How to Turn a Voice Memo Into a Song, Without AI

To turn a voice memo into a song, find the note your tune keeps coming home to, because that note names the key, and put a chord from that key under each bar’s longest note. Then decide whether the memo is a verse or a chorus, write the section it is missing, and record a demo at a steady tempo with the memo as your guide. You can do all of it by ear on a phone, and every choice in the finished song is yours.

Step 1: find the key of your voice memo

Protect the original first. In Voice Memos, trim to the best take and tap Save as New Recording, which leaves the original untouched.

Now find the home note, which theory calls the tonic. Pause the memo on its last long note, hum it back, and hunt for it on a keyboard or piano app until the two sound like one note. If matching by ear is slow, hum into a chromatic tuner app and read the letter off the screen. Hummed notes wander, so a reading like “A, 30 cents flat” means A. If every note reads about 40 cents flat, the whole memo sits between two keys. Take the nearer one, since you will sing the melody fresh for the demo in step 4.

To test the guess, hold that note on the keyboard while the memo plays. The last line should sound settled over it. If it sounds like a question, try the note the melody lands on most often.

Next, major or minor. Count up from the home note in half steps, black keys included. If the melody uses the note four half steps up, the key is major: with C as home, that note is E. If it uses the note three half steps up (Eb over a home of C), the key is minor. If a short hook skips that note, play a major and a minor chord on the home note under the memo and keep whichever matches the mood.

Once you have a key, these are the four chords to try first in six common major keys:

For a minor memo, find the row whose last chord is your home note, and treat that minor chord as home. A home of E points to the G major row, so your chords are Em, C, G and D. For a stronger ending, put a major chord on the scale’s fifth note just before the last chord: B major before a final Em, E major before a final Am. Keys not in the table are on the chord charts for all 24 keys.

Step 2: put chords under the melody

Find the beat first: tap your foot along with the memo and count 1, 2, 3, 4. If the count wants to be 1, 2, 3, the memo is in 3/4, a waltz feel. Chords usually change on the “1”, every bar or every two bars.

Go through the memo one bar at a time and find the note that matters: the one on beat 1, or the one held longest. Give that bar a chord that contains it. In C major, every scale note fits at least one of the four chords: C fits C, F or Am; D fits G; E fits C or Am; F fits F; G fits C or G; A fits F or Am; B fits G.

Say your memo is a four-bar hook in C major that leans on E in bar 1, A in bar 2, G in bar 3 and D in bar 4:

Both columns work, because each chord holds the note beside it. The moodier one swaps in the vi and iii chords, and the hook turns wistful. Ending bar 4 on G (the V chord) leaves the phrase hanging like a question. Repeat the hook with its last note moved down to C, put a C chord under it, and the question gets its answer.

Write the chords down with their bar numbers. That list is your first chord progression. To hear it against your voice, play the chords on the free online chord player in your key and hum the memo over them. On iPhone, Gelato Chord adds a second check: hold a chord on one of its seven keys and the matching strings on its melody plate light up, so you can tap the lit strings and hear which one matches the note you hummed. How to find chords for a melody covers notes that fit none of the four chords and voices that slide between pitches.

Step 3: turn the idea into a verse and chorus

A memo is usually one section of a song, so work out which one you have. A chorus hook is short and sits high, often on long notes. A verse line packs more words into each bar and sits lower. If you hummed the same short phrase twice in a row, treat it as the chorus.

If your memo is a chorus, the verse you write should sit lower and move faster. Keep its highest note at least three scale notes below the hook’s peak, so the chorus lifts off when it arrives: if the hook tops out on the C above middle C, let the verse top out around G. Give it more syllables per bar and fewer held notes; something close to talking is fine. Start it on a different chord, too: if the chorus opens on I, open the verse on vi or IV. In C, a verse of Am, F, C, G makes a chorus that opens on C sound like coming home.

If your memo is a verse, flip those rules. The chorus climbs, holds its notes longer and puts the song’s title on the longest one.

Lyrics can wait. Sing the new section on “la”, or on nonsense syllables with the same vowels as the memo, and write real words once the tune has settled. Here is a standard layout, built on the C major hook from step 2:

At 90 BPM, one bar of 4/4 lasts about 2.7 seconds, so each 8-bar section runs about 21 seconds and the whole layout comes to about two and a half minutes. Dm and Em appear nowhere else in it, which is why the bridge sounds like new ground before the last chorus.

Step 4: record a demo over your voice memo on iPhone

Find the memo’s tempo first. Tap your foot along with it for 15 seconds, count the taps and multiply by four. Twenty-three taps is 92 BPM, so set the click to 92.

A hummed memo drifts in tempo and pitch, so chords played to a click slide out of line with it within a few bars. Use the memo as a reference and record fresh: chords to a click first, then the lead vocal, then bass and drums.

You can record the demo on an iPhone in three ways:

1. Voice Memos layers. On an iPhone 16 Pro and the later models on Apple’s layering support page, Voice Memos can record a vocal on top of an instrumental memo without headphones. Record the chords as a new memo, add a second layer, and sing over it. The Layer Mix slider balances the two, and Separate Layers splits them into two .m4a recordings you can edit or share on their own.
2. GarageBand. Export the memo with Save to Files in the share sheet. In GarageBand, set the song’s tempo first, because imported audio does not follow later tempo changes, and set the song section to Automatic so the whole memo comes in. Then, in Tracks view, tap the Loop Browser button, choose Files and drag the memo onto its own track (Apple’s GarageBand import guide has the details). Record chords and vocals on new tracks, and mute the memo once you know the part.
3. Two devices. Play the chords from a laptop or tablet speaker and sing into Voice Memos on your phone. It sounds rough, and a rough demo is enough to judge a song.

On the GarageBand route, sing with wired headphones on. The mic then stays clear of the backing track, and you skip the delay that Bluetooth headphones such as AirPods add.

Keep the original memo, and play it once more before you call the demo finished. A first take often has a phrasing that gets lost by the tenth run-through.

How to turn humming into music without AI

The by-hand way to turn humming into music is to hum the other parts too, one memo per part with names like “Rain, bass”, then rebuild each memo on an instrument.

Start with the bass line. Hum it low and slow, mostly on the root of each chord: under a verse of Am, F, C, G, that means A, F, C and G, one per bar. Match its notes as in step 1; with the key known, nearly every one is among the seven scale notes. Gelato Synth suits this job: in Notes mode you pick the root and scale you found, the pads play only the notes of that scale, and with a bass sound loaded you can hunt for the hummed line without landing outside the key. Its record button saves what you play as an .m4a file to import into the demo as a new track.

For the drums, beatbox into their own memo: “boom” for the kick drum, “ka” for the snare, a quiet “ts” for the hi-hat. A bar of 4/4 is 16 steps in a step sequencer such as GarageBand’s Beat Sequencer. For the basic rock and pop pattern, put the kick on steps 1 and 9 (beats 1 and 3), the snare on steps 5 and 13 (beats 2 and 4), and the hi-hat on every odd step. Play it next to your beatbox memo, then move single kicks until the two line up.