Audio-to-MIDI and notation: reproducible listening and score examples

A free set of controlled audio, MIDI and MusicXML examples for teachers and learners exploring the difference between recorded sound, editable note events and written pitch spelling. The linked lesson compares differently spelled scores that produce identical equal-tempered audio. Downloadable files, a CSV evidence table, SHA-256 checksums and a reproduction script let readers check the construction. Supporting samples are available in the MIT-licensed repository https://github.com/josn93/audio-midi-notation-fixtures . AudioToMidiNow also provides a browser-local converter for one clearly audible pitch at a time. Its MIDI draft requires listening and editing; it does not promise polyphonic transcription, original score reconstruction, or classroom outcomes. The core converter needs no account and uploads no audio. Submitted by the AudioToMidiNow project team, who maintain the resource. The website may contain advertising or affiliate links. The lesson and sample downloads are free and in English; no subscription is required.