Audio to MIDI in FL Studio: when the conversion runs but no file appears.

After the pitch detector finishes, the converter checks how many notes it found. Two checks run in order, and both abort the download:

• Zero notes: the status reads "No clear notes were detected. Try a louder, cleaner, single-note recording."
• One or two notes: the status reads "Only a few notes were detected. Try a longer, clearer melody before downloading."

Neither message is a suggestion about sensitivity. The file is not written. The download link stays hidden. The user sees text where a download button should be.

This was tested with synthetic sine tones fed through the detector's Node replica — same frame size (1024 samples), same hop (256), same RMS threshold, same minimum-duration filter, same pitch search range (55–1,400 Hz). Three signals, each at peak amplitude 0.5, 44.1 kHz mono, 50 ms fade in and out:

Three sensitivity levels (More notes, Balanced, Fewer notes) produced identical results in every case. The gate does not care about the sensitivity slider — it counts notes, and the threshold is three.

The one-note case is the one that catches people. A 2-second sine at 220 Hz is a perfectly clean signal. The detector finds it, assigns it MIDI 57 (A3), and the note passes the duration filter. Then the gate kills it. The message says "try a longer, clearer melody," but length and clarity were not the problem — the count was. A single sustained note, no matter how clean or how long, will not clear a three-note minimum.

The limit of this test. The inputs are synthetic sines with constant envelopes and no harmonics — the easiest possible signal for the detector. A real recording of a single sustained note (a held violin note, a long drone, one vocal syllable) may produce the same outcome: one detected note, blocked at the gate. But it may also produce zero notes if the signal falls below the RMS threshold, or if harmonics confuse the pitch tracker into reporting pitch jumps that split one note into fragments. The gate behaviour — fewer than three means no file — is a code constant and holds regardless of input. What varies with real audio is whether you land in the zero-note bucket or the one-or-two-note bucket on the way to being blocked.

Test conditions. Three synthetic WAV signals generated as 16-bit PCM, 44.1 kHz mono, peak amplitude 0.5, 50 ms linear fade in and out. Frequencies: 220 Hz (A3), 329.63 Hz (E4), 440 Hz (A4). Detector parameters replicated from converter.js: frame size 1024, hop 256, RMS threshold [0.009, 0.015, 0.023] for sensitivity levels 1/2/3, minimum note duration [0.055, 0.075, 0.11] s, pitch range 55–1,400 Hz, MIDI range 28–96. Gate logic replicated from converter.js lines 129–130. Not tested in FL Studio itself; the gate fires before any DAW is involved. Log: localmidi-private/logs/gate-threshold-2026-11-07.txt.

Once the gate passes, the converter writes a Standard MIDI File (SMF) format 0, single track, 480 ticks per quarter note, 120 BPM. No tempo map, no time signature, no program change — just note on/off events with pitch, start tick, and velocity. The file extension is .mid.

In FL Studio, you can drag this onto the Playlist or into a MIDI Out channel. The notes will appear in the Piano Roll. Two things to set immediately:

• Match the project tempo to 120 BPM before aligning anything else. The MIDI file assumes 120. If your project is at a different tempo, the notes will look stretched or compressed. Set the project to 120, align the MIDI to your audio, then change tempo if needed. Details on why this matters are on the timing drift page.
• Do not quantise first. The detector's frame hop is 256 samples at 44.1 kHz — about 5.8 ms. Each note onset can land within that window of its true position. Quantising before you hear the result will snap notes that are only a few milliseconds off, and you will not know which ones were close and which were wrong. Listen first, then quantise the ones that need it.

If notes are missing — a note you can hear in the audio that did not appear in the MIDI — that is a detection gap, not an import error. Short notes (under 55 ms at the most sensitive setting) are filtered out before the gate runs. See the missing notes page for the duration thresholds and why they are not adjustable.

If the pitches are wrong — a note that should be E4 shows up as F4 — the detector's lag search rounds to the nearest integer sample, and at certain frequencies the nearest lag is one semitone off. This is documented with measured frequencies on the wrong notes page. The fix is manual correction in the Piano Roll, not a different sensitivity setting.

The three-note minimum is not a quality judgement — it is a safety check. A one-note MIDI file is not a melody; it is a single event. The converter assumes you came here for a transcription of a melodic line, not a sustained drone, and refuses to hand back something that will look broken in a Piano Roll.

If your audio is a single sustained note, the converter is not the right tool. You already know the pitch; enter it directly in the Piano Roll.

If your audio is a short phrase of two notes, you have two options:

• Record a longer phrase. Three notes is the floor. A five-note melody gives the detector more to work with and you more to verify against the original.
• Play the two notes twice. Repeat the phrase. The detector will find four notes, the gate passes, and you delete the duplicates in the Piano Roll.

If your audio is a full melody and you still see "Only a few notes," the problem is usually one of three things: the recording is too quiet (the RMS threshold filtered most frames), the notes are shorter than the minimum duration (55–110 ms depending on sensitivity), or the source is polyphonic and the detector tracked one note where it should have tracked several. The conversion guide walks through each case; the accuracy page shows what to check in the output.

One thing that does not help: changing the sensitivity slider. The test above showed identical note counts across all three levels for the same input. Sensitivity changes the RMS threshold and the minimum note duration, not the gate. If the detector finds one note, it finds one note at every sensitivity.

This page answers one question: I converted my audio and got no MIDI file — why? The answer is a hard-coded gate that blocks outputs with fewer than three notes. It is not specific to FL Studio, but the symptom surfaces most often when you are trying to import into a DAW and find nothing to import.

The converter was not tested inside FL Studio. The gate fires in the browser, before any DAW is involved, so the DAW does not change the result. What FL Studio adds is the Piano Roll where you correct the output — pitch errors, timing drift, missing notes — after the file is written. Those corrections are covered on the pages linked above, not here.

This page does not cover:

• How to set up a MIDI Out channel in FL Studio (that is in FL Studio's documentation).
• Whether FL Studio's own audio-to-MIDI tools are better or worse than a browser converter (not tested).
• How to route MIDI between plugins (not relevant to the conversion itself).

What it does cover: the exact threshold that stops a file from being written, the message you see when it happens, and the shortest path to getting past it.