The two-quad duet — motor music with a friend

You've maybe read the polyphony post — four ESCs on one quad playing different lines. Here's the escalation: two quads, eight motors, two pilots, one song. The quad-band, if you will.

I want to be upfront: this is a party trick with a terrible effort-to-runtime ratio. It's also the most fun I've had on a bench this year.

The arrangement

Split the song across the two quads the way an arranger splits parts:

• Quad A: the melody. All four ESCs in unison (or chorded if you're ambitious).
• Quad B: the accompaniment. Bass line on two motors, a harmony line on the other two.

Pick a song where the accompaniment is famous on its own — that's the trick. If quad B's part is generic root notes, the duet just sounds like a quad playing near a buzzing quad. Songs that work:

• Seven Nation Army — quad B carries the iconic bass riff, quad A answers with the vocal line.
• Pachelbel's Canon — the canon structure means quad B literally plays what quad A played, two bars later. The piece does the arranging for you.
• Super Mario theme — the bassline is nearly as recognisable as the melody, and the swing rhythm hides small sync errors.

The synchronisation problem

Here's the hard part. There is no link between the quads — no shared clock, no start signal. Your synchronisation mechanism is two humans pressing arm switches.

What makes it survivable:

• Count in out loud. "Three, two, one, arm." Practise the count a few times; you'll converge on maybe ±100 ms between you.
• Pad the start. Begin both RTTTL strings with a rest (4p or 2p). Arm timing scatter hides inside a silent lead-in far better than inside the first note.
• Slow songs forgive. At 100 BPM, being 100 ms apart is a sloppy-but-musical "loose ensemble feel". At 180 BPM it's a train wreck. Tempo picking advice applies double here.
• Same firmware on both quads. Bluejay and AM32 don't render tempo identically, and even different Bluejay versions can drift on long tunes. Matching firmware keeps both quads' internal clocks honest. Drift is why duets should be short: over a 10-second tune, a 1% tempo mismatch is imperceptible; over 40 seconds it's a round.

Rehearsal, unironically

Bench both quads side by side, arms toward the audience, and run it five or six times. You're rehearsing the humans, not the machines — the ESCs play identically every time. After a few runs you'll find the count-in rhythm that lands you together.

Then record it. A synced take is genuinely hard to get and worth keeping; and honestly, the outtakes where one quad comes in a bar late are half the entertainment.

Why this is worth an evening

Because the reaction is different in kind, not just degree. One singing quad gets "ha, that's cute". Two quads trading phrases of Seven Nation Army gets a small crowd, and someone always asks how they're networked. They're not. That's the punchline: the entire sync layer is two people counting to three.

Grab a friend, pick a two-part song from the library, and split the score. Quad-orchestra recruitment starts at two.