Writing on chords, harmony, and how WhatChord works.
Guides for musicians on naming, writing, and identifying chords, plus technical deep-dives and research notes behind the analysis engine.
For Musicians
Why Chord Naming Is Harder Than It Looks
The inversions, extensions, altered tones, and enharmonic ambiguities behind real chord recognition, and how WhatChord handles them.
Read the article →Chord Naming Guide
How to move from notes to a chord name using default interval qualities, degree formulas, spelling, and candidate roots.
Read the guide →Chord Symbol Guide
How WhatChord formats chord symbols: extensions, added tones, alterations, parentheses, and slash bass, with the reasoning behind each choice.
Read the guide →Technical Deep-Dives
Building a Real-Time Chord Recognizer
The bitmasks, chord-quality templates, explanation costs and ranking heuristics, and LRU cache behind real-time chord recognition.
Read the article →Optimizing an Algorithm That’s Quadratic by Design
Why the chord comparator is non-transitive, why that forces an O(n²) Copeland linearization, and how we cut its cost by an order of magnitude without changing what a musician sees.
Read the article →Benchmarking on Hardware You Don’t Control
Reference-normalized time, deterministic operation counters, and a calibrated noise model: how we measured engine changes reproducibly on shared CI runners.
Read the article →What We Learned From 1 Million Chord Annotations
How a large public chord corpus helped validate WhatChord’s chord vocabulary and guide future recognition priorities.
Read the article →Streaming Key Estimation Research
The research project behind automatic key detection: a frozen evaluation protocol, versioned fixtures, external baselines, dated experiment logs, and held-out results.
Read the research notes →