A beatmaker that listens to its own songs.

How Golden Pulse was made

One command. It generated four deep house songs, then bred them for four generations of eight children each. Every child was auditioned on its build-up and first drop, and the four the critic liked best became the next parents. --no-library keeps Apple Loops and your own samples out; the sample packs still play.

Command

claudius evolve --genre deep_house --seed 5 --generations 4 --no-library

What it printed (… marks lines left out)

evolving deep_house (4 start, 4 generations x 8 children, 32-bar previews, with ears)
  g0-0  86.1  Hollow Harbor
  g0-1  80.0  Paper Haze
  g0-2  85.0  Glass Garden
  g0-3  85.9  Golden Pulse
+ g1-0  87.0  from g0-3: shaker: synth voice parameter 8 -> 0.079; mix: perc +2.4 dB (now +2.4)
+ g1-1  86.7  from g0-2: form: intro gets fills; drums: played on the tr808 kit
+ g1-2  86.3  from g0-3: harmony A: chord 2: IV7 -> IV (plain triad)
  g1-3  84.9  from g0-2: harmony A: swapped chords 3 and 4; mix: pad sidechain depth 0.49
  g1-4  85.3  from g0-0: drums: new clap pattern; mix: hat +1.9 dB (now +1.9)
  g1-5  79.2  from g0-0: crossover: drums and form of one parent, harmony and parts of the other; mix: pad +1.6 dB (now +1.6)
+ g1-6  86.7  from g0-3: swing 0.55 -> 0.53; chords (keys): drive 0.4 dB
+ g1-7  86.1  from g0-0: crossover: drums of one parent, everything else of the other; pad (warm_pad): release 2.59 s; form: drop now 24 bars
generation 1: best 87.0
…
generation 4: best 90.1
searched 36 candidates in 76 s; rendering the best 3 in full
#1 g4-1 (Golden Pulse): preview 90.1, full song 89.7
    swing 0.55 -> 0.53
    chords (keys): drive 0.4 dB
    pad: rewrote the part
    drums: played on the muldjord kit
    crossover: drums of one parent, everything else of the other
    kick: synth voice parameter 3 -> 0.447
    form: break now 24 bars
    crossover: drums and form of one parent, harmony and parts of the other
    mix: hat -3.0 dB (now -3.0)
Golden Pulse — deep_house at 120 BPM in A dorian, 112 bars (3:44)
  progression A: i9 IV7
  progression B: i IV7
  form: intro 16 | groove 16 | break 24 | build 8 | drop 32 | outro 16
  tracks: kick (synth kick), clap (sampled cp (tr808:cp)), hat (sampled hh (tr808:hh)), shaker (synth shaker), perc (sampled rim (tr808:rim)), bass (synth patch 'sub_bass'), chords (synth patch 'keys'), pad (sampled string_ensemble (vsco2:strings)), lead (sampled rhodes (jrhodes:rhodes)), crash (synth crash), riser (synth riser)
  master: -11.0 LUFS, true peak -1.0 dBTP (pre-master -10.3 LUFS)
  ears: 'house music' z +3.8 (closest confusion 'techno music' +3.1); production z +1.5 vs 'a low quality recording with hiss' +1.1; p_real 0.71
        sounds like: house music, tech house music, drum and bass music, techno music
  verdict: 90/100 (arc 0.92, genre 0.93, mix 0.95, production 0.59, theory 1.00). Fix first: dull 4-8 kHz: hats, claps and snare lack bite (presence -28.6 dB, healthy from -26); production reads close to 'a low quality recording with hiss' (z +1.1) vs professionally mixed (z +1.5)
  wrote out/evolve-deep_house-5/1-g4-1-golden-pulse/song.mp3

The winner, printed as a script

// Golden Pulse — deep_house (seed 8)
// song("deep_house", 8);   // uncomment to start over from the generator
title("Golden Pulse"); tempo(120); key("A dorian"); swing(0.53493524);
humanize(0.35);
prog("A", "i9 IV7");
prog("B", "i IV7");

// drums: X accent, x hit, o ghost, . rest, | bar line; 16 steps per bar unless a number follows
drum("kick", "main", "X...X...X...X...");
drum("kick", "sparse", "X...X...X...X...");
drum("clap", "main", "....X.......X...");
drum("hat", "main", "x.xxx.x..xxxx.x.|x.xxx.x..xxxx.x.|x.xxx.x..xxxx.x.|..xx.xx...xxxxxx");
drum("hat", "sparse", "..x...x...x...xx");
drum("shaker", "main", "o.o.o.ooo.ooo.o.");
drum("perc", "main", "x.x..x.x.x..x.x.");
drum("perc", "sparse", "..x.....x....x..");

// parts written by the theory engine: change the style, preset, register, density or seed
part("bass", #{ style: "syncopated", preset: "sub_bass", register: [33, 50], density: 0.4658955, seed: 7593466037959292827 });
part("chords", #{ style: "stabs", preset: "keys", register: [53, 74], density: 0.43242535, seed: -1845194844081732826 });
part("pad", #{ style: "sustain", preset: "vsco2:strings", register: [50, 76], density: 0.403872, seed: 5506831138054929778 });
part("lead", #{ style: "motif", preset: "jrhodes:rhodes", register: [62, 84], density: 0.34817874, seed: -2367553514172308588 });

form([
  sec("intro", 16, "kick hat shaker perc top").filter_in(),
  sec("groove", 16, "kick clap hat shaker perc bass chords top"),
  sec("break", 24, "pad chords lead shaker"),
  sec("build", 8, "clap hat shaker chords lead pad").energy(0.55).prog("B"),
  sec("drop", 32, "kick clap hat shaker perc bass chords lead pad top").energy(0.9),
  sec("outro", 16, "kick hat shaker perc bass"),
]);

mix("clap", #{ reverb: 0.3 });
mix("hat", #{ level: -2.9886246, pan: 0.18 });
mix("shaker", #{ pan: -0.3 });
mix("perc", #{ level: 2.3582892, pan: 0.4, reverb: 0.1, delay: 0.2 });
mix("bass", #{ duck: 0.45 });
mix("chords", #{ reverb: 0.3, delay: 0.1, duck: 0.35 });
mix("pad", #{ reverb: 0.4, duck: 0.4 });
mix("lead", #{ reverb: 0.35, delay: 0.25, duck: 0.15 });
mix("fx", #{ level: -3, reverb: 0.3 });