Pachelbel's Canon on four motors — a four-voice arrangement walkthrough

Most motor-music arrangements are "melody plus bass" — two voices doubled across four motors. That works, but it wastes half the instrument. A quadcopter has four independent voices. Canon in D has four independent parts. This was always going to happen.

Here's the full walkthrough of how we arranged it, decision by decision. The finished RTTTL is in the song library if you just want to flash it — but if you want to arrange your own four-voice piece, the reasoning below transfers to anything.

Why Canon in D specifically

Three reasons make it the ideal first four-voice arrangement:

1. The voices barely move. Pachelbel's lines descend stepwise in half notes. Voice leading (each voice moving as little as possible between chords) happens automatically, which means no jarring motor-to-motor jumps.
2. The harmony is self-explanatory. D – A – Bm – F#m – G – D – G – A. Eight chords, endlessly looped. Everyone has heard it at a wedding.
3. It's public domain. Pachelbel died in 1706. Post the video anywhere.

The four lines

We assigned voices front-to-back — treble up front, bass at the rear:

Motor 1 — soprano. The famous first-violin entry: F#6, E6, D6, C#6, B5, A5, B5, C#6. All half notes. This is the line people will hum along to.

Motor 2 — alto. A third below the soprano: D6, C#6, B5, A5, G5, F#5, G5, E5. Together with motor 1 you already get parallel thirds — the prettiest interval square waves can make.

Motor 3 — tenor. The chord-completing voice: A5, A5, F#5, F#5, D5, D5, D5, E5. Notice how little it moves — four distinct pitches across eight chords. Boring on its own, essential in context.

Motor 4 — bass. The ground bass, the most famous eight notes in Baroque music: D5, A4, B4, F#4, G4, D4, G4, A4. This line repeats identically under every variation of the original piece.

Stack any column vertically and you get the full chord: bar 1 is D+F#+A+D = D major. Bar 3 is B+D+F#+B = B minor. The quad literally plays four-part harmony.

Decisions that mattered

Everything in half notes at 100 BPM. Our tempo guide usually says 140–170 BPM, but that advice is for melodic lines. Chordal music wants slower — each sonority needs time to register as a chord rather than a passing blur. Half notes at 100 BPM = 1.2 seconds per chord. Stately, which suits the material.

The bass starts on D5, not D4. The authentic ground starts an octave lower, but D3 doesn't exist in RTTTL's octave range and an all-octave-4 line got lost under the upper voices on our test quad. Starting the contour on D5 and letting it fall into octave 4 keeps the entry audible and preserves the descending shape.

Eight notes per motor. That's it. The full Canon runs several minutes of variations; we arranged one cycle of the progression. 16 bytes of a 128-byte budget. You could loop it four times and still fit — but as we argued in short songs beat long songs, one clean statement lands better than three repeats.

What it sounds like

Honestly? Like a tiny, slightly angry church organ. Square waves in four-part harmony have a distinctly reedy, harmonium-ish quality — the harmonics of each voice interlock in a way two-voice arrangements never achieve. The first time all four motors landed the Bm chord together, everyone in the room looked up.

It's also an outstanding hardware diagnostic: if one ESC's melody didn't write correctly, you hear a hole in the harmony immediately. (Our troubleshooting checklist covers what to do when that happens.)

Arrange your own four-voice piece

The recipe generalises:

1. Pick music with slow harmonic rhythm and stepwise voices — Baroque chorales and hymn tunes are ideal. Bach chorales are public domain and pre-voiced in exactly four parts.
2. Give each voice its own MIDI track, then let the converter assign one voice per motor — or pin them manually in the editor.
3. Keep all four voices within about two octaves total, ideally octaves 4–6.
4. Slow down. Chords need dwell time.