Module 6 · Lesson 5 of 5

Filter FM and choosing a flavor

One last trick: let oscillator 2 move the cutoff hundreds of times a second, and the filter growls. Then a map of all nineteen types, so you can reach for the right one in seconds.

15 minHeadphones or studio monitorsKiMiA and your keyboard

In this lesson you will

Let oscillator 2 play the cutoff
Pick the right filter for a sound in a few seconds
Check your understanding of the whole module

01Filter FM: oscillator 2 plays the cutoff

A modulator moving the cutoff a few times a second makes a wah or a sweep. Move it hundreds of times a second, at the speed of a note, and something new happens: the filter opens and closes inside every cycle of the wave, and the sound gains a growl. That is filter FM.

On the Filter 1 panel, Osc 2 FM, beside Envelope amount, lets oscillator 2 swing the cutoff up and down, up to ±4 octaves. It works on every type but the Comb, the Vowel and the Resonator, whose Cutoff is a pitch, a vowel or a chord; there it is dimmed. Oscillator 2 still plays through the Blend as usual; for filter FM alone, set the Oscillator blend fully to Osc 1, so you hear oscillator 2 only through the filter:

Figure 6.5.1

Oscillator 2 plays the cutoff

Osc 2 FM offOsc 2 FM 35% (±1.4 octaves)

Waveform · C2

Harmonics

Switch while it plays: same moment, different sound Audio example — listen in the online course

Same saw, same 600 Hz low-pass. With Osc 2 FM, oscillator 2 swings the cutoff up and down once per cycle, hundreds of times a second. The filter opens in short bursts, and harmonics far above the cutoff come back: between 1.2 and 6 kHz the strongest is 24 dB louder. With Osc 2 following the keys (the default) the growl stays in tune with the note; switched off, Osc 2 stays at one pitch and the growl turns metallic.

Because oscillator 2 normally follows the keys, the growl stays in tune with every note. Switch off Osc 2 follows the keys on the oscillator panel and oscillator 2 holds one pitch: the growl then clashes with the note and turns metallic, a sound for effects and drones rather than melodies.

Osc 2 FM	You hear
Off to ±0.4 oct	A little more edge and buzz
±0.8 to ±1.6 oct	A clear growl: basses and leads
Above ±2 oct	Harsh and clangy; use it with care

Pro tip

Change oscillator 2’s tuning and the growl changes color: an octave up is smoother, a fifth up rougher. Try a sine on oscillator 2 first; a saw there makes the growl buzz.

02Choosing a flavor

Nineteen types are a lot to remember. Before any map, listen: here is one riff through every one of them.

Figure 6.5.2

Nineteen filters, one riff

06 · Flavor Riff · Cutoff 800 Hz · Resonance 60% · the same envelope

Switch while it plays: same moment, different sound Audio example — listen in the online course

The same two saws, the same riff, the same Cutoff, Resonance and filter envelope: only the Type changes, as when you click through the Type row while you play. The colors group related filters. The loudness differences are real: a high-pass or a band-pass at 800 Hz takes away most of the saws’ energy, which sits low. Load 06 · Flavor Riff and do the same in KiMiA: the ones that surprise you are the ones to remember.

A riff shows how a filter colors music. A sweep shows its character: how it opens, how its resonance sings on the way, where it gets thin or loud. Here is the same sweep through all nineteen, so you can hear each one move.

Figure 6.5.3

Nineteen filters, one sweep

A saw fifth on C3 · Cutoff 80 Hz → 12 kHz → 80 Hz · Resonance 60%

Switch while it plays: same moment, different sound Audio example — listen in the online course

The move every filter is judged by: the Cutoff swept from 80 Hz to 12 kHz and back over six seconds, with Resonance at 60% and no envelope. Listen for how each one opens (smooth or vocal, thin or fat), how its resonance sounds on the way up, and where it gets loud or quiet. The Comb, the Vowel and the Resonator treat the Cutoff as a pitch, a vowel or a chord, so their sweep is a glide through pitches and vowels; the low-pass gate closes its level with its cutoff, so it is nearly silent at the bottom.

You don’t have to remember them all. Start from the sound you want and let this map point you to two or three types to try.

You want	Try first	Then
A clean tone, nothing added	LP, HP, BP, Notch (Module 5)	Morph, Multimode
A fat mono bass or lead	Ladder	Steiner, Diode
An acid squelch	Diode	Ladder
A smooth poly pad or brass	IR3109, SSM2040	Poly, CEM3320
Chords that cut through	CEM3320	IR3109
A screaming, snarling lead	MS-20 LP with Drive	Steiner
A filter that moves on its own	Morph with a modulator	Multimode, Steiner
A woody, natural pluck	Low-pass gate	Comb
A plucked string from noise	Comb	Resonator
A voice, a choir, talking	Vowel	Two band-passes in parallel (Lesson 5.3)
A chord from one note, bells	Resonator	Comb
A growl	Any low-pass with Osc 2 FM	Ladder, MS-20 LP

At the keyboard

When a sound is almost right but not quite, keep everything and click through three or four neighbors on the Type row while you play. Cutoff, Resonance and the envelope stay where they are, so you compare only the filter. It takes ten seconds and often finds the sound.

03Try it

Find the growl. Load 06 · Filter FM Growl and play a bass line. Move Osc 2 FM from Off to ±3 oct and back. Where does it stop being musical for you?
Out of tune on purpose. In the same sound, switch off Osc 2 follows the keys and play again. Then switch it back on and set oscillator 2 an octave up.
Swap the filter. Keep Osc 2 FM at ±1.4 oct and click through LP, Ladder, MS-20 LP and Diode. Which growls best?
Build from the map. Load 06 · Course Init and make a sound for your next gig using the map above: pick the sound, try the two suggested types, keep the better one.

Your notes · the sound you built and the type you chose

04Cheat sheet

Type	In the Slope row’s place	Character	Best for
Ladder	Slope	Warm, thick, sings; slims as resonance rises	Mono basses and leads
Diode	dimmed	Sharp, rubbery peak	Acid lines
Poly	Slope	Smooth, compresses when pushed	Pads, chords
IR3109 · SSM2040 · CEM3320	Slope	The polysynth chips: steady · fat · clean	Brass, pads, chords
MS-20 LP · HP	dimmed	Clipped resonance that snarls	Screaming leads
Steiner	Mode	Low to band to high; hard-clipping resonance	Biting basses
Morph	Morph	Low-pass, notch and high-pass on one knob	Moving pads
Multimode	Mode	Fifteen modes, 6 to 24 dB, notch, phase	Exact slopes, sweeps
Low-pass gate	dimmed	Tone and level close together, slowly	Woody plucks, percussion
Comb	dimmed (Damping beside Resonance)	Rings at the Cutoff’s note	Strings from noise, metallic color
Vowel	Voice type	Five formants: A, E, I, O, U	Talking leads, choirs
Resonator	Spread	Four tuned bands: a chord	Bells, glassy textures
All but Comb, Vowel, Resonator	Osc 2 FM, beside Envelope amount	Oscillator 2 swings the cutoff at audio rate	Growls

05Module check

Q1What does Osc 2 FM do?

The cutoff moves once per cycle of oscillator 2, hundreds of times a second. The filter opens in bursts and harmonics far above the cutoff come back.

Q2A filter-FM bass sounds metallic and out of tune. What is the likely cause?

With oscillator 2 at one fixed pitch, the cutoff’s wobble no longer matches the note, and the growl clashes with it.

Q3Which type would you reach for first for a plucked string made from a burst of noise?

The Comb rings at the Cutoff’s note, and Key tracking 100% moves that note with the keys.

Q4Which type needs no amplitude envelope decay to make a note die away?

The low-pass gate closes the level with the tone. Struck open by the filter envelope, it makes the decay itself.

Q5On which type does the Slope row show Voice type?

The Vowel has no slope; in its place you choose the singer: Soprano, Alto, Tenor or Bass.

06What’s next

You now know every filter in KiMiA and when to reach for each. The filter envelope has opened and closed them all through this module; in Module 7 · Envelopes you will meet all five of KiMiA’s envelopes in depth: their delay, hold and second decay, their curves, and how your playing changes them.