Filters that follow your playing
A fixed filter sets the tone. A moving filter brings it to life: it opens with every strike, answers your touch, and keeps its brightness even from the lowest bass note to the top of the keyboard.
- Make a pluck with the filter envelope
- Turn your touch into tone with Touch → brightness
- Keep the brightness even across the keyboard with Key tracking
01How real instruments change their brightness
No acoustic instrument keeps the same tone color all the time. Three habits matter most, and you have heard all of them on a piano for years:
- Bright strike, darker decay. When a hammer hits a string, the upper overtones are strong at first and die away faster than the fundamental. The note gets darker as it fades.
- Harder is brighter. Play the same key harder and it doesn’t just get louder. It gets brighter, because a fast hammer excites more high overtones.
- Every register sounds balanced. A high note on a good piano isn’t dull, and a low note isn’t harsh: the brightness scales with the pitch.
A synth filter does none of this on its own. KiMiA gives you one control for each habit: the filter envelope, Touch → brightness and Key tracking. Together they turn a static synth tone into something that feels played.
02The filter envelope: brightness that moves with the note
Filter 1 has its own filter envelope. It lives in the envelope panel under the filters: click Filter on its row of buttons (Amp, Filter, Mod, Env 4, Env 5) and the panel shows the Edit›Filter envelope with its Attack, Decay, Sustain and Release. It works like the volume envelope you know (Module 7 covers envelopes in depth), but instead of the loudness it moves the cutoff. Envelope amount says how far: at the envelope’s peak, +100% raises the cutoff four octaves, and −100% lowers it four.
A plucked note without and with the filter envelope
This is the whole trick behind synth plucks, keys and many basses: a low cutoff, a positive Envelope amount, and a filter envelope that falls back. With a 300 Hz cutoff and +70%, the strike opens the filter 2.8 octaves, to 2.1 kHz, and the filter envelope brings it home within a few tenths of a second, while the note itself rings on.
For anything struck or plucked, like pianos, guitars, mallets and harps, set both envelopes’ Sustain to 0: a real string gets all its energy at the strike and can only decay. Then make the filter envelope’s decay about half as long as the volume’s. The tone darkens while the note is still sounding, exactly the “bright strike, darker decay” of the piano.
- Negative amounts work the other way round: the filter closes at the strike and opens as the envelope falls. That is useful for unusual swells and “backwards” effects.
- Filter 2 follows the same envelope with its own Envelope amount (Lesson 5.2).
- Want a third shape? The separate Edit›Mod envelope can move either filter’s cutoff on its own timing. You will meet it in Module 7.
03Touch → brightness: your touch becomes tone
Touch → brightness is the single most important control for a keyboard player. It connects how hard you strike each key to how bright that note is, just like the piano habit above. You find it on the Edit›Filter 1 panel, beside Key tracking. Its partner for loudness, Velocity → level, sits on the Amp envelope.
Its value is a number of octaves: how far the cutoff moves over the whole velocity range. The middle of your touch is the anchor. A normal touch plays the Cutoff exactly as you set it; softer notes close the filter below it, harder notes open it above it.
Touch → brightness: your touch becomes tone
So set the Cutoff for your normal playing first, then choose how much the touch should move it: 1 to 2 octaves for a subtle, natural response, 3 octaves for keys that come alive, more for dramatic synth sounds. Now listen to it in a musical phrase, a crescendo on a C major chord:
“Normal touch” depends on your keyboard’s velocity curve, set per keyboard in Routing: Linear, Soft touch, Hard touch or Fixed · 100. KiMiA starts every keyboard on Hard touch, where a velocity of 100 is the normal touch. If your keyboard has a heavy action and you rarely reach high velocities, try Soft touch: it raises lighter playing, so the filter responds without you having to hammer the keys.
04Key tracking: even brightness across the keyboard
In Lesson 5.1 you heard the problem: one fixed cutoff makes low notes bright and high notes dull. Key tracking fixes it by moving the cutoff with the note you play. It sits on the Filter 1 panel, beside Touch → brightness.
Key tracking on the Filter 1 panel
Three octaves, one cutoff: without and with Key tracking
Middle C (C4) is the anchor: there the cutoff is exactly what you set. At 100% the cutoff moves a full octave for every octave you play, so every note keeps the same number of harmonics below it. At 50% it moves half an octave per octave: high notes still open up a little, but less than they would on their own.
| Sound | Key tracking | Why |
|---|---|---|
| Leads, plucks, keys | 50% to 100% | Every note should be clear across the whole range |
| Pads, strings | 30% to 60% | High notes open a little, but the pad stays soft on top |
| Basses | 0% to 40% | Low notes keep their punch without the top notes turning harsh |
| Comb and self-oscillating Ladder | 100% | The filter itself plays the pitch (Module 6) |
| Vowel, fixed formants | 0% | A voice keeps its formants wherever the melody goes |
05All three together
The three tools stack. The filter envelope shapes each note over time, Touch → brightness sets how far each note opens, and Key tracking keeps the registers balanced. Here is a starting point that works for most expressive keys and plucks:
| Control | Where | Starting value |
|---|---|---|
| Cutoff | Edit › Filter 1 | 400 Hz–1.5 kHz (for your normal touch) |
| Envelope amount | Edit › Filter 1 | +40% to +70% |
| Attack · Decay · Sustain | Edit › Filter envelope | 1–5 ms · about half the volume’s decay · 0% for struck sounds |
| Key tracking | Edit › Filter 1 | 50% to 100% |
| Touch → brightness | Edit › Filter 1 | 1.5 to 3 octaves |
| Sustain (struck sounds) | Edit › Amp envelope | 0% |
06Try it
- Make a pluck. Load 05 · Course Init. Set Slope 24 dB and Cutoff 300 Hz. In the Amp envelope set Attack 2 ms, Decay 0.8 s, Sustain 0%, Release 0.5 s. In the Filter envelope set Attack 2 ms, Decay 0.36 s, Sustain 0%. Now raise Envelope amount from 0% to +70% while you play short notes. Listen for the moment it turns from a dull thud into a pluck.
- Add touch. Set Touch → brightness to 3 octaves. Play a scale from very soft to very hard. The last note should be clearly brighter, not just louder.
- Balance the keyboard. Play the same short phrase at C2, C4 and C6. Then set Key tracking to 100% and play it again. Lower it until the top octave is as bright as you like.
- Compare with the reference. Load 05 · Envelope Pluck and 05 · Touch Keys and compare them with your versions.
With your pluck from step 2, play a gentle arpeggio pattern (for example C–G–E–G in eighth notes) and shape the dynamics as you would on a piano: a crescendo over two bars, then a sudden piano. If the brightness follows your hands, you have made an expressive patch.