PRISM PRO: key, scale and pitch sources
Four ways to decide which note PRISM PRO plays, in a fixed order, and what each one costs.
Four sources, one order
PRISM PRO never has to be told what to play: the engine follows the pitch of the voice it hears. But you can take that decision off it, three ways, and the order between them never changes. MIDI outranks the chord PRISM PRO hears on its sidechain, which outranks the key and scale you set, which outranks the follower running free. Whatever is highest on that list is what is driving the line, and the sentence beside the lists always says which one it is. PRISM PRO is this plugin's name from version 1.2.2 on; it was called PRISM up to that release, so an older install still reads Nolvra PRISM in your plugin browser. The bundle identifier did not change with the name, so a saved project finds it either way.
The order
- MIDI. You play the pitch. Nothing is quantised, because you already chose the note.
- AUTO. PRISM PRO hears the chord on its sidechain and snaps the line to the notes in it.
- KEY and SCALE. Every note the engine decides on is quantised into the scale you set.
- Free. The follower drives on its own and OCTAVE picks which octave it sits in.
Key and scale
KEY is the root, twelve of them. SCALE is CHROMATIC, MAJOR, MINOR or AUTO. CHROMATIC is the off position and it is what comes out of the box: no quantising, the note is whatever the follower decided.
Set a major or a minor scale and the engine's decisions land inside it. Measured on real material, out-of-scale decisions go from 12.1% to zero, and the cost is visible too: the line holds the source pitch slightly less of the time, 72.4% against 67.4%. That trade is the point of the control.
SCALE: AUTO works the key out from the engine's own note decisions, weighted by how long each note is held. The KEY box dims, because the detector is picking the root. The line then reads either AUTO KEY: C# MAJOR - SNAPPING, or, when it has not gathered enough evidence yet, AUTO KEY: LISTENING - NO QUANTIZE YET. It will not quantise before it has decided. A wrong lock is worse than no lock.
Chords from the track
Connect the song, or the channel playing the chords, to PRISM PRO's Sidechain input. The engine hears the chord, the chip names it, and the line snaps to the notes in that chord. Measured on a full mix with drums, bass, chords and vocal: the correct chord is held 87.8% of the time, the control condition transposed a semitone reads 0.0%, and a chord change lands 42 ms late.
Two behaviours worth knowing. If MIDI has arrived once, AUTO goes quiet, because MIDI outranks it. And while confidence is low the last chord is held rather than dropped, so a quiet bar does not unlock the line.
Hosts spell the sidechain input differently. In Ableton Live it is the Sidechain chooser on the left of the plugin's device strip; in Logic Pro it is the Side Chain menu at the top of the plugin window. The article on sending MIDI to PRISM PRO covers both, with screenshots.
Transpose is in scale degrees
OCTAVE is an anchor: it picks which octave the line sits in, and it moves in octaves. TRANSPOSE fills in the steps between, and its unit depends on the scale. With a scale locked it moves in scale degrees, which means its output is inside the scale by definition and a wrong note is not reachable. In CHROMATIC a degree has no meaning, so the control falls back to semitones and the label says so: TRANSPOSE - SEMI.
What MIDI changes
Once a note arrives, the keyboard plays the pitch, so nothing is quantised: OCTAVE steps aside, key and scale stop acting, and their chips dim and say why. Harmony is passive in MIDI mode in this version, for the same reason.
PRISM PRO also gives the voice back on its own. After seven seconds with no note held, the follower takes over again, so a rest in the middle of a take does not hand the whole song to a key that was released minutes ago.
One thing that deliberately does not count as MIDI: a panic. All Notes Off and All Sound Off are what a host sends when the transport changes, which includes pressing Record. Those messages never put PRISM PRO into MIDI mode, so arming an audio channel cannot silently take the follower away from you.
Presets do not touch your key
KEY and SCALE sit outside what a preset carries. A preset holds a sound, not the song you are playing it over, so choosing your song's key once is enough and no slot takes it back. The MODIFIED read-out ignores them for the same reason: a preset never asked for your key, so your key is not a change to it.
Still stuck?
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