Maestro, criterion by criterion.

Criterion 1

Product–market fit

10 pts

A real, growing problem: DJs increasingly perform with a live sax, violin or trumpet player, and that player has no view of the set.

The problem

The musician improvises by ear. Every mix changes the key and tempo, and their only cue is a nod across a dark, loud stage.

Who uses it

DJ + live-instrument acts at clubs, residencies, hotels, rooftops, weddings and events.

Why they come back

It's needed at every gig: the musician opens it on their phone as soon as the DJ starts, and the DJ cues from the plugin they've already loaded.

Fits today's rig

It's built on djay Pro's OSC output and runs as a standard Audio Unit inside djay. The musician uses the phone they already carry. There's no new hardware and no account.

Business model

The musician app is free; the DJ buys the Maestro Cue plugin. Venue licences can follow.

Criterion 2

Originality

10 pts

To our knowledge, Maestro is the only tool that gives a live player the DJ's key transposed for their instrument, together with cues sent from the booth.

Today's options	Key in my instrument	Cue from the DJ	Live tempo & beat
Hand signals, shouting	No	Unreliable	No
In-ear talkback	No	Voice only	No
Shared BPM or key displays	Concert key only	No	Yes
Maestro	Yes, C, B♭, E♭ or F	Stop · Ready · Play	Yes, plus waveform

Criterion 3

Artistic potential

10 pts

Maestro turns a DJ and a musician into a real duo, and makes performances possible that today rely on luck.

Fearless key changes

The DJ can mix across keys mid-set; the musician sees the new key in their own instrument the moment the mix lands.

Cue-driven arrangements

Solos in the breakdown, hits on the drop, laying out for the vocal: all called from the booth with Ready warning what's next.

Any set, any player

A musician can join a DJ they've never played with, on tracks they don't know, and still come in on time and in key.

Shown live

Our demo is a live performance: the DJ plays, cues Ready on the build and Play on the drop, and the saxophonist comes in, in key.

Criterion 4

Demo & clarity

5 pts

It's running live, and you can try it yourself right now.

What we built during the hack

• Maestro Cue plugin: a JUCE Audio Unit (AU and AUv3) for djay Pro that sends Stop / Ready / Play cues and the live waveform over OSC, with audio passed through untouched.
• Musician app: a phone and iPad web app with a local Node OSC bridge. It follows the crossfader, transposes the key, and shows the beat, waveform and next track.
• Shared design system: one set of tokens generating both the web and the JUCE themes, in light and dark.
• Tested: 24 web tests plus native plugin tests, including a QR code decoded independently, and Apple's AU validation.