Harmonicon adds real-time pitch trainer for harmonica bending

Tomaz Canabrava has detailed a new bending trainer screen in Harmonicon, an open-source music practice application built with Rust and the Bevy game engine. The trainer uses FFT-based pitch detection to give harmonica players live visual feedback on bend accuracy, replacing the guesswork beginners face when learning to alter embouchure and throat shape. It supports structured drills, progress tracking across all harmonica techniques, and customizable tolerance settings.

How the bending trainer works

• Built in Rust with the Bevy game engine; source code available on GitHub
• Uses FFT-based pitch detection (configurable detector, default "C harp · FFT")
• Target card shows real-time cents deviation, stability, and hold duration with a trailing dot visualization of pitch history
• "Check natural note" option calibrates to the actual reed pitch of the user's physical harmonica rather than textbook values
• Six practice modes: Free exploration, Find and hold, Bend and release, Repeated bends, Bend ladder, Overbend response
• Drill mode with adaptive target selection based on practice history and proficiency; progress persists across sessions
• Color-blind accessible progress map using value bars rather than red/green discrimination

Why it matters

The trainer demonstrates how open-source audio tools with low-latency pitch analysis can replace proprietary hardware trainers for instrument technique. Its Rust/Bevy stack may interest developers building similar real-time audio feedback applications.