Gene a i e Techniques in “The Thi d Man,” o
F e less Elec ic Gui a and Elec onics
Adam James Wilson∗
New Yo k Ci y College o Technology, Ci y Uni e si y o New Yo k
[email p o ec ed]
Abs ac
“The Thi d Man” is he la es in a se ies o pieces, spanning i een yea s o i e a ion,
o solo e less gui a and “au oma ic imp o isa ion” so wa e. P io wo ks in he
se ies ha e been pe o med h oughou he Uni ed S a es, many o hem a he New
Yo k Ci y Elec oacous ic Imp o isa ion Summi be ween 2016 and 2024. The
au ho se es as he p incipal pe o me /compose and p og amme o his and
p io wo ks, which has enabled he p og essi e e inemen o gene a i e echniques
o suppo e y pe sonal composi ional aes he ics and pe o mance p ac ices. Se -
ing aside he s ylis ic idiosync asies hey se e, de ails o he ela i ely simple
gene a i e echniques used in “The Thi d Man” a e he main ocus o his a icle.
1 O e iew
“The Thi d Man
1
” p esen s, hy hmically and imb ally, as a jazz usion qua e (d ums, bass, ha mony
and lead gui a ). Howe e , aside om being mos ly algo i hmically gene a ed and o ches a ed
wi h i ual ins umen s, i de ia es om he usion adi ion h ough (1) use o ha monies buil on
a mic o onal scale and (2) sub le deploymen o passages ha human ins umen alis s would ind
impossible. D ums a e p e-gene a ed om a sho ke nel o composed music, p o iding a sca olding
o o mal s uc u e, while ha monies a e gene a ed in eal ime and de elop acco ding o a ew
ule-based sys ems and a simple p obabili y model applied o a ac o o acle ep esen a ion o music
p oduced by he imp o ising gui a is . Pi ches and no e du a ions om he li e gui a a e acked in
eal ime and quan ized o a pi ch-du a ion c oss-alphabe be o e being ed o he ac o o acle. The
pi ch o he li e gui a is used o adjus he e e ence equency o he scale om which ha monies
a e de i ed.
2 D ums
P e-gene a ed d ums a e he only immu able elemen s in “The Thi d Man.” The pe cussion ins u-
men s dic a e he o e a ching o mal s uc u e o he piece and con ain cues o pa ame e iza ion
o ha mony ins umen s. So wa e o gene a ing he d ums,
D umGen
, was w i en in he Ruby
p og amming language. Al hough i is mos o en used o web de elopmen , Ruby has an elegan ,
sel -documen ing syn ax, making i ideal o apid p o o yping in many con ex s.
The design o he
D umGen
is simple. The use s a s by de ining a “ki ,” which maps human- eadable
and seman ically meaning ul symbols o MIDI key and con olle numbe s a ge ing a pa icula
syn hesize o sample . Ki s a e e e enced inside he
Pa e n
class, ins ances o which encapsula e
∗h ps://adamjameswilson.in o
1
The i le o he piece e e s o a mys e ious p esence, such as ha e e enced in The Was e Land (Elio ,
2001), mani es ing i sel in soundscapes ha appea —despi e a ising om conc e e in e ac ions be ween
he imp o ising gui a is , compose /p og amme , and so wa e— o ma e ialize au onomously. C edi o he
i le goes o E ic Lyon (2017), who o iginally made he analogy be ween The Was e Land and a simila
piece, “Eigh een Eigh een,” pe o med a he 2016 New Yo k Ci y Elec oacous ic Imp o isa ion Summi
(h ps://eis.nyc/#--p og am-2016).
P oceedings o he 6 h Con e ence on AI Music C ea i i y (AIMC 2025),
B ussels, Belgium, Sep embe 10 h-12 h
sequen ial musical e en s. E en s a e exp essed as a wo-dimensional a ay o “s ikes:” ows hold
e en s, and columns hold in o ma ion de ining a single e en , including ins umen name, a icula ion
ype, du a ion, ampli ude, and pi ch con olle alue. The
Ri
class combines ins ances o
Pa e n
“ e ically.” Ins ances o
Ri
can also be s ung oge he sequen ially. Finally, a
build_pa e n
unc ion is used o e-hash pa e ns in o new o ms. I allows he use o choose he du a ion o he
ou pu pa e n, he sou ce pa e ns o d aw om, he op ion o emo e all es s, he minimum and
maximum leng hs o andom chunks o pa e ns o conca ena e, he p obabili y ha selec ed chunks
will appea in e e se o de , a lis o ins umen s o hin, a global du a ion coe icien , and a lis o
ins umen s o “buzzsaw,” o di ide in o apid a acks ha pi ch-shi along a cu e.
5:4
+
1
24
high ha
4
4
1
12
4
4
= 172
9
+
o
1
6
sna e
1
6
1
10
15:16
1
4
kick
ide
o
1
4
high ha 5:4
1
5
sna e
o
3:2
1
6
om 2
5:4
1
20
ide
1
20
sna e
skins 1
ha and
ide 1
3:2
3:2
3:2
15:16
+
1
4
high ha
4
4
1
4
kick
4
4
= 172
+
1
12
0
1
60
om 2
-1
-2
-3
-4
o
1
6
-5
-6
-7
ha and
ide 2
-8
-9
0
1
24
om 1
skins 2
3:2
75:64
+
1
12
1
24
1
6
ide
1
24
0
1
200
om 2
-3
-6
-9
3:2
3:2
0
1
120
sna e
+2
0
1
40
o
1
3
high ha
+2
+4
+6
Figu e 1: P e-composed ( op measu e) and gene a ed pe cussion exce p s. Ra ios indica e ac ions
o a whole no e. In ege s indica e pi ch de ia ion. Each ca ego y o no e ma king (dynamics, a ios,
pi ch de ia ions, ins umen labels, a icula ions) pe sis s un il he nex ma king o he same ype.
The i s ba in Figu e 1 shows music composed wi h
D umGen
. No e he in e pene a ion o pulse
di isions on bea s h ee and ou o “skins 1.” These discon inui ies gi e he d ums a human quali y,
while he “buzzsaw” echnique shown in he ollowing ba p o ides an ex a-human quali y.
3 Bass
Fo each bass a icula ion ollowing a gui a no e onse , he bass chooses be ween he mos consonan
in e als ha can be o med wi h he cu en gui a no e using he scale shown in Figu e 2: 0.0,
2
701.96, 386.31, 203.91 (cen s) o 1/1, 3/2, 5/4, 9/8 ( equency a ios). Ra ios wi h smalle p ime
ac o s in bo h he nume a o and denomina o a e pe cei ed as mo e consonan (Pa ch, 1974), hence
he “5-limi " obse ed he e.
S=
[0.0, 104.96, 203.91, 297.51, 386.31, 470.78, 551.32,
628.27, 701.96, 772.63, 840.53, 905.87, 968.83,
1029.58, 1088.27, 1145.04]
Figu e 2: Scale used as he basis o all gene a ed ha monic con en in he “The Thi d Man” exp essed
in cen s.
S
is made up o he i s six een odd ha monics abo e a e e ence equency. I has ela i ely
ew consonan in e als, wi h only 0.0, 203.91, 386.31, and 701.96 (1/1, 9/8, 5/4, 3/2) alling a o
below he 5-limi .
A e he ini ial choice, and be ween onse s in he li e gui a , he bass can choose om he union o
he abo e ou pi ch-classes and he wo pi ch-classes neighbo ing he las chosen alue (e.g., 104.96
and 1145.04 i he las alue chosen was 0.0).
s a ge gp bp =gp +x∈RC
gui a
onse ?
bp =gp +x∈R(C∪ {S[index(S, bp)±1] mod 16})
yes
no
Figu e 3: P ocess o choosing bass pi ch-classes:
gp
is he gui a pi ch-class;
bp
is he bass pi ch-
class;
C={0.0,701.96,386.31,203.91}
, he se o pi ch-classes ha o m he mos consonan
in e als wi h
gp
;
S
is he comple e lis o a ailable pi ch-classes shown in Figu e 2. All alues a e
exp essed in cen s.
4 Ha mony gui a
Vi ual gui a accompanimen is p oduced by a Max ex e nal called
ealgui a
, which ini ially
uses a a ian o he Fische -Ya es shu le o assign pi ch-classes om
S
o s ings. A 4:10, a much
mo e in e es ing algo i hm, le e aging a ac o o acle ini e s a e au oma on, akes con ol o he
accompanimen .
012345
2
4
4 4
2
2 4
Figu e 4: Fac o o acle o he s ing “24424."
4.1 Wha is a ac o o acle?
A ac o o acle is a di ec ed acyclic wo d g aph capable o p oducing all subs ings o a wo d.
Following all sequences o ansi ions (solid a ows) s a ing om s a e 0 in Figu e 4 yields all
3
subs ings o he wo d “24424.” Do ed a ows ep esen su ix links, which a e a i ac s o he ac o
o acle cons uc ion algo i hm. Each su ix link poin s o he end o a subs ing ha sha es he longes
su ix wi h he subs ing ending i s o igin s a e. Each subs ing
s1
ending wi h a skip-s a e ansi ion
poin s o he end o a subs ing s2sha ing a common su ix wi h s1.
One side e ec o he ac o o acle cons uc ion algo i hm is he occasional disco e y o subs ings
ha don’ exis in he inpu wo d. Despi e his sho coming, ac o o acles a e mo e memo y e icien
han su ix ees, and, unlike su ix ees, ac o o acles can be buil in eal ime. This makes he ac o
o acle pa icula ly use ul o handling musical da a ob ained om a li e imp o isa ion, a si ua ion in
which he comple e s ing canno be known in ad ance.
An exhaus i e in oduc ion o ac o o acles is gi en in Allauzen e al. (1999).
Figu e 5: Max pa ch showing he in e ac ion be ween quan ize,xalpha, and o ex e nals.
4.2 How is ac o o acle used in “The Thi d Man?”
“The Thi d Man” uses a modi ied e sion o he
ac o O acle2
ex e nal (
o
), w i en o he Max
and Pu e Da a p og amming en i onmen s (Wilson, 2016).
The e a e wo pa allel p ocesses in
o
: cons uc ion o he au oma on and a e sal o he au oma on
o gene a e music. P io o cons uc ion, musical pa ame e s o in e es a e combined in o unique
okens—in his case, a c oss-alphabe o six een pi ch-classes
S
and a ange o wen y du a ions. Fo
each incoming gui a no e, he du a ion and undamen al equency a e de ec ed, and each alue is
quan ized o he closes membe in i s associa ed alphabe and hen encoded wi h a unique in ege
m
,
whe e 0<=m < 320.
Quan iza ion and encoding/decoding o c oss-alphabe alues a e handled by Max ex e nals
quan ize
and
xalpha
, espec i ely. Fac o o acle a e sal, ac ua ed wi h a “bang” in he le
inle o
o
, ollows a simple scheme: a alue
P
is assigned by he use , which go e ns he p obabili y
o aking a o wa d link as opposed o a su ix link. Using su ix links u ns he ac o o acle in o a
cyclic wo d g aph, so ha i can be used con inuously o gene a ion. Following mo e su ix links
means mo e de ia ion om “idioma ic” sequences.
As he li e gui a is lis ens o he ou pu o
o
, a eedback loop eme ges: less idioma ic ecombina ions
o in e es can be ein o ced in he model h ough epe i ion by he gui a is , while unin e es ing
ecombina ions can simply be igno ed.
2h ps://gi hub.com/ajwnycc / ac o O acle-Max
h ps://gi hub.com/ajwnycc / ac o O acle-Pd
4
Re e ences
Allauzen, C., C ochemo e, M., and Ra ino , M. (1999). Fac o o acle: A new s uc u e o pa e n
ma ching. Lec u e No es in Compu e Science, 1725:295–310.
Elio , T.S. (2001). The Was e Land, page 17. W.W. No on & Company, Inc., New Yo k, New Yo k.
Ed. Michael No h.
Lyon, E. (2016/2017). The i s NYC Elec oacous ic Imp o isa ion Summi , New Yo k Ci y College
o Technology. A ay, he Jou nal o he In e na ional Compu e Music Associa ion, page 55.
Pa ch, H. (1974). Genesis o a Music, page 86. Da Capo P ess, New Yo k, New Yo k.
Wilson, A. (2016). ac o O acle: an ex ensible Max ex e nal o in es iga ing applica ions o he
ac o o acle au oma on in eal- ime music imp o isa ion. In P oceedings o he 4 h In e na ional
Wo kshop on Musical Me ac ea ion, Pa is, F ance.
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