What we tested
We generated one 22,050 Hz, 16-bit mono WAV with three C4-to-E4 sections. The first moved directly from C4 to E4. In the second, C4 continued for 0.300 seconds after E4 began. In the third, both notes overlapped for 0.900 seconds. Every tone used the same sine waveform, peak level, attack, and release. No public or named media was used.
| Source overlap | Expected pitches found | MIDI events | Observed behavior |
|---|---|---|---|
| None | C4 and E4 | 2 | One continuous event per note |
| 0.30 seconds | C4 and E4 | 6 | C4 split into 3; E4 split into 3 |
| 0.90 seconds | C4 and E4 | 5 | C4 split into 3; E4 split into 2 |
No overlap produced the cleanest draft
The non-overlapping section produced one C4 event lasting 0.882 seconds and one E4 event lasting 0.895 seconds. Their detected starts were 0.894 seconds apart, closely preserving the intended handoff between the two generated tones.
Overlap preserved pitch but changed note boundaries
With 0.300 seconds of overlap, the converter found both intended pitches but exported three C4 events and three E4 events. The longest C4 segment lasted 0.905 seconds, while E4 was divided into 0.292-, 0.546-, and 0.070-second events.
With 0.900 seconds of overlap, C4 was divided into three events and E4 into two. The two main C4 segments lasted 0.872 and 0.871 seconds; the main E4 segment lasted 0.848 seconds. Across the complete test file, the converter exported 13 events in a 163-byte MIDI file.
Why overlap needs a piano-roll check
When a second pitch enters before the first one ends, the audio changes from a single tone to a two-tone mixture and later back again. A transcription system must decide whether those spectral changes are new onsets, continuations, or endings. In this controlled file, the pitches survived, but the transitions created extra boundaries.
How to clean up overlapping notes
- Compare the transition with the source. Check where the new pitch begins and whether the earlier note should continue underneath it.
- Merge same-pitch fragments carefully. Join adjacent fragments only when the source supports one sustained note.
- Restore the intended overlap. Extend or trim note ends in the piano roll instead of assuming every detected boundary was performed.
- Use a cleaner stem when possible. Other instruments, room sound, and effects can add more competing transitions.
Limits of this result
The test used equal-level C4 and E4 sine tones with the converter's default controls. It did not test every interval, register, instrument, articulation, chord density, or overlap length. It shows one reproducible behavior and does not assign an accuracy percentage.
For notes that begin at the same time, see the controlled chord test. For notes only a semitone apart, see the close-note test.