Chord Finder from Audio - Free, Unlimited, No Signup | EarChord

What

EarChord is a browser-based audio analysis tool that automatically extracts chord progressions, musical keys, and tempos directly from user-provided audio files. Built for musicians, transcribers, and learners, it eliminates the usage limits and subscription barriers common in chord transcription software by processing files client-side. The product is positioned as a free, privacy-preserving, and zero-setup alternative to cloud-hosted chord recognition platforms.

Features

• Client-Side Signal Processing: Decodes and analyzes audio within browser Web Workers using chromagram spectral mapping, ensuring complete file privacy with zero server uploads.
• Interactive Chord Timeline: Generates a synchronized timeline of identified major and minor triads, enabling users to click specific chords to jump playback and verify them by ear.
• Key and Tempo Detection: Computes track key via Krumhansl-Schmuckler profiles alongside beat-per-minute estimation, providing structural song data without manual measurement.
• Roman Numeral Conversion: Formats chord sequences into relative Roman numerals based on the detected key, simplifying harmonic analysis and song transposition.
• Text and File Export: Allows users to copy chord sequences to the clipboard or export the timeline as a standard .txt file for use in notation or chord sheets.

Helpful Tips

• Account for Harmonic Constraints: The detection algorithm is intentionally limited to 24 major and minor triads, meaning extended harmonies like 7th chords, inversions, and suspensions are mapped to their closest triad equivalents.
• Assess Audio Material: Recognition performs best on clear recordings with distinct harmonic instruments and can degrade on heavily compressed tracks, complex mixes, or distorted power chords lacking third intervals.
• Manage Local Device Memory: Because decoding occurs inside the local browser session rather than a remote server, performance on extremely large audio files depends entirely on host device RAM and processing power.

OpenClaw Skills

The source documentation does not list any native integrations or programmatic APIs for the OpenClaw ecosystem. As a hypothetical use case, an OpenClaw automation agent could ingest exported .txt chord timelines and key data from EarChord to automatically assemble lead sheets, suggest arrangement alternatives, or index music libraries. This type of signal-to-agent workflow could streamline basic music transcription and curriculum preparation for educators and commercial arrangers.