Turning a hummed melody into MIDI in the browser: a step-by-step walkthrough

You have a melody in your head, a voice memo on your phone, and a DAW waiting for notes. Typing those notes into a piano roll by hand is slow. This walkthrough shows how to get a first MIDI draft from a short recording using a free audio to MIDI converter that runs entirely in the browser, and how to clean up the result afterwards.

Disclosure: I work on MusicFX, the site that hosts this tool.

What the tool does (and what it does not)

The converter estimates pitched notes from a recording and writes a standard .mid file. Each note carries pitch, start time, duration and velocity. It does not keep the sound of your voice or guitar: MIDI is note data, so you assign an instrument after import.

A few practical facts before you start:

• It runs locally. The page loads its model files on first use, and your recording stays on your device; nothing is uploaded to a server.
• No account is needed.
• Input: a browser-decodable MP3, WAV, FLAC, OGG, AAC or M4A file (MP4 and WEBM are also accepted), up to 80MB and 2 minutes.
• It can miss notes or add false ones, so plan on a short editing pass.

Step 1: Record something the model can read

Short and clean beats long and busy. A solo voice, a single guitar line or a few piano chords work far better than a full mix with drums. If you hum, keep a steady volume and avoid room noise. Trim silence at the start so the first note lands near zero.

Step 2: Pick a detection mode

There are two modes:

• Clean Melody – for one voice or one lead instrument. Use this for hums, whistles, sung toplines and solo lines.
• Chords – for harmony, such as guitar strums or piano chords, where several notes sound at once.

Step 3: Tune the two sliders

Note Sensitivity (default 50) decides how eagerly the model reports notes. Higher values catch quiet notes but may add false ones. Lower values give a sparser, cleaner file.

Minimum Note Length ranges from 40 to 400 ms (default 120 ms). Raise it to drop short fragments and flutter; lower it if fast passages are disappearing.

A sensible first pass: Clean Melody, sensitivity 50, minimum length 120 ms. Convert, listen, then adjust one slider at a time.

Step 4: Decide on the three options

• Write Estimated Tempo adds a tempo estimate to the file so notes line up sensibly with your DAW grid.
• Snap Notes to Grid (beta) quantizes timing. It makes editing easier but removes expressive timing, so leave it off if you want the feel of the performance.
• Include Pitch Bends keeps slides and vibrato. Useful for vocals and bends on guitar; turn it off if you want plain, stepped notes.

Step 5: Convert and download

Click Convert to MIDI, then download the .mid file. It opens in Ableton, FL Studio, Logic and other DAWs or notation apps.

Step 6: Clean up in your DAW

Expect to do three small jobs:

1. Delete ghost notes. Very short, quiet notes are usually false positives.
2. Fix octave slips. Hummed notes sometimes land an octave off; select and transpose them.
3. Assign an instrument. Pick a synth, piano or bass and play it back against the original recording to check timing.

If too many notes are missing, go back and raise sensitivity. If there is too much clutter, raise the minimum note length instead.

Where this fits in a workflow

• Producers re-voice a sampled riff or turn a hummed idea into a bassline.
• Songwriters turn a voice memo into a melody before it is forgotten.
• Students check an ear-training guess by viewing a solo on a piano roll.

Related free tools

If you also need the tempo or key of the same recording, the same site has a key and BPM finder and a BPM detector that also run locally. You can browse them from the MusicFX home page.

MusicFX is an independent music platform and is not affiliated with any DAW or plugin maker mentioned here.