Why did the AI arrangement change my melody?

An AI arrangement can change your melody because it generates a new performance from a reference; it does not necessarily lock the original notes or retain the original audio. SoundToMIDI does not guarantee exact melody, timing or duration preservation. Before paying for another generation, identify whether you dislike the new instrument, the timing, or the actual sequence of notes. Each problem calls for a different response.

If the requirement is “keep every note exactly as written,” a generated arrangement is the wrong finishing tool. Keep your recording or work from corrected MIDI in a DAW, where you can edit and lock the melody yourself. Use generation when exploring a new musical direction is acceptable.

First decide what must stay unchanged

Three requests that sound similar lead to different workflows:

What you need	Practical route	What SoundToMIDI currently provides
A new instrumental interpretation of a recording	Generate an arrangement and compare the delivered versions	Four style presets, mixed MP3 output, 5 credits per request
Your exact recorded performance with accompaniment underneath	Keep that recording on an audio track and build separate accompaniment	The arrangement tool does not promise to preserve the original audio track
The tune as notes you can change	Transcribe, correct the notes and assign an instrument in a DAW	Free local audio-to-MIDI conversion and Raw MIDI download

This distinction also explains conflicting advice about music tools. Suno’s Cover page describes a style transformation with the melody as its reference. Autunes’ guide instead distinguishes a retained vocal take from generating around a hummed idea. These are the companies’ descriptions, not our independent performance tests. Neither establishes what your particular file will produce in SoundToMIDI.

Compare one phrase, then the full result

Open the original and generated audio separately. Pause one before playing the other; listening to both at once makes errors harder to identify. Start with a phrase you can hum from memory. Keep playback at a comfortable, roughly similar loudness so that a louder arrangement does not win by default.

Listen in this order:

1. Phrase shape. Where does the tune climb, fall or repeat? A changed instrument can sound unfamiliar even when the contour is recognizable.
2. Important pitches. Check the longest note, the highest note and the last note. Do they land where you intended? An entire line moved by an octave is different from several notes changing relative to one another.
3. Rhythm. Are note lengths and gaps still recognizable? New drums can change the feel without changing the tune, but shortened rests can alter the phrase itself.
4. Later sections. Repeat the comparison beyond the opening. Do not accept a result solely because its first few seconds resemble the source.
5. Ending and usability. Does the result stop cleanly? Does its duration fit your use? Does it contain sounds you did not want?

Write one concrete observation, such as “the last note of the second phrase is different.” “It sounds wrong” is difficult to act on. A specific observation helps you decide whether a new input is worthwhile or whether you need manual editing.

Choose the fix that matches what you hear

Symptom	What to inspect	Useful next step
The tune is buried in the recording	Backing music, loud chords, another singer or room noise	Record a clearer solo phrase or export the isolated melody track you own
The result is recognizable but has the wrong mood	Compare the actual preset demo, not just its picture	Try a different preset only if you accept a new 5-credit request
The opening matches but a later phrase wanders	Listen at the point where it changes; check whether the source makes that phrase clear	Try one complete, clear phrase; do not assume repeated generations will repair a specific note
Every phrase must use exact pitches and timing	Check whether this is an arrangement experiment or a transcription task	Use corrected MIDI or retain the original recording in a DAW
The file will not load	Duration, file size and browser decoding	Use 8–120 seconds, at most 25 MB; export WAV or MP3 if needed
The job is still processing or unresolved	Look in “Your arrangements” under the same account	Check the existing request before starting a new one; contact support if it remains unresolved

A cleaner input is a preparation step, not a guarantee of a faithful result. Do not keep buying attempts on the assumption that the next one must preserve your melody. The current page offers four style presets; it has no note-lock switch, chord-progression editor, audio-influence slider or text-prompt field. Advice about those controls in another product will not apply here.

Use the free route when notes matter more than production

For a melody that must remain editable, open the humming-to-MIDI converter or another matching input page. Convert the source locally, then compare the piano-roll notes against the recording before downloading Raw MIDI for free. A transcription can still contain extra notes, missing notes or octave mistakes; it is a starting point you can correct, not proof that every pitch is right.

Import the .mid file into an instrument track in your DAW. Assign a sound, check the note positions and correct the melody before adding other parts. Keep an untouched copy of the recording alongside it. If the original performance itself must survive, use that audio as the reference track rather than replacing it with a generated performance.

You may be able to run a generated MP3 through a MIDI converter, but the new arrangement is a full mix. That extra transcription step does not recover the original source’s exact notes or produce reliable separate instrument tracks. Starting from your clean original melody is the clearer route when the goal is editable notation.

Understand a retry before spending credits

An arrangement request costs 5 shared credits, including the versions returned for that request. A new preset or another attempt is a new request. A completed track that you do not like is not a technical failure, so its credits are not automatically restored. Confirmed technical failures return credits once; the current request history is the place to check its status.

A US$4.90 or €4.90 pack provides 100 non-expiring credits, enough for 20 operations at the current 5-credit rate. Export unlocks use the same balance. There is no subscription, and existing unlocked projects stay unlocked. You do not have to buy credits to use the free converter or listen to the fixed arrangement demos.

Before retrying, change something you can name: replace a noisy recording, make the full phrase audible, or choose a different style for a different mood. If nothing about the input or goal has changed, another paid attempt is an experiment—not a known fix. For a complete first-use walkthrough and the original melody beside four generated examples, see turn your own melody into an instrumental arrangement.