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Play · Web Audio · THIRI API

Helix Arpeggiator

A voice-leading arpeggiator with a fat synth, polyphonic harmony, FX and MIDI export.

0 / 50 XP Passport
30 seconds

Pick a progression, press play, drag the helix. Export the MIDI.

Not a loop, a path. Helix voice-leads across an infinite octave lattice; THIRI keeps every note legal, Helix decides which legal note is musical. Works without a key (local chord fallback). Paste your own key for THIRI-verified voicings. Read the report that built this.

Loop up to 16 bars. One chord = 1 bar; append :N for a multi-bar chord (e.g. Cmaj7:2 | Am7 | Dm7 | G7). 4 / 16 bars

THIRI · HELIX Harmonic Arpeggiator · MK I
Current Chord
——
bar — · beat —
API Console chords.thiri.ai
// Console initialized. Waiting for actions...
Oscillator
Waveform
1 Unison
0.0¢ Detune
0.00 Sub
Envelope
0.006s Attack
0.05s Decay
0.50 Sustain
0.09s Release
Filter
18000Hz Cutoff
0.1 Res
Arpeggiator
Density
Motion
Voices
30 Smooth
20 Adv
Harmony

Off = monophonic · 3rd = add interval above · Triad = full chord voicing · Block = dense chord block

FX Rack
Delay
0.28 Mix
250ms Time
0.35 Fdbk
0.60 Ping
4000Hz Tone
Reverb
0.50 Size
0.50 Decay
0.40 Damp
0.00 Shimm
28% 250 0.35 0.60 4000 0.50 0.50 0.40 0.00
0% Swing
0%

Paste a key, edit the progression, hit Load — then Play.

Notes per chord (text view)
THIRI Helix · the engine is deterministic — same seed + parameters reproduce the exact performance. Legality from the THIRI API; the path is computed locally.