Session 24: Texture Sound Design

Objective: Build an evolving noise/texture patch using noise through the VCF with S&H modulation, wave folding for harmonic complexity, and LFO movement for organic, non-pitched sound design.

Sound Design Strategy: Texture

Texture patches occupy a different role than tonal patches. They do not have a clear pitch or rhythm -- instead they provide atmosphere, movement, and space. Think of them as the weather in a mix: wind, rain, rustling, hissing, crackling. Good textures evolve slowly and never quite repeat, giving the listener a sense of organic life beneath the tonal elements.

The building blocks are noise (the raw material), filtering (to shape the noise spectrum), modulation (to create movement), and wave folding (to add harmonic complexity that takes the sound beyond simple filtered noise). S&H and slew-smoothed random voltages are essential for creating movement that never repeats.

Warm-Up (2 min)

Remove all cables. Set all knobs and sliders to noon/center. Play a MIDI note -- you should hear the normalled default tone. Set Mixer NOISE to ~50%, SAW to 0%, and listen to filtered noise. Switch NOISE TYPE through WHITE, PINK, ALT. Return to noon.

Building the Patch

Cables for this patch:

VCO A

• OCTAVE: 4 (for occasional pitched undertone)
• PITCH: noon

Mixer

• NOISE: ~65% (primary source)
• NOISE TYPE: WHITE
• SAW: ~15% (subtle pitched undertone blended with noise)
• All other sliders: 0%

VCF

• FREQ: ~35% (moderate cutoff shapes noise spectrum)
• Q: ~40% (resonance adds tonal character to noise)
• MODE: BP4 (narrow bandpass concentrates the noise)
• LEVEL: ~55%
• FM 1: ~25% (envelope shapes noise on each trigger)
• FM 2: noon
• FM 3: ~35% (S&H random on cutoff -- Cable 1)
• QM: ~30% (LFO modulates resonance -- Cable 3)

Envelope B (filter)

• Attack: ~10%
• Decay: ~50%
• Sustain: ~35%
• Release: ~40%

Envelope A (amplitude)

• Attack: ~15%
• Decay: ~35%
• Sustain: ~65%
• Release: ~45%
• ENVELOPE SPEED: Med
• HOLD POSITION: Off
• CTRL SOURCE: Off

VCA A

• LEVEL: ~35%
• LEVEL MOD: ~50%
• AUX IN: 0%

Wave Folder

• FOLD: ~20% (base fold amount)
• MOD: ~40% (S&H modulates fold depth -- Cable 2)

LFO

• RATE: ~20% (slow modulation)

Utilities — Slew Limiter

• SLEW RATE: ~40%
• SLEW DIRECTION: Both
• SLEW SHAPE: EXP

Output Control

• MAIN DRIVE: noon
• MAIN LEVEL: ~50%

Step-by-step build:

1. Set Mixer NOISE to ~65%, NOISE TYPE to WHITE, SAW to ~15%. Set VCF MODE to BP4, FREQ to ~35%, Q to ~40%. Play and hold a note -- you should hear a concentrated band of noise with a resonant, almost tonal character. The bandpass focuses the noise into a narrow frequency range
2. Set VCF FM 1 to ~25%, Envelope B: Attack ~10%, Decay ~50%, Sustain ~35%, Release ~40%. Play notes -- each trigger sweeps the filter through the noise spectrum, creating a "whoosh" quality on each note
3. Patch Cable 1: S&H OUT -> VCF FM 3 IN. Set FM 3 to ~35%. The filter cutoff now jumps to random positions on each MIDI clock tick (or PUSH GATE press), creating unpredictable spectral changes in the noise

4. Set Wave Folder FOLD to ~20%. The noise gains harmonic complexity -- the wave folder adds overtone patterns to the noise spectrum that would not exist from simple filtering
5. Patch Cable 2: SLEW OUT -> Wave Folder FOLD MOD IN. Set Wave Folder MOD to ~40%. Set Slew RATE to ~40%, SHAPE EXP, DIRECTION Both. Now the fold depth wanders smoothly as the slew-smoothed random voltage changes. The harmonic complexity evolves organically

6. Patch Cable 3: LFO X OUT -> VCF Q MOD IN. Set QM to ~30%, LFO RATE to ~20%. The resonance now pulses slowly -- sometimes the noise has a sharp, ringing quality, sometimes it is broader and flatter. This adds another layer of movement
7. Set Envelope A: Attack ~15%, Decay ~35%, Sustain ~65%, Release ~45%, ENVELOPE SPEED Med. Play and hold -- the texture swells in gently and sustains with continuous movement from the S&H, slew, and LFO modulation

Playing Tips

• Hold notes for 10+ seconds to hear the full evolving character. The S&H and slew create changes that unfold over time
• Play at different pitches -- the pitched sawtooth undertone shifts, subtly coloring the noise texture
• Try NOISE TYPE PINK for a warmer, less hissy texture. Try ALT for digital, metallic noise character
• This patch works well as a background element layered under other instruments

Variations

• Metallic texture: Switch NOISE TYPE to ALT, raise Q to ~55%, and add Mixer IN 1 at ~25% for ring mod metallic content
• Dark rumble: Switch MODE to LP4, lower FREQ to ~20%, lower Q to ~15%, use PINK noise for a deep, dark atmosphere
• Crackle: Use ALT noise with very short Envelope B (Decay ~10%, Sustain ~0%), high FM 3 (~50%). Each clock tick creates a short, random-pitched pop

Output Checklist

• Texture patch built from noise through BP4 filter with resonance
• S&H provides stepped random filter modulation
• Slew-smoothed random modulates wave fold depth for evolving harmonics
• LFO modulates resonance for pulsing spectral character
• Patch documented in patches/cascadia/granular-texture-recipe.md with full cable routing and knob settings
• Session logged in Obsidian daily note

Key Takeaways

• Texture patches use noise as the primary source material, shaped by filtering, modulation, and wave folding into evolving atmospheres
• Splitting the same random source (S&H) into stepped (direct) and smoothed (slewed) versions creates two complementary modulation characters from one source
• Resonance modulation via LFO adds a pulsing, breathing quality that makes textures feel organic rather than static

Next Session Preview

Session 25 is the curriculum capstone: an ambient patch that combines techniques from every module -- slow LFOs, S&H drift, long envelopes, wave folding, and FX integration. You will build the most complex patch in the curriculum.