Music Theory Performance Analysis

8/13/2019 Music Theory Performance Analysis

http://slidepdf.com/reader/full/music-theory-performance-analysis 1/43

Music Theory andPerformance Analysis with

Sebastian and CzernJames Tauber @jtauber





Sebastian



Mathematical:Symbolic more than

Numerical



repetitive

hierarchicalsequent ial + parallel

factorableunderspecified

Modeling Music



Point of Departure

[ {PITCH: 3, OCTAVE: 5, DURATION: 16},

{PITCH: 2, OCTAVE: 4, DURATION: 8}

]

{

{OFFSET: 0, PITCH: 37, DURATION: 16},

{OFFSET: 16, PITCH: 21, DURATION: 8}

}

or



Three Blind Mice

mice =

(seq1 * 2) + (seq2 + seq2a) + (seq2 + seq2b) + ((seq3 + seq3a) * 2) +

(seq3 + seq3b) + seq1



Three Types of Sequence

HSeq — Horizontal / Sequent ialVSeq — Vertical / Parallel

OSeq — Offset-based



HSeqeach element follows the previous

concatenate(next_seq)

repeat(count)

__add__

__mul__

A = B * 2 + C





OSeq

factory function that returns a class

using the given offset attribute andduration attribute

def OSeq(offset_attr,

duration_attr)has operators of both HSeq and VSeq



All Sequences

__init__(*elements)

__getitem__ & __len__

__eq__ & __ne__

transform(func)

__or__

A = B | transpose(5) | reverse()







Pitch

note names

two numbers or one?

MIDI pitch

Hewlett’s base-40 system

my own system

just have transforms for conversion





Lilypond

from sebastian.lilypond.interp import parse seq1 = parse("e4. d c r")seq2 = parse("g4. f4 f8 e4.")seq2a = parse("r4.")seq2b = parse("r4 g8")

seq3 = parse("c'4 c'8 b a b c'4 g8 g4")seq3a = parse("g8")seq3b = parse("f8")



Lilypond

seq1 = parse("e4. d c r")

[{'midi_pitch': 52, 'offset_64': 0,

'duration_64': 24}, {'midi_pitch': 50,

'offset_64': 24, 'duration_64': 24},

{'midi_pitch': 48, 'offset_64': 48,'duration_64': 24}, {'offset_64': 96}]



MIDI

library for parsing and generating MIDI files

from sebastian.midi import write_midi write_midi. write("mice.mid", [ mice])



Alberti

common classical figuration of a triad

a function from a triad to a sequence ofnotes

great example of factorization andunderspecification



Alberti

def alberti(triad):

return HSeq([ triad[0], triad[2], triad[1], triad[2]

])



Alberti

root_triad = VSeq( Point(degree=1), Point(degree=3), Point(degree=5))

quaver = Point({DURATION_64: 8}) alberti_seq =

OSequence( alberti(root_triad) * 16 | add(quaver) )



Alberti

C_major = Key("C", major_scale)

seq = alberti_seq | degree_in_key_with_octave(C_major, 5) | midi_pitch() write_midi. write("alberti.mid", [seq])



What’s Next?

a lot more examples

better use of MIDI input control over instruments in MIDIoutput

nesting of sequences (for hierarchy) the notion of a “head” point



Sebastian



github.com/

jtauber/

sebastian



Czerny



What’s the Difference

between the “Score” and the “Performance”



Positive vs Negative

Differences

study expression the performer isadding

what errors were made? what

inconsistencies or unevenness?





Representing the Score

just another sequence of eventsbut this time desired events

and with less information



C major scale ascending thendescending over oneoctave

represent as sequenceof note + duration

60 8 62 4 64 4 65 4

67 4 69 4 71 4 72 8 71 4

69 4 67 4 65 4 64 4 62 4 60 8



MIDI Performance 4d54 6864 0000 0006 0000 0001 01e0 4d54 726b 0000 00cd 00ff 0308 2364 6566 6175 6c74 00ff 0413 5374 6569 6e77 6179 2050 6961 6e6f 2048 616c 6c00 ff58 0404 0218 0800 ff59 0200 0000 ff54 0521 0000 0000

00ff 5103 07a1 2089 6d90 3c4f 832b 903e 3a2c 903c 0081 3290 3e00 0390 403f 8137 9040 001f 9041 4181 3e90 4100 0790 4344 812d 9043 002a 9045 4d81 2090 4500 2690 473b 814b 9047 0018 9048 5583 2690 4800

0b90 473b 8148 9047 0006 9045 3b81 5990 433d 0490 4500 8132 9043 0022 9041 3981 2c90 4100 2090 4038 810e 9040 0035 903e 3081 1490 3e00 4190 3c42 831c 903c 0000 ff2f 00



Performance Eventsoffset in “ticks”

MIDI pitch

velocity

0 velocity indicatesnote off

1261 60 79 1688 62 58 1732 60 0 1910 62 0 1913 64 63 2096 64 0 2127 65 65 2317 65 0 2324 67 68 2497 67 0 2539 69 77

2699 69 0 2737 71 59 2940 71 0 2964 72 85 3386 72 0 ...



Performance Eventsconvert fromnote start + note end

to just

start + duration

1261 60 79 471 1688 62 58 222 1913 64 63 183 2127 65 65 190 2324 67 68 173 2539 69 77 160 2737 71 59 203 2964 72 85 422 3397 71 59 200

3603 69 59 221 3820 67 61 182 4036 65 57 172 4240 64 56 142 4435 62 48 148

4648 60 66 412



We Want to Diff 1261 60 79 471 1688 62 58 222 1913 64 63 183 2127 65 65 190 2324 67 68 173 2539 69 77 160 2737 71 59 203 2964 72 85 422 3397 71 59 200

3603 69 59 221 3820 67 61 182 4036 65 57 172 4240 64 56 142 4435 62 48 148

4648 60 66 412

60 8 62 4 64 4 65 4 67 4 69 4 71 4 72 8 71 4

69 4 67 4 65 4 64 4 62 4

60 8

vs



Want to Diff

to diff, you must first align

alignment is a dynamic programmingproblem generally relying on notion ofscoring the relati ve cost of adding,deletion or changing items

the “change” score can be very domainspecific

Needleman-Wunsch algorithm



“Change” Score

just consider note value: +1 if same, 0 ifdifferent

or: +1 if same, +0.5 if a tone or semi- tone apart, 0 if more

duration? wrong octave?



Result ((60, 8), (1261, 60, 79, 471))((62, 4), (1688, 62, 58, 222))((64, 4), (1913, 64, 63, 183))((65, 4), (2127, 65, 65, 190))((67, 4), (2324, 67, 68, 173))

((69, 4), (2539, 69, 77, 160))((71, 4), (2737, 71, 59, 203))((72, 8), (2964, 72, 85, 422))((71, 4), (3397, 71, 59, 200))((69, 4), (3603, 69, 59, 221))

((67, 4), (3820, 67, 61, 182))((65, 4), (4036, 65, 57, 172))((64, 4), (4240, 64, 56, 142))((62, 4), (4435, 62, 48, 148))((60, 4), (4648, 60, 66, 412))



Visualizing Mistakes



Czerny



github.com/jtauber/

czerny



Music Theory andPerformance Analysis with

Sebastian and CzernJames Tauber @jtauber

Documents

Music Theory Performance Analysis