Organic No-Input Mixer — User Guide

Generative analog synthesis: creates evolving, living sounds through pure feedback circuits without external audio input, simulating the behavior of physical no-input mixer systems with organic instability and drift.

Author: Shai Cohen Version: 1.1 (Organic) License: MIT License Category: Generative Synthesis & Analog Simulation

Contents:

What this does Quick start Sound Presets Circuit Physics Spatial Modes Organic Behavior Creative Applications

What this does

This script implements pure generative synthesis — creating complex, evolving sounds from nothing but feedback circuits, simulating the behavior of physical "no-input mixer" setups where mixing console outputs are patched back into their own inputs. The process: (1) Circuit Initialization: Seeds a stereo feedback loop with ultra-low-level Gaussian noise. (2) Parameter Presets: Offers four carefully tuned starting points that create specific sonic characters. (3) Organic Evolution: Runs 60 iterations of filtering and feedback with simulated analog drift and instability. (4) Dynamic Filtering: Applies resonant bandpass filtering with center frequencies and bandwidths that drift randomly each iteration. (5) Spatial Processing: Transforms the raw circuit output through one of four spatialization algorithms. The result is a unique, living soundscape that evolves organically over time.

Key Features:

4 Preset Sound Worlds — Edge of Oscillation, Deep Throbbing Drone, High Frequency Whistle, Degraded Cassette Loop
Pure Generative — No audio input required, creates sound from mathematical feedback
Analog Simulation — Models component drift, instability, and nonlinearities
Organic Evolution — Sounds develop and change over their duration
4 Spatial Modes — Mono, Stereo Wide, Rotating, Binaural spatialization
Parameter Control — Fine-tune feedback gain, damping, resonance, and instability
Deterministic Randomness — Consistent results from same parameters
Self-Organizing — Simple rules create complex emergent behavior

What is "no-input" synthesis? Traditional synthesis: Oscillators, samples, or physical modeling. No-input synthesis: Creating sound purely through feedback loops in audio equipment. Advantages: (1) Organic character: Sounds feel alive and evolving. (2) Unpredictability: Emergent behavior from simple systems. (3) Analog warmth: Simulated component imperfections. (4) Minimalism: Maximum results from minimum elements. (5) Experimental: Exploration of chaos and self-organization. Use cases: Ambient music (evolving drones), sound design (organic textures), installation art (generative soundscapes), meditation (evolving sonic environments), teaching (nonlinear systems demonstration).

Technical Implementation: The script simulates a virtual analog circuit with: (1) Feedback Path: Stereo loop where output feeds back to input. (2) Resonant Filter: Bandpass filter with drifting center frequency and bandwidth. (3) Nonlinearities: arctan() function simulates analog saturation/soft clipping. (4) Damping System: Multiplicative damping prevents infinite gain buildup. (5) Analog Drift: Random variations in filter parameters simulate component instability. Key insight: The system starts from near-silence (Gaussian noise μ=0, σ=0.0001) and through feedback and filtering, self-organizes into complex, musical patterns.

Quick start

In Praat, ensure no objects are selected (script creates everything internally).
Run script… → organic_no_input_mixer.praat.
Choose a Preset (start with "Edge of Oscillation (Subtle)").
Select a Spatial_Mode (start with "Stereo Wide (Freq Split)").
Set Duration_(s) (10.0 seconds is good for testing).
Click OK — watch console messages as circuit initializes and runs.
Output named "Final_Output" appears in Objects window and plays automatically.
Try different presets to explore different sonic worlds.

Quick tip: Start with "Edge of Oscillation (Subtle)" preset — creates delicate, evolving tones. Use 10-30 second durations for testing — longer durations allow more evolution. The Iterations = 60 default creates good complexity — increase to 80-100 for more evolution, decrease to 30-40 for simpler results. Stereo Wide mode works well for headphones or speakers. Listen for how the sound evolves — it starts quietly and builds complexity. Each preset creates a completely different sonic character — explore all four. The script is self-contained — no need to select any audio files first. Processing time increases with duration and iterations — 10 seconds × 60 iterations takes about 15-30 seconds.

Important: NO AUDIO INPUT REQUIRED — This is pure synthesis, not processing of existing audio. Clean workspace recommended — Script clears all objects at start, ensure nothing important is in Praat Objects window. Fixed sample rate — Always uses 44100 Hz, not adjustable. Deterministic but complex — Same parameters produce same output, but behavior is complex. Volume varies by preset — Some presets are quiet, some loud — final normalization to 0.95 peak helps. Evolution takes time — Sounds may start simple and evolve over their duration. Not real-time — Processing happens offline, then playback. Stereo processing — Even Mono mode starts as stereo internally.

Sound Presets

🎛️ Preset 1: Edge of Oscillation (Subtle)

Character: Delicate, evolving, on the verge of stability

Parameters: Feedback=1.01, Damping=0.92, Center=440Hz, Width=300Hz, Instability=0.02

Sonic qualities: Gentle tones, subtle modulation, harmonic richness

Best for: Ambient backgrounds, meditation, subtle sound design

Duration recommendation: 30-60 seconds for full evolution

🔊 Preset 2: Deep Throbbing Drone

Character: Powerful, pulsing, sub-bass focused

Parameters: Feedback=1.4, Damping=0.85, Center=60Hz, Width=40Hz, Instability=0.1

Sonic qualities: Strong low frequencies, rhythmic pulsations, physical presence

Best for: Film sound design, experimental music, subwoofer demonstration

Duration recommendation: 10-20 seconds (intense, can be overwhelming)

🎵 Preset 3: High Frequency Whistle

Character: Clear, piercing, sine-like with subtle noise

Parameters: Feedback=1.1, Damping=0.98, Center=2500Hz, Width=50Hz, Instability=0.01

Sonic qualities: Pure tones, high frequency focus, minimal noise

Best for: Testing high-frequency response, ethereal textures, scientific demonstration

Duration recommendation: 5-15 seconds (can be fatiguing at high volumes)

📼 Preset 4: Degraded Cassette Loop

Character: Lo-fi, degraded, noisy with pitch instability

Parameters: Feedback=0.98, Damping=0.99, Center=800Hz, Width=1000Hz, Instability=0.2

Sonic qualities: Tape hiss, wow and flutter, degraded fidelity, nostalgic

Best for: Lo-fi music, retro sound design, nostalgic atmospheres

Duration recommendation: 15-30 seconds (evolves through degradation stages)

Preset Selection Guide

Desired Sound	Recommended Preset	Key Characteristics	Listening Context
Gentle ambient	Edge of Oscillation	Subtle, evolving, harmonic	Headphones, quiet room
Powerful low-end	Deep Throbbing Drone	Physical, pulsing, sub-bass	Good speakers/subwoofer
Clear high tones	High Frequency Whistle	Pure, piercing, minimal	Frequency response testing
Lo-fi texture	Degraded Cassette Loop	Noisy, unstable, nostalgic	Lo-fi production, retro
Custom exploration	Custom	Full parameter control	Experimental sound design

Preset Parameter Analysis

EDGE OF OSCILLATION ANALYSIS: Feedback (1.01): Just above unity → slow buildup Damping (0.92): Moderate decay → sustained but not infinite Center (440 Hz): Concert A → musical reference point Width (300 Hz): Broad resonance → rich harmonics Instability (0.02): Minimal drift → stable evolution DEEP THROBBING DRONE ANALYSIS: Feedback (1.4): Strong positive feedback → rapid growth Damping (0.85): Significant decay → creates pulsation Center (60 Hz): Sub-bass region → physical vibration Width (40 Hz): Narrow resonance → focused frequency Instability (0.1): Moderate drift → organic variation HIGH FREQUENCY WHISTLE ANALYSIS: Feedback (1.1): Gentle feedback → controlled growth Damping (0.98): Minimal decay → sustained tones Center (2500 Hz): High midrange → piercing quality Width (50 Hz): Very narrow → pure sine-like Instability (0.01): Almost stable → consistent pitch DEGRADED CASSETTE LOOP ANALYSIS: Feedback (0.98): Slightly below unity → slow decay Damping (0.99): Almost no decay → very sustained Center (800 Hz): Midrange focus → tape-like Width (1000 Hz): Very wide → noisy, full spectrum Instability (0.2): High drift → significant wow/flutter

Circuit Physics

🔧 Virtual Analog Circuit Components

Feedback Loop: Output continuously feeds back to input

Resonant Filter: Bandpass emphasizing specific frequencies

Nonlinearity: arctan() function simulates analog saturation

Damping: Multiplicative attenuation prevents infinite gain

Noise Seed: Ultra-quiet Gaussian noise initiates process

The Core Feedback Equation

MAIN PROCESSING FORMULA (per sample, per channel): loop[t] = (2/π) × arctan( (loop[t-1] × damping_Factor) + (filtered[t] × feedback_Gain) ) Where: • loop[t-1] = previous sample in feedback loop • damping_Factor = 0.94 (default), prevents infinite gain buildup • filtered[t] = bandpass filtered version of loop[t-1] • feedback_Gain = 1.05 (default), amplification in feedback path • arctan() = soft clipping function, simulates analog saturation PHYSICAL INTERPRETATION: This models: Previous signal × Damping + Filtered signal × Gain → Saturator The arctan() creates soft clipping as signals approach large values Creates complex interplay between amplification and attenuation

Filter Stage with Drift

FILTER PARAMETERS (calculated each iteration): drift_hz = resonance_Center × analog_Instability current_freq = resonance_Center + randomGauss(0, drift_hz) width_drift = resonance_Width × analog_Instability current_width = resonance_Width + randomGauss(0, width_drift) Safety clamping: if current_width < 10: current_width = 10 if current_freq < 20: current_freq = 20 FILTER IMPLEMENTATION: Filter (pass Hann band): current_freq - (current_width/2), current_freq + (current_width/2), 20 Where: • Hann window = smooth frequency response • 20 = filter steepness (higher = sharper cutoff) • Creates resonant peak at current_freq • Bandwidth = current_width EFFECT OF DRIFT: • Each iteration, filter parameters drift randomly • analog_Instability controls drift amount • Creates "living" sound with subtle variations • Simulates analog component temperature drift

Parameter Interactions

Parameter Pair	Interaction	Sonic Result	Stability Region
Feedback_Gain × Damping_Factor	Gain vs decay balance	Feedback_Gain > 1/Damping: grows Feedback_Gain < 1/Damping: decays	Feedback × Damping ≈ 1.0
Resonance_Center × Resonance_Width	Frequency focus vs bandwidth	Narrow width: pure tones Wide width: noisy textures	Width < Center/2 for clarity
Feedback_Gain × Analog_Instability	Growth vs variation	High both: chaotic evolution Low both: stable tones	Instability < 0.5 for control
Iterations × Duration	Evolution time vs density	More iterations: more complex Longer duration: slower change	Iterations ≥ Duration × 4

Circuit Stability Analysis

STABILITY CRITERION: The system is stable if: feedback_Gain × damping_Factor < 1.57 Why 1.57? Because arctan(1) = π/4 ≈ 0.785, and the feedback loop includes 2/π factor. PRACTICAL STABILITY RANGES: Stable (tones, drones): feedback_Gain × damping_Factor = 0.9 - 1.2 Unstable (growing, chaotic): feedback_Gain × damping_Factor = 1.2 - 1.5 Explosive (clips quickly): feedback_Gain × damping_Factor > 1.5 EXAMPLE CALCULATIONS: Preset 1: 1.01 × 0.92 = 0.93 → Stable, subtle Preset 2: 1.4 × 0.85 = 1.19 → Borderline, pulsating Preset 3: 1.1 × 0.98 = 1.08 → Stable, sustained Preset 4: 0.98 × 0.99 = 0.97 → Stable, decaying

Spatial Processing Modes

🎧 4 Spatialization Algorithms

Mono (Summed): Collapses to single channel (compatibility)

Stereo Wide (Freq Split): Frequency-based channel separation (immersive)

Rotating (Auto-Pan): Amplitude panning with rotation (motion)

Binaural (Delay/Filter): Simplified head-related processing (3D)

Mode 1: Mono (Summed)

PROCESS: Convert to mono (average of channels) IMPLEMENTATION: Praat's "Convert to mono" CHARACTERISTICS: • Centered, focused sound image • No stereo width or spatial information • Maximum compatibility with mono systems • Loss of stereo complexity and imaging USE CASES: • Mono playback systems (telephone, cheap speakers) • Further mono processing • When stereo imaging is not important • Compatibility testing TECHNICAL DETAILS: • Averages left and right channels: mono = (L + R) / 2 • Reduces file size (half the channels) • May increase perceived loudness (phase summing)

Mode 2: Stereo Wide (Freq Split)

PROCESS: Frequency-based channel separation Left channel processing: Filter (pass Hann band): 0, 4000, 100 • Passes 0-4000 Hz (low to mid frequencies) • Steepness 100 = sharp cutoff • Result: Warm, bassy left channel Right channel processing: Filter (pass Hann band): 200, 22050, 100 • Passes 200-22050 Hz (mid to high frequencies) • High-pass at 200 Hz removes extreme lows • Result: Bright, detailed right channel CHARACTERISTICS: • Creates wide stereo image through frequency separation • Left = warm/bassy, Right = bright/detailed • Excellent for headphone listening • May sound unnatural on some speaker setups USE CASES: • Headphone listening (maximum width) • Creating immersive soundscapes • When maximum stereo separation desired • Experimental stereo imaging

Mode 3: Rotating (Auto-Pan)

PROCESS: Amplitude modulation with 90° phase difference Left channel formula: L' = L × (0.6 + cos(2π × rotation_rate × time) × 0.4) Right channel formula: R' = R × (0.6 + sin(2π × rotation_rate × time) × 0.4) Where: • rotation_rate = 0.2 Hz (completes cycle every 5 seconds) • 0.6 = center level (prevents complete silencing) • 0.4 = modulation depth (amount of panning) • cos/sin with 90° phase difference creates circular rotation CHARACTERISTICS: • Creates slow, circular panning motion • Sound appears to rotate around listener • Not true 3D, but effective stereo motion • Creates hypnotic, evolving spatial quality USE CASES: • Creating sense of motion without true 3D • Hypnotic, meditative listening experiences • Avoiding static stereo placement • Installation art with speaker arrays

Mode 4: Binaural (Delay/Filter)

PROCESS: Simplified binaural simulation Left channel processing: Filter (pass Hann band): 50, 3000, 80 • Simulates head shadow effect (low-mid frequencies) • 50-3000 Hz passband approximates frontal perception Right channel processing: 1. Apply 30-sample delay: "if col > 30 then self[col-30] else 0 fi" 2. Filter (pass Hann band): 200, 6000, 80 3. Simulates ITD (Interaural Time Difference) and HRTF Where: • 30 samples ≈ 0.68 ms delay at 44100 Hz (simulates sound from right) • Different filter responses simulate head-related transfer functions CHARACTERISTICS: • Creates 3D spatial impression (best with headphones) • Sounds appear to come from around the listener • Simplified but effective binaural simulation • May sound odd on speakers (phase issues) USE CASES: • Headphone-only listening experiences • Creating 3D audio environments • Virtual reality audio preparation • Spatial audio experiments

Spatial Mode Selection Matrix

Listening Context	Recommended Mode	Alternative	Avoid	Reason
Headphones	Binaural	Stereo Wide	Mono	Maximum spatial effect
Stereo speakers	Stereo Wide	Rotating	Binaural	Good width, no phase issues
Mono system	Mono	n/a	All stereo	Compatibility
Ambient installation	Rotating	Stereo Wide	Binaural	Creates sense of motion
Film/TV broadcast	Stereo Wide	Mono	Binaural	Standard compatibility

Organic Behavior

🌱 What Makes It "Organic"

Analog Drift: Parameters change slightly each iteration (temperature drift simulation)

Emergent Complexity: Simple rules create complex, unpredictable results

Self-Organization: Noise evolves into structured patterns

Nonlinear Evolution: Small changes can create dramatically different outcomes

Living Quality: Sounds feel alive, breathing, evolving

The Evolution Process

ITERATION TIMELINE (60 iterations default): Iterations 1-10: INITIALIZATION • Ultra-quiet noise (μ=0, σ=0.0001) • Filter begins to emphasize resonant frequencies • First signs of pattern formation • Sound: Very quiet, barely audible Iterations 11-30: PATTERN FORMATION • Feedback builds specific frequencies • Distinct tonal qualities emerge • Rhythm and pulsation may appear • Sound: Clearly audible, defining character Iterations 31-50: COMPLEXIFICATION • Multiple frequency interactions • Harmonic relationships develop • Spatial characteristics solidify • Sound: Rich, complex, evolving Iterations 51-60: STABILIZATION • System approaches equilibrium • Patterns become consistent • Final character established • Sound: Mature, stable version EFFECT OF DURATION: • Shorter durations: Hear evolution more clearly • Longer durations: Experience stable periods • Very long: May hear cyclical patterns

Analog Instability Simulation

INSTABILITY MECHANISMS: 1. FREQUENCY DRIFT: drift_hz = resonance_Center × analog_Instability current_freq = resonance_Center + randomGauss(0, drift_hz) Example (Center=440Hz, Instability=0.05): drift_hz = 440 × 0.05 = 22 Hz current_freq varies ±22 Hz each iteration Simulates oscillator temperature drift 2. BANDWIDTH DRIFT: width_drift = resonance_Width × analog_Instability current_width = resonance_Width + randomGauss(0, width_drift) Example (Width=100Hz, Instability=0.05): width_drift = 100 × 0.05 = 5 Hz current_width varies ±5 Hz each iteration Simulates filter component tolerance PHYSICAL ANALOGIES: • analog_Instability = 0.01: High-quality studio gear • analog_Instability = 0.05: Typical analog synthesizer • analog_Instability = 0.10: Vintage/aged equipment • analog_Instability = 0.20: Broken/unstable gear

Emergent Patterns

Pattern Type	Causing Parameters	Description	Preset Example
Steady Drone	Feedback≈1.0, Damping≈0.99	Constant tone with subtle variation	Edge of Oscillation
Rhythmic Pulsation	Feedback>1.2, Damping<0.9	Regular amplitude modulation	Deep Throbbing Drone
Frequency Beating	Narrow Width, High Instability	Two close frequencies create beats	High Frequency Whistle
Noise Bursts	Wide Width, Moderate Feedback	Sudden eruptions of noise	Degraded Cassette Loop
Chaotic Evolution	High Feedback, High Instability	Unpredictable, ever-changing	Custom exploration

Listening for Organic Qualities

Signs of "Living" Sound:

Micro-variations: Tiny pitch/flutter changes (not perfect digital stability)
Breathing quality: Subtle amplitude swells and decays
Emergent rhythms: Patterns that weren't explicitly programmed
Non-repetitive: Doesn't sound like a perfect loop
Complex harmonics: Rich overtone structure that evolves
Spatial motion: Sound seems to move/changeposition

Contrast with Digital Synthesis:

Aspect	Digital Synthesis	Organic No-Input
Stability	Perfect, consistent	Drifts, varies
Predictability	Exactly repeatable	Emergent, complex
Purity	Clean, noise-free	Imperfect, noisy
Control	Precise parameter control	Parameter ranges influence
Character	Digital, precise	Analog, warm

Creative Applications

Ambient Music and Soundscapes

🌌 Evolving Ambient Backgrounds

Goal: Create endless, evolving soundscapes for meditation, focus, or background

Workflow:

Use "Edge of Oscillation" preset with Duration=300s (5 minutes)
Set Spatial_Mode to "Stereo Wide" or "Rotating"
Process and record output
Optionally layer multiple instances at different pitches
Use as continuous ambient background

Variations: Create day-long versions for installation, different presets for different moods

Sound Design for Film/Games

🎬 Sci-Fi and Horror Sound Design

Goal: Create otherworldly, unsettling, or futuristic sounds

Workflow:

Use "Deep Throbbing Drone" for ominous backgrounds
Use "High Frequency Whistle" for tension/alert sounds
Use "Degraded Cassette Loop" for retro-tech sounds
Process multiple variations with different parameters
Layer and edit in DAW for final sounds

Examples: Spaceship hum, alien communication, haunted machinery

Generative Art Installations

🏛️ Living Sound Installations

Goal: Create sound that evolves over hours/days in physical space

Workflow:

Create very long durations (1-8 hours)
Use "Rotating" spatial mode for speaker arrays
Set up continuous playback system
Allow sound to evolve naturally over time
Visitors experience different states at different times

Installation ideas: Gallery soundscapes, architectural sound, public space ambient

Advanced Creative Techniques

Multi-Layer Composition:

Generate multiple sounds with different presets/parameters
Layer them in timeline (different start times, durations)
Apply different spatial modes to different layers
Create evolving piece with changing character
Example: Start with Edge, add Drone, transition to Cassette

Parameter Automation:

Create sequence of parameter changes
Process short segments with different parameters
Concatenate results
Creates piece that evolves through parameter space
Example: Gradually increase Instability over 5 minutes

External Processing:

Export sounds for further processing in DAW
Add effects (reverb, delay, modulation)
Time-stretch for different evolution rates
Pitch-shift for different frequency ranges
Granular processing for texture

Troubleshooting Common Issues

Problem: Output is silent or extremely quiet
Causes: Feedback_Gain too low, Damping_Factor too high, insufficient iterations
Solutions: Increase Feedback_Gain (1.05-1.2), decrease Damping_Factor (0.85-0.92), increase Iterations (80-100)

Problem: Sound clips/distorts unpleasantly
Causes: Feedback_Gain too high, insufficient damping, analog_Instability too high
Solutions: Decrease Feedback_Gain (0.95-1.0), increase Damping_Factor (0.95-0.99), decrease analog_Instability (0.01-0.03)

Problem: Sound is static/boring
Causes: analog_Instability too low, iterations too low, duration too short
Solutions: Increase analog_Instability (0.1-0.2), increase Iterations (80-120), increase Duration (30-60s)

Problem: Processing takes too long
Causes: Long duration, high iterations, complex spatial mode
Solutions: Decrease Duration (5-15s), decrease Iterations (30-40), use simpler Spatial_Mode (Mono)

Performance and Quality Guidelines

Quality Level	Duration	Iterations	Spatial Mode	Processing Time
Quick test	5s	30	Mono	5-10 seconds
Standard	10-20s	60	Stereo Wide	15-30 seconds
High quality	30-60s	80-100	Rotating/Binaural	1-3 minutes
Installation	300s+	100-150	Stereo Wide	5-15 minutes