What we tested
We generated one 22,050 Hz, 16-bit mono WAV containing three two-note sections: C4 with C-sharp 4, C4 with E4, and C4 with C5. Each pair lasted 1.400 seconds and was separated by 0.500 seconds of silence. Every tone used the same sine waveform, peak level, timing, attack, and release. No public or named media was used.
| Interval | Generated notes | Expected notes found | MIDI behavior |
|---|---|---|---|
| Semitone | C4 + C-sharp 4 | 1 of 2 | C4 missed; C-sharp 4 split into 4 events |
| Major third | C4 + E4 | 2 of 2 | Both main notes plus 2 short tails |
| Octave | C4 + C5 | 2 of 2 | C5 continuous; C4 split into 4 events |
The semitone collapsed to one pitch
The semitone section produced four C-sharp 4 events and no C4 event. Its longest C-sharp 4 segment lasted 1.092 seconds. The file therefore did not preserve both intended chord tones even though both source oscillators had equal peak amplitude.
Wider pairs kept both intended notes
The major-third section retained C4 and E4 with main durations of 1.347 and 1.358 seconds. The octave section retained C4 and C5; C5 lasted 1.358 seconds, while C4 was divided into four events. Across the complete file, the converter exported 13 events in a 161-byte MIDI file.
This comparison changes interval width and frequency while keeping the source construction fixed. It shows what happened to these three pairs, but it does not prove that wider intervals will always work or that every semitone will fail.
Why adjacent pitches are a harder review case
Audio contains overlapping frequency patterns rather than labeled MIDI keys. When two fundamentals are close, their combined waveform and harmonics can make separate note boundaries less clear to a transcription model. Instrument tone, tuning, phase, room sound, and other parts in a mix can all change the result.
How to review close harmony
- Check every intended chord tone. A plausible top note does not prove the lower adjacent note survived.
- Look for split events. Merge same-pitch fragments only after comparing them with the source.
- Try a cleaner stem. Isolating the relevant instrument can remove competing energy without changing the musical interval.
- Add missing notes manually. MIDI is an editable draft, so restore a known inner voice in the piano roll when needed.
Limits of this result
The test used steady equal-level sine tones and the converter's default controls. It did not test every register, interval, instrument, inversion, tuning, or chord density. It records one reproducible boundary from the current converter without assigning an accuracy percentage.
For ordinary triads, see the controlled chord test. For one note placed between equal-tempered pitches, see the detuned-note test.