Can MIDI recreate a synth sound from a song?

A typical audio-to-MIDI result is a best-effort transcription of note starts, note ends, pitches, and sometimes velocities or expressive controls. It does not contain the recorded waveform. Even a correct sequence of notes will sound different when played by a different synth or piano patch.

The MIDI 1.0 message set includes note events, program changes, controllers, and pitch bend. A program change can select a sound already available on a receiving instrument; it does not package an arbitrary synthesizer patch and its samples into a portable audio copy. Vendor-specific sound dumps are a separate, device-dependent case.

1. Find the cleanest source. Use the original DAW session or an isolated stem if available. A dense mix makes both note extraction and sound identification harder.
2. Transcribe only the part you need. Convert a short phrase with the Local MIDI tool, then compare the notes with the source. Fix missing notes, false notes, octave mistakes, and timing before judging the new instrument.
3. Look for the original patch. Check the project, preset name, plugin, sample library, and effects chain. A recovered patch is the most direct route to the original timbre.
4. If the patch is gone, rebuild by ear. Match the broad source first—synth, pluck, pad, or bass—then adjust oscillator or sample, filter, envelope, modulation, and effects. The MIDI supplies the notes while you audition the tone.
5. Use resampling only when audio is acceptable. A short isolated note can be mapped in a sampler, but loops, modulation, note transitions, and chords may not behave like the original synth across a keyboard.

If your goal is to hear the same recording again, keep and arrange the audio. If your goal is to change the melody or trigger a different instrument, MIDI is useful—but it is not a sound-recovery format.

On October 26, 2026, five openly licensed Internet Archive recordings were tested through the live Local MIDI converter in Chrome at the default “Balanced” sensitivity. Each original MP3 was decoded to 44.1 kHz stereo PCM and the opening excerpt was saved as WAV before selection: 15 seconds for four recordings and 3.553 seconds for the short drum loop. The timer runs from clicking Convert to the page's final result message in this browser session; these are not device-independent speed benchmarks.

What this test does not measure: these five runs measure note-event output only. They do not test whether a converter can recreate a synth patch, sample, filter, envelope, effects chain, or the original tone. There is no independent tone-recovery reference in these recordings, so that part is not measured here.

Sources and licenses: MHMonk Solo Guitar November 2000 (CC BY-SA 4.0); Humming girl (CC0 1.0; archive description: “girl hums tune”); Drum test loop MAX (CC BY 2.5); Happy Birthday Rap (Stems) ft Donnie Ozone (CC BY-SA 3.0; full mix); and Stratton, Vermont field recording (Public Domain Mark 1.0). No source audio is redistributed on this page.

Important limit: the source descriptions identify the recordings, but none came with an independent note-by-note reference for these excerpts. Event counts are only what the converter emitted; they do not tell us how many notes were missed, added, placed in the wrong octave, or shifted in time. The Stratton file is environmental field audio rather than a live music performance. These five runs document specific inputs and outputs, not a universal accuracy claim.

One concrete boundary: the 3.553-second drum loop produced only three note events in this run. For drum material, that output is not a usable drum transcription; a dedicated drum-transcription workflow is the better route than treating this monophonic note detector as a way to split a kit.

Try a short passage in the Local MIDI converter; keep the original audio beside its MIDI and verify the notes before using them to rebuild a sound.

• Change notes or play another instrument: convert to MIDI and edit the events.
• Keep the exact synth tone: locate the original patch or retain the audio/stem.
• Recreate a similar tone: use MIDI as the note source and build a new patch by ear.
• Extract a synth from a finished song: source separation may help expose a part, but it does not reveal a guaranteed original preset or settings.

This page describes the file-format distinction and a workflow; no synth-identification or patch-recovery benchmark was run. The result of rebuilding a tone depends on the source, available instruments, and how closely you need to match it. Try the Local MIDI converter on a short melodic passage, then use the original audio as your reference while you rebuild the instrument sound.

Reference: MIDI 1.0 Detailed Specification describes channel messages including Note On/Off, Program Change, Control Change, and Pitch Bend. They communicate performance and control data; the receiving sound generator produces the audio.