DIAGNOSE BEFORE EDITING

How to Fix MIDI Timing Issues

First decide whether the notes are stored at the wrong positions or only sound late during playback. If the MIDI blocks are misplaced, check tempo and quantize settings. If blocks are split or missing, change detection controls. If blocks look correct but sound late, inspect the instrument and audio-buffer path in your music app.

Whole pattern drifts: check tempo
Starts miss the grid: check quantize
Notes split early: check detection
Blocks look right: check playback

Decision path separating MIDI event timing, detection fragments, and playback latency — Use what you can see in a MIDI editor to separate stored event timing from playback delay.

CONTROLLED RETEST

Convert the same passage again

Keep the source fixed, change one control, and compare the same note starts in the same MIDI editor.

INPUT MP3 / WAV / M4A / FLAC / OGG → OUTPUT .MID

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Choose audioMP3, WAV, M4A, FLAC, or OGG · one file · up to 50 MB / 5 minutes

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Observed symptom	Most direct test	Change one thing	Stop condition
Spacing drifts farther from the beat over time	Compare the source tempo with the exported MIDI tempo	Set Tempo to the source BPM, then export again	Equivalent beats stay aligned across the passage
Note starts sit between intended grid lines	Compare Quantize Off with one named grid	Select the smallest grid that represents the rhythm	Target starts align without erasing pickups or syncopation
One held note becomes several short notes	Inspect note blocks before changing the grid	Raise Minimum note in one step	Fragments merge or disappear while real short notes remain
Quiet sounds trigger early or late extra notes	Compare the same passage at one higher threshold	Raise Silence threshold in a small step	Quiet false events disappear and the melody remains
Blocks are on time but audio playback sounds late	Use the editor playhead and block positions as the reference	Test a lighter instrument or lower audio buffer in the editor	Sound follows the same unchanged MIDI blocks more closely

Four-stage MIDI timing test sequence that keeps the source fixed and changes one variable — A one-variable sequence keeps tempo, grid, detection, and playback causes from being mixed together.

TEMPO METADATA

Tempo changes tick-to-time mapping

The current writer uses 480 ticks per quarter note and calculates ticks per second from the selected BPM. A wrong BPM can make the exported pattern drift relative to the audio timeline.

GRID TIMING

Quantize changes the downloaded MIDI

The writer rounds event ticks to the selected grid. The on-page piano roll shows detected notes before file writing, so inspect the downloaded file when testing quantization.

DETECTION

Fragments are not a tempo problem

Minimum note, threshold, and pitch range determine which detected events survive. Fix split or missing blocks before judging their grid placement.

PLAYBACK

Sound delay can leave MIDI unchanged

If blocks align with the playhead but the instrument sounds late, the stored events may be correct. Test the destination instrument and audio path without reconverting.

QUICK ANSWERS

MIDI timing issue questions

Why does my converted MIDI drift out of time?

A tempo mismatch is the first thing to test when the offset grows across the passage. Set the export tempo to the source BPM and compare the same beats again.

Why do MIDI notes start too early or late?

Inspect whether the blocks are off-grid, fragmented by detection, or correctly placed but delayed during playback. Each symptom needs a different adjustment.

Should I change tempo or quantize first?

Match tempo first because it defines the tick-to-time relationship. Then compare Quantize Off with one grid setting.

Can quantization fix broken note detection?

No. Quantization moves the timing of accepted events. It does not restore missing pitches or combine unstable detections into the intended melody.

Why is the preview unchanged after I select a grid?

The preview uses detected notes before the MIDI writer applies grid snapping. Download the file and inspect it in a MIDI editor.

Download the MIDI timing test sheet (.csv)