The short answer: every source on this page — singing, whistling, beatboxing, violin, acapella, saxophone — goes through the same detector, and what comes back is governed by the same three numbers. The detector hears 55 Hz to 1800 Hz in monophonic mode (one pitch at a time) or 55 Hz to 4000 Hz in polyphonic mode (up to 6 pitches per 11.610 ms frame). A source below 55 Hz is silent to it; a source above 4000 Hz is past the ceiling. What survives in between is decided not by the instrument name but by timbre: a bright sound with strong upper harmonics can push the salience gate under 0.20 and lose notes a darker sound keeps. Singing to MIDI works well in the middle of a vocal range and fails at the extremes — the same pattern as every other source here. Where we have measured a specific source, the number is below; where we have not, we say so rather than guess.
The three numbers every source on this page shares
Before looking at any individual source, it helps to know what the detector actually does. This converter resamples audio to 22 050 Hz, reads it with a 2048-point FFT stepped 256 samples at a time, and produces one frame every 11.610 ms. In monophonic mode it tracks a single pitch inside 55–1800 Hz; in polyphonic mode it scans 55–4000 Hz and keeps up to 6 spectral peaks per frame. A candidate peak must reach 0.14 − 0.11 × sens of the frame's loudest peak — 7.4% at the default sensitivity of 60 — or it is discarded. That is the salience gate.
None of those numbers change when you switch from singing to whistling to violin. What changes is whether the source's fundamental and harmonics land inside the band and above the gate. The pages below break that down source by source.
Singing to MIDI
A sung note is a single moving pitch with a harmonic series shaped by the vowel's formants. In monophonic mode the detector follows that pitch well inside the 55–1800 Hz band, which covers the singing range of most voices — bass low notes start around E2 (82 Hz), soprano high notes reach C6 (1047 Hz). The measured failure mode for singing is the octave jump: when a vowel's formant pushes the second harmonic above the fundamental in the spectrum, monophonic mode mistakes 2× the pitch for the fundamental and the note jumps an octave. On this converter that happens at A3 (220 Hz) with as little as 1.70 dB of formant boost. The full measurement is on the vocal to MIDI page.
For acapella to MIDI, the same detector applies. An acapella recording is a solo voice with no backing instruments, which means the signal is clean and the noise floor is low — both conditions that help detection. The octave-jump risk remains, and vibrato wider than ±58 cents will cause the note to vanish. Record close, sing with a steady vowel, and convert in monophonic mode for the cleanest result.
Melody to MIDI
“Melody to MIDI” is not a different source — it is any single-line audio played or sung one note at a time. The detector does not know whether the input is a whistle, a hummed phrase, or a solo instrument. What it sees is a sequence of pitches in the 55–1800 Hz band, one at a time, and what it returns is a note list with the same seven CSV columns and the same format-1 MIDI file as every other conversion. If your melody sits inside the band and the recording is clean, the extraction is the same as the sine-scale test: 8 of 8 notes found, 0 invented.
Two things break a melody to MIDI conversion that are not about the melody itself. Accompaniment adds extra notes in polyphonic mode — if you convert a melody with a backing track, the detector finds the backing too. Fast passages under 60 ms are filtered out by the shortest-note setting. Convert the melody alone, in monophonic mode, with the shortest note at or below 60 ms.
Whistle to MIDI
A whistle is close to a pure sine wave with weak harmonics, which makes it one of the cleanest sources for pitch detection. The fundamental of a typical whistle sits between 500 Hz and 2500 Hz, comfortably inside the monophonic band up to 1800 Hz and inside the polyphonic band to 4000 Hz. A high whistle above 1800 Hz is past the monophonic ceiling but inside the polyphonic ceiling, so polyphonic mode will find it where monophonic mode will not. We have not run a measured whistle test on this converter, so we are not putting a recall number on this section — but the frequency range and the near-pure harmonic content are both favourable conditions for the detector.
Beatbox to MIDI
A beatbox is the one source on this page that does not fit the single-pitch model. Kick and snare sounds are broadband transients — they do not have a stable fundamental the detector can lock onto. In polyphonic mode, a transient fills many FFT bins at once, and the peak picker may report several short notes across the spectrum, none of which correspond to a real pitch. In monophonic mode, the same transient produces one short, arbitrary pitch or nothing at all. The detector's 55 Hz floor means a kick drum's fundamental (often 40–60 Hz) is at or below the edge of the band. This is the same problem covered on the drums to MIDI page: a pitch detector does not have a pitch to find.
What a beatbox to MIDI conversion can return is the rhythmic envelope — the timing of hits — if the shortest note is set low enough (60 ms or below) and sensitivity is raised. But the pitches will be spectral artefacts, not the sounds you made. For rhythmic extraction, a tempo and onset tool is a better fit than a pitch tracker.
Violin to MIDI
A violin's range runs from G3 (196 Hz) to E7 (2637 Hz), which straddles both detection bands. The four open strings — G3, D4, A4, E5 — sit inside the monophonic band. Notes above A6 (1760 Hz) are past the monophonic ceiling and only visible in polyphonic mode. E7 (2637 Hz) is inside the polyphonic band. The measured behaviour on this converter's own analyser: G3, A4 and E5 came back correctly, while D4, A5, E6 and A6 — all comfortably inside the band — were dropped for scoring under the 0.20 salience gate. That is a timbre effect, not a pitch-range problem: a bowed string's brightness changes with bow speed and bow position, and that brightness is the lever that moves the salience score.
The full violin measurement, including the salience scores for each tested note, is in the violin section of the piano to MIDI page, which covers multiple instruments under the same detector.
Saxophone to MIDI
A saxophone's range runs from Bb3 (233 Hz) up to altissimo notes above C6 (1047 Hz), all comfortably inside the 55–1800 Hz monophonic band. The timbre is bright and harmonically rich, which means the salience gate is the main risk — a bright, closely miked sax with strong upper harmonics may push individual notes under the 0.20 threshold. We have not run a measured saxophone test on this converter, so we are not giving a recall number here. What we can say from the mechanism: the fundamental is inside the band, the harmonics are inside the polyphonic ceiling, and the sensitivity slider is the lever that moves the salience gate. If a note is missing, raise sensitivity and watch whether it returns as one note or as fragments.
Instrument to MIDI: the general case
If your instrument is not named above, the answer comes from three questions: Is its lowest note above 55 Hz? If yes, the fundamental is inside the band. Is its highest note below 1800 Hz (mono) or 4000 Hz (poly)? If yes, the top is inside the band. Is its timbre dark or bright? Dark sounds convert more reliably because their harmonics do not pull the salience score under the gate; bright sounds lose notes in the middle of their range where the pitch itself is fine. Every instrument to MIDI conversion on this detector follows those three rules, and the pages for piano, guitar, drums and bass each measure them in detail.
Questions
Can I convert singing to MIDI?
Yes. Singing is one of the cleaner sources for this converter because it is a single moving pitch. Use monophonic mode, record close with a steady vowel, and watch for the octave jump that happens when a formant pushes the second harmonic above the fundamental. The full measurement of that jump is on the vocal to MIDI page.
Does whistle to MIDI work?
Yes, and it is one of the easier sources. A whistle is close to a pure sine wave, so the detector's pitch tracker locks onto it cleanly. The fundamental of most whistles sits between 500 and 2500 Hz, inside both detection bands. A very high whistle above 1800 Hz is past the monophonic ceiling but inside the polyphonic ceiling. We have not run a measured whistle test, so we do not give a recall number for it.
Can beatbox to MIDI capture the rhythm?
The timing of hits can come through, but the pitches will not. A beatbox kick and snare are broadband transients without a stable fundamental, so the pitch detector reads them as short spectral artefacts. For rhythmic extraction, a tempo and onset tool is a better fit. The drums to MIDI page covers the same problem in detail.
What instruments does this converter support?
Any instrument whose notes sit inside the 55–1800 Hz band (monophonic) or 55–4000 Hz band (polyphonic). The detector does not know the instrument name; it reads pitches. Piano, guitar, violin, bass, voice, whistle and saxophone all sit inside that range. Drums do not, because they do not have a stable fundamental. See piano to MIDI for the measured range limits per instrument.
Will an acapella recording convert better than a mixed vocal?
Yes. An acapella recording is a solo voice with no backing, so the signal is clean and the detector has one pitch to follow. A vocal inside a full mix competes with other instruments, and in polyphonic mode the detector will find those too. Convert the vocal alone for the cleanest result.
Convert your recording to MIDI — drop a vocal take, a whistle, or any single-line audio and get a .mid back in the browser.
Related guides
- Vocal to MIDIWhy a sung note comes back an octave up
- Voice to MIDIWhat a single-line converter can follow
- Humming to MIDIWhat wordless vocals come back as
- Piano to MIDIWhere the keyboard falls outside the detector
- Guitar to MIDIWhat a bend does to your notes
- Drums to MIDIWhat a pitch detector does with no pitch to find
- Microphone to MIDIWhat this converter does with a recording