Frequency Phaser

A terminal-based multi-oscillator frequency generator.
Schumann resonances, healing tones, brainwave entrainment, chords — all from your keyboard.

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"In theory, if you load a Taylor Swift MP3 and tune the resonance dial to the Schumann frequency, you could drill through stone. We accept no liability for geological incidents."

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Features

Multi-Oscillator Engine

• Up to 8 simultaneous oscillators, each independently tunable
• Per-oscillator frequency (0.01 Hz – 96 kHz), amplitude, waveform, and stereo channel routing (L / R / L+R)
• Lock-free audio thread — no mutexes on the hot path

Waveforms

Symbol	Name	Description
∿	Sine	Pure tone
⊓	Square	Odd harmonics, hollow
⋀	Triangle	Softer odd harmonics
⟋	Sawtooth	Full harmonic series, bright
≋	Pink Noise	1/f broadband noise

Filters

Filter	Description
None	Raw waveform
Orchestral	Additive harmonics + ensemble detuning + 5.5 Hz vibrato + bow noise

Preset Library (67+ presets)

Category	Examples
Schumann	7.83 Hz, 14.3 Hz, 20.8 Hz, 27.3 Hz, 33.8 Hz
Brainwave	Delta (0.5–4 Hz), Theta, Alpha, Beta, Gamma
Solfeggio	174, 285, 396, 417, 528, 639, 741, 852, 963 Hz
Chakra (Traditional)	Root 256 Hz → Crown 963 Hz
Chakra (Vedic)	Root 194.18 Hz → Crown 172.06 Hz
Musical	A432, A444, Concert A440, C256, Middle C
Healing	Tibetan 432, Earth Resonance, Golden Ratio
Geotechnical	Seismic P-wave, S-wave, Rayleigh, Love wave, micro-tremor, soil resonance…
Reference	1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 20 kHz, sub-bass, infrasound

Polyphonic Mode

Layer up to 8 voices as a chord or scale, rooted at any frequency:

• 12 chord types: Power, Major, Minor, Diminished, Augmented, Major 7th, Minor 7th, Dominant 7th, Sus2, Sus4, Add9, Major 9th
• 11 scale types: Major, Natural Minor, Harmonic Minor, Pentatonic Maj/Min, Blues, Dorian, Phrygian, Lydian, Mixolydian, Chromatic
• 3 voicings: Close · Open · Wide
• Preset cycling moves the entire chord in relative frequency — perfect for harmonic exploration

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Controls

Normal Mode

Key	Action
Enter	Play / Stop
← →	Adjust frequency (current step size)
Shift + ← →	Coarse frequency adjust
Page Up / Down	Decade jump (×10 / ÷10)
↑ ↓	Oscillator volume ±5%
+ / -	Master volume ±5%
Tab / Shift+Tab	Cycle active oscillator
W	Next waveform
F	Cycle filter (None → Orchestral → Choir → Drum → Shofar → File)
L	Load WAV/MP3 as custom file filter
S	Cycle step mode (Fine / Medium / Coarse)
E	Enable / disable active oscillator
Y	Enable polyphonic mode + open Poly Panel
P	Preset browser (stopped) / cycle presets (playing)
F1	Add oscillator
F2	Remove active oscillator
0–9 .	Begin direct frequency entry
Q	Quit

Direct Frequency Entry

Start typing any digit or . to enter a frequency in Hz directly. Press Enter to apply, Esc to cancel.

Preset Browser

Key	Action
↑ ↓ / j k	Navigate presets
Enter	Apply preset
Esc / P	Close browser

Poly Panel (Y)

Key	Action
Enter	Play / Stop
← →	Shift root note by semitone
Shift + ← →	Shift root note by octave
↑ ↓	Previous / next chord or scale type
Tab	Toggle Chord ↔ Scale mode
V	Cycle voicing (Close → Open → Wide)
P	Open preset browser (returns to Poly Panel)
Y	Turn polyphony off
Esc	Return to Normal mode (poly stays on)

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Building

# Prerequisites: Rust 1.70+ and a working audio output device

cargo build --release
cargo run --release

Audio is non-fatal — the UI works without a sound card (useful for frequency planning).

Dependencies

• cpal 0.15 — cross-platform audio (WASAPI / CoreAudio / ALSA)
• ratatui 0.29 — terminal UI
• crossterm 0.28 — terminal events
• anyhow 1 — error handling

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Architecture

main.rs
├── audio/
│   ├── engine.rs       # cpal stream setup, audio callback
│   └── generator.rs    # Oscillator, OrchestrialState, PinkNoiseGen, OscillatorRt
├── state.rs            # Lock-free shared state (AtomicU64/U32/Bool)
├── music.rs            # Chord/scale theory, PolyConfig, MIDI ↔ Hz helpers
├── presets.rs          # 67+ frequency presets
└── ui/
    ├── app.rs          # Event handling, InputMode state machine
    └── render.rs       # ratatui layout, circular dial, poly panel, preset sidebar

All oscillator parameters (frequency, amplitude, waveform, filter, channel, enable) are stored as atomics shared between the UI thread and the audio callback — no locking required on the hot path.

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License

GNU General Public License v3.0 — see LICENSE for the full text.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU GPL as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.