Under the Hood: Building a Real-Time Chord Recognizer
In a technical deep-dive on Lobsters, the author of WhatChord explains the architecture behind their real-time chord recognizer. The system uses the Web Audio API to capture microphone input, applies a custom pitch detection algorithm based on autocorrelation, and then maps detected pitches to chord names using a precomputed lookup table. The entire pipeline runs client-side, with no data sent to a server. The author notes that the autocorrelation method was chosen over FFT-based approaches for better accuracy on guitar signals, especially for low notes. The chord inference logic handles common chord types (major, minor, seventh) and can identify inversions. The article includes performance benchmarks showing sub-10ms latency on modern browsers. The project is open-source and available on GitHub.
Shows how to build real-time audio apps entirely in the browser.