Research note 01 · Difficulty estimation
Rating the difficulty of piano music
A white-box, multidimensional scale calibrated against repertoire, physical constraints, and a practical human-performance frontier.
Read note 01Piano practice instrument · Windows
KeyfireHelicon
Measure each Take. Repeat difficult passages. See the music take form.
0.1.0 development
Windows x64
Public release gated
Practice with precision
The current passage owns the screen.
Helicon keeps the instrument quiet and the music legible. Configure a passage, play it, review the evidence, and go again.
- 01Practice, Perform, Listen, and wait-for-me timing
- 02Named bookmarks, A/B loops, speed control, and metronome
- 03Continuous note and pedal scoring with durable Take history
- 04Roll, synchronized notation, and 88-key visualization
Music, measured
Difficulty is not one thing.
Elevation describes the demands of an exact arrangement through nine inspectable factors—not an opaque grade or a judgment about the player.
Speed, density, reach, travel, rhythm, coordination, endurance, structural pattern, and landing combine into a versioned, deterministic analysis. The scale centers the frontier of human performance at 100 and remains unbounded above it.
Read the Elevation research note73 Elevation
Guidance with provenance
A suggestion should know when to be silent.
Helicon preserves human fingering, marks generated suggestions separately, and withholds ambiguous answers instead of forcing a number onto every note.
- 01Recorded fingerings and manual edits remain authoritative
- 02Dynamic programming searches complete, physically constrained paths
- 03A confidence threshold controls coverage before practice begins
Generated path · Right hand
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Coverage 78.9%Balanced confidence0 violations
Research notes
The difficult parts are worth documenting.
The research archive records the problem, the evidence, the failed approaches, and the boundary between what Helicon knows and what it only proposes.
Research note 02 · Constrained search
Generating playable fingerings
Why sequence-level search, physical constraints, provenance, confidence, and abstention matter more than filling every note.
Read note 02Built in the open
Inspect the instrument.
Helicon is written in C# and .NET. Its algorithms, benchmarks, architecture notes, and Windows packaging process live with the source.