Authoring keys

Keys means electric pianos, organs and bell-like keyboards. They are played in chords, they respond to how hard you strike them, and they carry a recognisable shape: a clear attack followed by a ring that decays or holds.

Play chords rather than single notes while you work, because a keyboard sound has to hold together as a chord.

Each control below gets a start value and a range to try, and each entry says what happens when you cross an edge. The ranges come from what the instrument is, not from a survey of our presets. See how to read these tables for what the provenance tags mean.

Voice

• Voice Mode (production convention). Keyboard instruments are played in chords.

Oscillator

FM is the heart of electric-piano and bell tones. The first row below is the switch that enables it, and the rows after it do nothing until it is set to Phase FM.

• FM Mode (acoustic fact). The switch the whole page depends on. Set to Phase FM, Osc 2 modulates Osc 1's phase, and that is what produces the metallic edge on the attack that says electric piano or bell. Leave it Off and every FM row below does nothing at all: not set differently, but inert. The organ variant is the one build here that turns it off on purpose, because a drawbar organ is additive rather than inharmonic.
• FM Depth, when FM Mode is Phase FM (acoustic fact). FM adds partials that are not in the harmonic series. A little (5 to 12%) is the tine of an electric piano: a metallic edge on the attack over an otherwise harmonic tone. A lot (around 50%) is a bell, where the inharmonic partials dominate. The middle is a muddy in-between that sounds like neither, which is why the useful settings sit at the two ends.
• FM Feedback, when FM Mode is Phase FM (Kiwisynth-specific, our judgment). Operator self-feedback adds grit to the carrier. Past about 25% it reads as distortion rather than as tone.
• Osc2 Semi (acoustic fact). The modulator-to-carrier ratio decides whether the added partials are harmonic. Whole octaves keep them harmonic and piano-like. An interval such as +10 lands between harmonics and gives the clang of a bell, because partials that do not line up with the harmonic series are what the ear hears as metal.

A bell and an organ are both built from this section rather than from a different one, but each takes it somewhere the base band cannot follow. Both are written out in full under Variants at the end of the page.

Filter

• Filter Type (acoustic fact). The gentle slope. A steep filter takes the top off the attack, and the attack is how a keyboard instrument announces itself.
• Filter Cutoff, when Filter Type is LP12, LP24 or MGLow24 (production convention). Open enough that the strike keeps its edge. A keyboard instrument announces itself in the first few milliseconds, and that transient is broadband: close the filter far below 800 Hz and the strike is gone even though the tone that follows it survives.
• Filter Reso, when Filter Type is LP12, LP24 or MGLow24 (acoustic fact). Low, for the same reason the slope is gentle: a resonant peak colours the attack and a struck keyboard note should read as struck, not as filtered. The synth keys variant is the one place on this page where a higher setting is argued for, and it argues for it by dropping the claim that the sound is acoustic.

Keytrack is a modulation source rather than a filter setting, so the Keytrack routing in Movement below is made in the mod matrix rather than switched on here at the filter.

Amp envelope

• Attack (acoustic fact). A hammer or a tine strikes; it does not swell.
• Decay (acoustic fact). A struck string decays for as long as it has energy. Short for a clav, seconds for a bell.
• Sustain (acoustic fact). This one control picks the instrument. Low (around 10%) gives an electric piano, which fades while you hold the key, because a struck string has no energy source. High (around 70%) gives an organ, which holds flat until you let go, because an organ pipe keeps sounding as long as air moves through it.
• Release (acoustic fact). Lifting the key drops the damper onto the string, so the note stops soon but not instantly. It is what gives keys their familiar ring when you take your hands off a chord.

Movement

Movement over the note: front-loaded, widest at the attack, settling as the note rings (acoustic fact).

A key is a hammer or a tine, so the note is loudest and brightest at the strike and loses its upper partials faster than its fundamental as it rings. That falling brightness is most of what makes a keyboard instrument recognisable, and it is why a keys patch with constant movement reads as an organ no matter what waveform it uses.

How to build it: ModEnv1 with attack near zero, decay 0.3 s to 0.7 s and sustain low, routed to Filter Cutoff or to wavetable position.

The organ variant is exempt. A drawbar organ is a set of steady tones opened by a valve, so it genuinely does not change while the key is down. Requiring a falling brightness of it would be requiring it to stop being an organ.

• Velocity to FM Depth (acoustic fact). The main expressive link for keys, and the first one to set. A harder strike is brighter and more metallic. On an FM sound this does more than velocity to cutoff can, because it changes which harmonics exist rather than filtering the ones already there.
• Keytrack to Filter Cutoff (acoustic fact). A real keyboard is voiced brighter at the top than at the bottom, rather than every note sharing one tone.

Effects

• Chorus Mix (production convention). The classic electric-piano shimmer, and the effect that most says keys.
• Reverb Mix (production convention). A sense of room without pushing the instrument to the back.

Chorus in Ensemble mode runs several modulated voices rather than one, which is why it widens without the obvious wobble a single-LFO chorus has at these depths.

Variants

Build the base sound above, then apply the overrides below. Everything not listed stays as it was.

Bell

What the note is made of (timbre). Everything not listed below is unchanged from the base keys. A preset claims this band by declaring "timbre": "bell" in its tags; until it does, the base band still applies to it.

Inharmonic partials dominate, and the note rings for seconds. A bell is struck exactly like a piano is struck, so the articulation has not changed: what changed is the material. Metal instead of string, and the long ring follows from the material rather than from how the note was started. The FM Algorithm row below is what makes this a true bell rather than a bright piano, and it is worth understanding before you set it: Dual Pair adds a second sine pair feeding Osc 3, which gives a second, independent set of partials to put out of tune.

• FM Algorithm (acoustic fact). The two-operator stack the base build uses can only make partials that relate to one modulator. A real bell has several independent inharmonic families ringing at once, which is why it sounds like an object rather than a tone. Dual Pair supplies the second pair, and the Op 4 Ratio below is what puts it out of tune with the first.
• FM Op4 Ratio (acoustic fact). Read the decimal, not the whole number: the offset is the entire point. At exactly 7 the extra partials land on the seventh harmonic and fuse into the tone, and you have a brighter piano. At 7.02 they sit just beside it, beat slowly against it, and the ear hears metal, because partials that do not line up with the harmonic series have no pitch to fuse into. Any off-integer value works and the useful ones are a couple of hundredths away from a whole number. Land on a whole number by accident and the bell quietly stops being one.
• FM Depth (acoustic fact). Enough that the inharmonic partials are the tone rather than an edge on it.
• Decay (acoustic fact). A struck metal bar holds its energy far longer than a string.
• Sustain (acoustic fact). A bell decays; it never holds.
• Filter Cutoff (acoustic fact). A bell is bright: its energy sits in high, widely spaced partials rather than in the fundamental, so it takes a far more open filter than an electric piano. Close the filter down and you remove the partials that make it a bell at all.

Organ

How the note speaks (articulation). Everything not listed below is unchanged from the base keys. A preset claims this band by declaring "articulation": "organ" in its tags; until it does, the base band still applies to it.

Stacked octaves, no FM, and a note that holds flat until you let go. An organ has no envelope in the sense the other keys have one: the key is a valve, and the note is simply on or off. Everything below follows from that one fact.

• FM Mode (acoustic fact). Off, and this is the switch rather than the depth. Setting FM Depth to zero leaves the mode on and the modulator running into a depth of nothing, which is not the same as an additive instrument even though it sounds like one. Turn the mode off and the FM rows on this page stop applying at all, which is the honest description of what an organ is.
• FM Depth (acoustic fact). An organ is additive, not FM: it stacks ranks of pipes at octaves and fifths. With the mode off this control is inert, and it is pinned at zero here so that turning the mode back on does not reveal a setting nobody chose.
• Osc3 Level (acoustic fact). Osc 3 is silent by default, and raising it is what turns one pipe into a rank. This is the additive part of the instrument: an organ's tone comes from stacking whole-number intervals above the fundamental rather than from bending one waveform. Below about 20% the upper rank is inaudible and you have a single pipe; past about 60% the rank is louder than what it is meant to reinforce.
• Osc3 Octave (acoustic fact). One octave up, which is the drawbar an organist reaches for first. Whole octaves are what keep the stack harmonic, and that is why the interval matters more than the level: an octave reinforces partials the fundamental already has, so the result is one fuller pipe rather than two notes.
• Sustain (acoustic fact). A pipe sounds for as long as air moves through it, so the note does not decay at all while the key is down.
• Attack (acoustic fact). The pipe takes a moment to speak as the air column starts up.
• Decay (acoustic fact). An organ has no decay stage at all. A pipe or a tonewheel is at full level or it is silent, so there is nothing for the note to fall away to while the key is held. The base keys band starts at 0.25 s because a hammer strikes a string and the string immediately begins to lose energy, and no organ does that. Set the decay as short as it goes: with sustain at or near full, the segment is a no-op anyway, and any longer value is a shape the instrument cannot have.
• ModEnv2 Atk (acoustic fact). The envelope that brings the upper rank in, and the reason it is slow is a real behaviour rather than a taste. On a drawbar organ the upper drawbars settle in a moment after the key goes down, so the rank arrives behind the fundamental instead of with it. Set it instant and the stack sounds like one synthetic waveform. Past about 1.2 s the rank is heard arriving as a separate event, which is a swell rather than an organ.
• ModEnv2 Sus (acoustic fact). Full, so the rank stays in once it has arrived. This envelope is doing one job, which is to delay the entrance; anything less than full and it starts fading the rank back out again while the key is still down, which no organ does.
• Mod Env 2 to Osc3 Level (acoustic fact). What turns the two Osc 3 rows above into the drawbar behaviour rather than a static stack. Mod Env 2's slow attack is applied to the upper rank's level, so it breathes in behind the fundamental. Without this routing the rank is simply present from the first instant and the patch is an additive waveform rather than an instrument with pipes in it.

Synth keys

What the note is made of (timbre). Everything not listed below is unchanged from the base keys. A preset claims this band by declaring "timbre": "synth" in its tags; until it does, the base band still applies to it.

A keyboard sound that is not pretending to be an acoustic instrument. Every other band in this category is bounded by what a hammer, a tine, a reed or a tonewheel physically does, and those bounds are worth trusting precisely because they are facts. They are also the wrong bounds for a patch that never claimed to be a piano. This variant exists to say so out loud rather than to quietly widen the acoustic band and pretend the fact was never a fact. It is a timbre, so it says what the note is made of: a wavetable instead of an FM tine, and a filter allowed to sing.

• FM Mode (production convention). Off by default here, because FM is on the base build to produce a tine, and a synth keyboard is not imitating one. Turning it back on is a legitimate choice rather than a mistake: what the variant removes is the obligation, not the option.
• Osc1 Mode (production convention). The tone now comes from a table rather than from a modulator, which is the actual timbre change this variant is named for. SuperSaw is the other honest answer if the patch wants to be a stacked-saw keyboard, and both are things no acoustic keyboard can be.
• Osc1 WT Pos, when Osc1 Mode is Wavetable (production convention). The whole table is available, which is the point. There is no acoustic instrument setting a ceiling here, so the band is the control's own range and the choice is entirely taste. Compare the base build, where the tone is whatever the FM ratio produces and there is no table position at all.
• Filter Reso (Kiwisynth-specific, our judgment). The base band stops at 20% because a resonant peak colours the attack, and a struck note has to read as struck. That is true and it stays true: this is not a correction of it. It simply does not bind a sound that is not a struck acoustic instrument, where the peak is a voice rather than an artefact. Provenance is our judgment, not a fact: no acoustic keyboard does this, so world knowledge has nothing to say about where the ceiling belongs. Past about 50% the peak sings loudly enough that the sound reads as a filter sweep rather than as a keyboard, which is the practical limit we have found by ear.