:00 zero rise time to find an attack in the recording
50:00 this can make clicks but we're getting away with it here
50:45 slow rise and fast decay, and vice versa
51:00 desirability of having a choice of decay shapes for more natural decays
53:00 idea: name starting locations instead of giving them numerically
55:00 digression: tanh as a saturation function, different from envelope shape
57:00 digression: using audacity to label onsets and "text" object to store them
1:00:00 another thing you can do with the patch: granular sampling 
1:01:00 exactly periodic repetition gives a tone
1:03:00 getting rid of the periodicity randomizing grain time intervals
1:05:00 diagram of periodic and aperiodic repetition of grains
1:07:00 getting random numbers 0 to 10 in increments of 1/100
1:09:00 fixed "samp" messages in message boxes aren't very flexible
1:09:30 the looper example demonstrates parametrized messages
1:10;00 should add time reversal to dolist (patch doesn't do it yet)
1:11:00 item in dolist: you can't track down a speaking "voice" to alter it
1:14:00 more dolist: this patch only does stereo in and stereo out
1:15:00 more dolist: separate streams ("tracks") of samples
1:16:45 more dolist: multichannel output and spatialization

271b-03b-apr14.mp4: Meeting 3b, April 14, 2021

0:00 aleatoric processes
4:30 making duration variable
6:00 using random time both for metronome and for duration of sample
7:00 changing playback location in time (onset)
7:30 range from 500 to 1500 (1499 to be exact)
9:00 saple rate correction seems not to be working yet
11:00 more than one dollar substitution in message boxes: "pack" object
13:00 "float" object stores first value so that it doesn't trigger "pack"
13:45 "bang" sets the pair of numbers off, and you can asynchronously set them
14:30 you can do the opposite (make "pack" output a message on either input)
17:00 random number fo r onset, range chosen to fall within guitar solo
17:45 using trigger to put number in non-first inlet of pack and trigger it
19:30 all these parameters probably need names.  Name ranges in pairs
20:00 random-onset-start and random-onset-range variables and number boxes
23:00 receives can go into control (message) version of line
24:30 default time grain of 20 milliseconds
27:00 control names for on/off and for time duration
28:00 suggestion for messages that can't ramp: use "f" to be sure of message
30:00 putting an event in a message box to start randomized-playback process
32:00 adding pitch variation
34:30 three elements to pack together now, ordered by trigger "b f b"
35:30 adding randomizer for pitch
37:00 grain of randomization should be much smaller than 1 (1/1000 here)
38:30 you might want to specify middle of random range instead of start
41:00 trying to imitate beginning of Tenney piece
44:00 how could you make this loop?
45:30 you can have multiple processes running at once
47:00 another automated patch: granular sampler
48:45 variables we'll want: pitch, timing, duration, onset
50:00 bad but effective way to replace a name systematically (random to grainer)
53:00 inter-onset interval (time delay) no longer same parameter as duration
55:00 combine pitch, onset, and duration into a "samp" message
59:00 granular synthesis result from vocal portion of recording
1:00:00 randomizing pitch variation
1:01:00 randomizing onset makes a more diffuse sound
1:02:00 oops, another process had been running, rerunning the tests
1:06:00 possibility: sampling live instruments, playing patch as an instrument
1:07:00 more possibilities: attach MIDI controllers and/or use presets
1:09:00 inside the cloned "stereo-sample-reader" patch
1:10:00 inlet for messages to start playback, issued by "clone" object
1:11:00 more capabilities of "clone"
1:13:00 how you could adapt this patch to your own ends
1:14:00 Polansky has a paper about collage #1 on his website

271b-04a-apr21.mp4: Meeting 4a, April 21, 2021

0:00 Hidegard Westerkamp's Beneath the forest floor
0:30 musique concrete and soundscape composition compared
3:00 writings and videos available about the piece 
3:30 Inside Computer Music by Clarke, Dufeu, and Manning
6:00 downloadable materials on their website including apps to explore pieces
7:00 Westerkamp's videos describing the genesis of the piece
14:30 why one recording of two ravens didn't work i nteh piece
16:00 another raven recording that proved useful
19:00 the raven recording in audacity
20:00 1/70 - second-long ululations
21:00 TaCEM app shows the layout of the entire piece
24:00 reconstruction of piece in graphical form showing recordings and processes
25:20 slowed-down raven sound in TaCEM app
27:00 reverberance extended by slowing the recording down
29:00 trying it in audacity
32:00 three separate calls used so that it doesn't sound like sampling
34:30 overall view of piece in audacity.
35:00 Raven calls dominate forst part of piece
38:00 sounds of wind, lifeforms, and water
39:00 the sound of the motorized saw answers teh raven
40:30 quiet section that recalls beginning
41:00 pitched sounds emerge in second half
44:00 other bird sounds are sources of pitched sounds
44:30 the wren recording is high-pass filtered and slowed down
45:00 7 kHz salient frequency
47:30 time stretching (just an example, not the original technique)
48:00 more faithful imitation using reverberation
49:30 related sound from in piece (but (oops) a different bird)
50:00 hovering chords not unusual in traditional tape music
51:00 treatment of rusing water with delays
53:00 spatializing stereo recordings
54:00 close microphone pair gives impression of stereo field
56:00 Westerkamp: not sampling and manipulation, but recording and processing
57:30 melodic material from thrush song
1:03:00 1990-era technology
1:04:00 pitch fields in recording-based music

271b-04b-apr21.mp4: Meeting 4b, April 21, 2021

0:00 adding to Tenney patch to imitate techniques in Westerkamp
1:30 need to filter birdsong to get clean sounds
3:00 closer look at thrush sound in audacity
5:00 start times and durations of three thrush notes
7:00 playing thrush notes in Tenney patch
10:00 wrong transposition (fixed after class)
14:00 back to filtering
18:00 butterworth low-pass and high-pass filters
19:30 testing filters with noise input
25:00 more about filters
26:30 improving on simple band-pass filter by pairing two detuned ones
31:00 frequency response of Butterworth versus simple low/high-pass filters
32:00 Butterworth filter design
36:00 three thrush notes into sampler
37:30 reverberation using rev3~ object
44:00 testing reverberator using an impulse as nput
48:00 sampler into reverberator
52:00 fix filter cutoff to match transposition
55:00 why ramp up and down over 100 msec - gain ramp as modulation
57:30 frequency response of a ramp
58:30 the faster the envelope, the higher-frequency the aliasing
1:02:00 these ramps can be slow but in other cases you want a fast one
1:02:30 to preserve the attack in a recording make rise time instantaneous
1:04:30 gating (applying a noise gate to a recording)

271b-05a-apr28.mp4: Meeting 5a, April 28, 2021

0:00 Trevor Wishart's Imago: wavesets and phase vocoders
2:00 the acousmatic musical style
2:30 same techniques as in soundscape composition but different musical style
4:00 idea of deriving a piece out of a small sonic seed: Xenakis's P/H Concrete
6:30 seed sound for Wishart: two whiskey glasses clinking together
9:00 formal approach: form imposed by cmoposer, not emerging from soundscape
10:30 characteristic acousmatic move: gathering energy and release
12:30 close look at the seed sound using phase vocoder
17:00 time-frozen decay of the sound
19:00 uses of phase vocoder in Imago
19:30 frequency shifting (might not actually be the thing found in the piece)
23:00 pitch shifting and frequency shifting contrasted theoretically
28:00 incitement: use both pitch and frequency shifting to squash a spectrum
31:30 frequency shifting (single sideband modulation) compared with ring mod
35:00 more about phase vocoder
37:30 location in source file (center of analysis window)
38:00 window size
39:00 Hann window (same envelope as in granular example from Tenney)
41:00 how the Hann window modulates the sound
43:00 spectral stamp imposed by Hann window is 4x findamental frequency wide
44:00 analyzing a sum of sinusoids: frequency resolution
45:00 2048 points (fundamental is about 24 Hz.) - 100 Hz. resolution
47:00 100 Hz. is about low A flat.
49:00 testing phase vocoder on a combination of sinusoids
54:00 what happens when the window is too small (i.e., sinusoids too close)
56:30 fundamental tradoff: time resolution versus frequency resolution
1:00:00 two frequencies in seed sound, 1763 and 1863
1:04:00 time stretching using the phase vocoder patch
1:06:00 why the phase vocoder sounds spacy (or phase-y)
1:07:00 phase locking.  Frequency domain is separated into "bins"
1:13:00 phase vocoder on speech
1:16:00 speech stretched usnig very short analysis window

271b-05b-apr28.mp4: Meeting 5b, April 28, 2021

0:00 more about phase vocoder: compared with reverberation
8:00 vibrato via pitch shifters
9:00 2700-ish frequencies can be made to sound like a vocal formant
11:00 waveset manipulation (specifically waveset duplication)
18:00 Two Women, Four Voices: simpler examples of Wishart's techniques
19:00 part 3 (Ian Paisley): phase vocoder.  Vibrato and also too-small windowing
20:00 part 2: waveset duplication on Diana's voice
24:00 waveset duplication tested on two sinusoids
26:00 controls: minimum number of repetitions and minimum waveset length
34:00 high frequencies can re-emerge as formants
36:00 waveset duplication tested on Diana's voice
36:30 waveset duplication compared to wavetable oscillation
39:00 other waveset operations (not ready in this patch)
40:00 waveset substitution
42:00 waveset averaging
44:30 waveset duplication on seed sound
48:00 time-stretched seed sound through waveset duplication
52:00 why waveset duplication sometimes puts out higher pitches
58:00 Wishart's emphasis on hearing the source sound rather than the technique
1:02:00 even though the form is classical, result is guided by what he finds
1:05:00 Composer's Desktop Project (CDP), well-established software
1:06:00 using phase vocoder to shape envelope

271b-06a-may5.mp4: Meeting 6a, May 5, 2021

0:00 Natasha Barrett, Little Animals and (mostly) The Lock, from Hidden Values
3:00 debts to Dennis Smalley, Jonty Harrison, (early) Trevor Wishart
8:00 "wav" and "aiff" can't hold long soundfiles with many channels
10:00 classig GRM-ish sounds in Little Animals
11:30 sound projection - technique/style in which a stereo tape is spatialized live
13:30 realistic-sounding, "present" images in stereo recordings
16:00 foreground and background layers
17:00 resonant filterbanks.  Another example from Noanoa by Saariaho
19:00 The generating flute multiphonic
21:30 tradition (or trope) of discursive sounds against a static pitch field
24:00 The Lock avoids many electroacoustic-music tropes and keeps others
24:30 pitch fields in The Lock made by time-stretching and filtering the voice
27:00 spatialization is central to Hidden Values
28:30 spatial paths in concert with musical gestures and timbral evolutions
31:00 Barrett shows her setup in video from TaCEM
32:30 IRCAM spatializateur ("spat") 2 views of spatial paths
34:00 Nuendo DAW feeding 32(?) channels into IRCAM spat via jack
36:00 acousmatique-style spatial projection is not same as cinematic spatialization
36:30 cinematic-style hearkens back to Stockhausen in the 1950s
37:30 angle cues via panning and distance cues via filtering and reverberation
38:30 John Chowning's paper The Simulation of Moving Sound Sources
40:00 three approaches to cinematic spatialization: Ambisonics, VBAP, and WFS
42:00 VBAP (Vector based amplitude panning)
43:00 VBAP simulates direction but not distance of a virtual source
45:00 cinematic spatialization as used to simulate moving sources
46:30 Gestalt "common fate" grouping to fuse different source sounds
47:00 this is described in Four Criteria of Electronic Music by Stockhausen
49:00 Barrett placing three sounds spread out in space but moving together
50:30 simulating distance on top of VBAP
53:00 Ambisonics as a way to represent a local sound field (not cinematic)
54:30 to fully represent the sound field in a room takes about a million speakers
57:00 a soundfield is a superposition of plane waves in all directions
58:00 at a single point there are only 4 independent channels
58:30 but humans pick up more about the sound filed than from a single point
59:30 two-dimensional ambisonics as a function of time for every direction
1:01:00 if you sample the possible directions you get a Nyquist-like cutoff
1:02:00 to first order: DC and first-harmonic sinusoid around a circle
1:03:00 "radiation patterns" for ambisonics: omni and figure-eights
1:04:00 weighted sums of three basis patterns to make others such as cardioid
1:05:00 you can theoretically record first-order sound field at a single point
1:06:00 recording and playing back first-order Ambisonic signals
1:08:00 Ambisonic channels are in (or 180 degrees out of) phase (no delays)
1:10:00 issues of polarity and diffuse-ness in Ambisonic reproduction
1:12:00 higher-order Ambisonics.  Second-order requires 5 channels
1:13:00 equivalent to sampling the circle of directions into 5 points
1:14:00 linearity of Ambisonics allows superposition of sound fields

271b-06b-may5.mp4: Meeting 6b, May 5, 2021

0:00 Wave field synthesis (WFS)
2:30 imagining a faraway sound source heard through a series of open windows
3:30 special case: all sources ("windows") get the same signal
5:00 beam width depends on wavelength of sound and total width of source array
6:00 side-beams (additional directions of radiation)
8:00 spacing of speakers matters and should be a wavelength or less
9:00 aliasing in the angle of radiation depends on individual speaker spacing
10:30 projecting at an angle requires that you delay the signals in the speakers
13:00 requirement to avoid spatial aliasing
14:30 true WFS would require a speaker every 1/2 inch
16:00 WFS can theoretically simulate a sound source inside the listening area
17:00 VBAP and Ambisonics can only simulate faraway sources
18:00 one-dimensional wavefield arrays actually output cylindrical waves
19:00 OK, you could use a pizza-box shaped listening space
21:00 problems that arise when audience is dispersed in a listening space
23:00 problems when panning to simulate virtual sources between speakers
25:00 yet another problem: Hass (precedence) affect
29:00 in extreme case, one foot off-axis can cause Hass trouble
31:00 Ambisonics seems to get a larger listening sweet spot than VBAP
32:00 but directionality is more diffuse (less clarity of image)
34:00 highly present sounds of traditional acousmatic music benefits from "projection"
35:00 summary: advantages and disadvantages of VBAP, WFS, and Ambisonics
39:00 implications for listening to music in listening spaces in the future
40:00 binaural reductions of loudspeaker spatialization
41:00 how binaural spatialization works
43:00 head-related impulse responses and transfer functions (HRTFs)
45:00 spatial perception requires freely moving head
47:00 the ORTF mic setup
48:00 mixing an ORTF pair to a monaural signal
50:30 why worry about cinematic spatialization at all?
51:00 example: Janet Cardiff's 40-voice motet
52:00 octagonal loudspeaker arrays frequently used in electronic music concerts
53:30 affordance: clarity from separating "voices", moving or not
55:00 concert halls blur out details of amplified sounds
58:00 music in front of listener versus music played from behind
59:00 suggestion: put speakers and live musicians on stage together
1:02:00 more on Barrett, The Lock - the nature of the sound sources
1:02:30 TaCEM screen showing geneologies of materiels
1:04:00 processing is mostly time stretching, filtering, and reverberation
1:06:00 electroacoustice-style pitch fields easy to make beacuse of source
1:08:00 spatial separation to enhance clarity
1:09:00 apparently used all three spatialization models for IRCAM performance
1:10:00 Spatialisateur used to simulate binaural recording of loudspeakers via HRTFs
1:11:00 advantages: no room reverberation, and listener is in sweet spot
1:13:00 simple, arcing spatial paths
1:16:00 binaural spatialization better at sides than front

271b-07a-may12.mp4: Meeting 76a, May 12, 2021

0:00 Laurie Spiegel, Appalachian Grove
1:00 Groove system at Bell Labs - computer controlled analog electronics
2:00 this was Mathews's first foray into real-time computer music
3:00 genesis and design of "hybrid" studios
5:00 related to sequential drum (Mathews and Moore)
6:00 what the piece sounds like and how it was generated
8:00 control inputs to analog patch - ADSR triggers, pitches, filter parameters
12:00 center-panned voice only speaks on on-eighth-notes
13:00 choice of pitches
14:30 the ADSR envelope generators
16:00 what happens when sustain level changes while ADSR is in D or S phase
18:00 can enter release phase while in A or D
20:30 study patch: signal paths first, then control
23:00 ADSR abstraction
24:00 output is line segments so usually need to apply a nonlinear function
24:30 band-limited sawtooth generator
25:30 resonant filter
26:00 panner
27:00 control panel: tempo in attacks per minute
28:00 ADSR abstraction has a peak-amplitude parameter (unlike analog ones)
30:00 preview of mechanism to build control panel
31:00 six parameters for each ADSR (one for amplitude and one for VCF)
32:00 pitch, pan, and q are per-voice (three each eventually)
32:30 units for ADSR envelopes: times in milliseconds
34:30 "peak" is in whatever units used by what you send the ADSR to
35:30 sustain level is a percentage of peak
36:30 effect of changing duration of DASR triggering pulse
39:30 rearranging the patch to contain three oscillators
42:00 control (message) line objects to allow ramps in ADSR parameters
43:00 using the new parameters
44:00 testing ramping the ADSR release time
45:00 comparison of LFO versus ramps to control parameters
47:00 aliasing if paramter is changing faster than ADSR is triggered
50:00 historical hardware was (sort of) using audio-rate parameter changes
52:00 pitch is fixed for duration of each individual note (not continuous)
54:00 abstraction for the oscillator so we can make 3 copies
56:00 pan controlled inside abstraction
57:00 individualize pan using a control with a per-copy name
58:00 gotcha: don't retype an abstraction if you're editing the interior
59:00 use outlets for output signals and add them outside the abstraction
1:00:00 parameters for filter: center frequency (as pitch) and q
1:02:00 need two filters, one for each output channel
1:05:00 managing triggers for ADSRs (delay equal to note duration)
1:06:00 random choice of which voice to trigger each tick
1:07:00 pitch1, etc, parameters to set pitch
1:07:30 rebuilding control panel
1:09:00 genctl takes an argument to specify default (reset) value
1:10:00 testing the three-voice patch driven by a metronome
1:11:00 imitate detuning of analog oscillators
1:12:00 grab all the parameters and put in a message box
1:14:00 rhythmic detail in the piece: center voice is accented
1:16:00 center-panned voice only appears on on-sixteenths
1:17:00 no hardware sequencer (it was in the computer program)
1:18:00 computer also had live analog inputs

271b-07b-may12.mp4: Meeting 7b, May 12, 2021

0:00 photo of control panel for (I think) GROOVE system
1:30 center frequency, bandwidth and q of a resonant filter
8:30 Moog ladder filter compared to vcf~ object
10:00 affordances of computer-controlled analog versus digital synthesis
12:30 imitating rhythmic pattern in Appalachian Grove
22:00 will skip doing the accents correctly
23:31 control of pitches
26:00 the value object, used to read next-pitch into correct voice
27:00 why you don't need a trigger to control order of pitch versus ADSR
31:30 selecting pitches from a collection
33:00 one way to make a pittch set: 7-element array with a message to fill it
34:30 perhaps better alternative: use a text object to hold the pitch set
38:00 array for pitch probabilities
41:00 bob~ object: ladder filter, alternative to vcf~
53:00 adding reverberation
54:00 automatic control panel generator
55:30 looking at saved patch to learn how to create objects
57:00 windows in Pd can be sent messages by window name
1:00:00 make-ctls sub-patch.  Catching the first in a sequence of messages
1:02:00 counter to set y location of controls in new panel
1:03:00 supplying default arguments to messages using unpack
1:08:00 time stretching (sort of) using long reverberation
1:11:00 short versus lnog sinusoidal burst into infinite reverb
1:16:00 this is probably what was done with bird sounds in Westercamp piece
1:16:30 other ways: phase vocoder (e.g., Wishart); resonant filters (Saariaho)

271b-08a-may19.mp4: Meeting 8a, May 19, 2021

0:00 invited talk: Kerry Hagan (Univ. of Limerick), ...of pulses and times...
4:30 generative music and electronic music genres
6:00 inspired by Nick Collins.  Probabilistic analysis of beat music
7:30 algorithmic versus generative music and electronic music genres
8:30 another inspiration: Mortom Feldman's metric modulations
9:30 layering tempos with different pulses
11:00 playing the piece from the patch (note: recording is only one channel)
18:00 why not use samples
19:00 top-down design of piece
20:00 score is series of messages
21:30 metric modulation subpatch
24:00 metronome objects generating different subdivisions of beat
25:00 non-unifirm probabilities
27:00 10 percent nonuplets, etc.
28:00 random selection of sounds depending on beat
30:00 occasional detour nito triplets (dubstep reference)
33:00 sound generator subpatches
35:30 usnig vline object to make stuttered pulses
37:30 attacks don't exactly repeat so that successive events aren't identical
39:30 FM instrument borrowed from another piece, Morphons and Bions
41:30 chirps, drones, and swoops
43:00 patch can play automatically or be performed live
45:00 automatic meter changes
47:00 Pd programming style
48:30 preparing patches to be played without composer present
50:00 control surfaces
52:00 memoryless processes and longer time durations
54:30 piece can sound different every time although the form is fixed
57:00 comparison with fixed-media pieces
1:00:00 real time is fundamentally different compositionally
1:01:00 multichannel sound and real-time spatialization
1:03:00 no filtering used (but some broad-band sounds and some narrow ones)
1:06:00 using filters in generatove or algorithmic music
1:06:30 serialism and representation of all musical values as numbers
1:08:00 role of accident in stochastic music
1:11:00 narrative and musical form
1:14:30 how strictly should a performance follow the "score" (message sequence)

271b-09a-may26.mp4: Meeting 9a, May 26, 2021

0:00 more on Manoury, Pluton.  Running patch using recorded piano and MIDI
6:30 "section 100" - qlist1.txt and score1.txt
7:30 score follower compares incoming MIDI from piano with score
8:00 example: C-D-E-F-G-F-E-D-C-C-C-C-C-C in score and repeated Cs from keyboard
9:00 jumps to event 19
10:30 concert setup for Pluton.  MIDI interface, PianoBar designed by Buchla
11:00 audio conections
11:30 logical diagram: frequency&pitch shifters, reverb, spatialization
12:30 oscillator bank controlled by FFT analysis of piano; and live sampler
13:30 how MIDI input is used: first, velocity-controlled spatialization
14:30 second use for MIDI input: training a Markov chain
15:30 third use: score following.  Barry Vercoe and Roger Dannenberg
16:30 score-following driven sequencing (qlist)
18:30 don't need to send MIDI back to "play" piano
19:30 score following algorithm.  Possibility of very tight synchrony
21:30 explanation of how the example from 8:00 worked
24:30 finding best possible path connecting score with performance
27:00 each path has a conditional probability (incorrectly called "likelihood")
30:30 most probable path implies where we want the computer to be
32:00 equivalent to Viterbi algorithm for a particular hidden Markov chain
34:00 related term: "dynamic programming"
35:30 limitation: this approach doesn't take advantage of timing of events
36:00 why people don't often use score following today
37:30 polyphonic score following
39:00 only using note onsets as input to score following is a severe limitation
44:00 research problem: score following for Pluton using audio alone
46:00 "notes.txt" file in patch show what labels are where in score
47:00 Event 31 (section IV): FFT-controlled oscillator bank
47:30 section II introduces oscillators and Markov chain and alternates them
48:30 section III Markov alone
50:30 "gumbo" objects that control pitches of oscillators
51:00 oscillator control panel.  Capital and small "o" .  Oto2, Oto4, etc.
56:00 amplitudes of oscillators controled by FFT analysis as in a vocoder
58:00 spectral shift and response speed controls
59:00 why this doesn't sound like a vocoder used in the usual way
1:01:00 usnig the four 12-voice banks as one larger bank (gumbo5 object)
1:02:30 why the "gumbo" object has setparate "set" and "bang" messages
1:03:30 "mode 1" loads pitches into the oscillators from piano keyboard
1:08:00 aliasing effect in FFT analysis if speed set high
1:10:00 setting speed to zero freezes spectrum
1:11:00 cross-fading between spectra
1:12:00 different wavetables
1:14:00 patch to simulate piano (audio and MIDI).  Section III, events 1-6
1:18:00 Pd patch adapted from original Max patch

271b-09b-may26.mp4: Meeting 9b, May 26, 2021

0:00 Markov chain object ("mark" receive name)
1:00 recording MIDI into the Markov chain which controls a sampler
1:30 "trec" message records; "play1" plays back
3:00 Record a chain C-D-E-F-G-C
3:30 Oops, need to clear the chain first
4:00 ambitus control
5:00 transition probabilties in Markov chain taken from MIDI velocity
6:00 time limit between notes to make a transition
6:30 restart parameter in case chain gets stuck
8:00 common pitches between different pitch sets to make transitions
9:30 how rhythm is input from MIDI
11:00 if Markov chain has absorbing states it lasts a random amount of time
13:00 section 2: oscillators first, then Markov chain at event 7
16:00 Markov chains have faded out; oscillators take over
18:00 reemergence of Markov chain
18:30 recording arpeggios into sampler
19:00 ambitus is at zero
20:00 Markov chain disappears a second time
21:30 playing chords into Markov chain (not demonstrated)
23:30 imperfect separation between interaction and score (events 43:1-5)
26:00 three metronomes at different speeds
27:30 event 3 records from piano to sampler bank 2
30:00 pitch shifter ("harmonizer") to make celeste effect
32:30 playing through section V, part E
38:30 granular time stretching in part F
41:00 time stretching played without piano part
42:00 sample played without time stretch
43:00 playback at different speeds. The "rspeed" control
46:00 events 44:1-3 (section E part F)
49:00 ending of piece, 64-to-one time stretch
50:00 spatializer, repeated patterns with variable speed
51:00 tables (arrays) giving x and y coordinates for spatialization
55:00 velocity control of spatialization
57:30 velocity controled crossfades between oscillator banks
1:00:00 velocity control conects piano to electronics
1:05:00 research problem: make a cheap, robust piano MIDI detector
1:06:00 designing pickups for individual piano strings
1:08:00 a more recent algorithm (from Manoury, en Echo): "3F"
1:11:00 three generating pitches generate inharmonic spectra
1:13:00 secret sauce: linear integer combinations of generating frequencies
1:15:00 example: using incoming pitch as one of the three frequencies