hysteresis.lib

Hysteresis library. Its official prefix is hy.

This library provides physics-based magnetic hysteresis models for audio processing. Suitable for transformer saturation, tape emulation, and magnetic effects.

Currently implemented models: * Jiles-Atherton (ja_*) - Physics-based ferromagnetic hysteresis

The Hysteresis library is organized into 3 sections:

Musical Character

The c (reversibility) and input calibration work together:

Calibration c Character
-50 dB 0.25 Forward, open, dynamic
0 dB 0.9 Compressed, set back, controlled

Blend between these extremes for different textures.

References

Jiles-Atherton Core

The core hysteresis function implementing the Jiles-Atherton model with 4x cascaded substeps and cubic Hermite interpolation for smooth transients.

(hy.)ja_hysteresis

Jiles-Atherton hysteresis core with 4x substep interpolation. Implements magnetic hysteresis with smooth transient response using cubic Hermite interpolation between samples.

Usage

_ : ja_hysteresis(Ms, a, alpha, k, c) : _

Where:

  • Ms: saturation magnetization, controls maximum output level (100-1000, default 380)
  • a: anhysteretic curve shape parameter (100-2000, default 720)
  • alpha: mean-field coupling coefficient (0.001-0.1, default 0.015)
  • k: coercivity, controls hysteresis loop width (50-1000, default 380)
  • c: reversibility factor, ratio of reversible to irreversible magnetization (0-1, default 0.25)

Test

hy = library("hysteresis.lib");
os = library("oscillators.lib");
ja_hysteresis_test = os.osc(100) * 0.5 : hy.ja_hysteresis(380, 720, 0.015, 380, 0.25);

References

Jiles-Atherton Processors

Ready-to-use processors with gain staging and DC blocking.

(hy.)ja_processor

Complete mono Jiles-Atherton hysteresis processor with drive control, automatic gain compensation, and DC blocking.

Usage

_ : ja_processor(Ms, a, alpha, k, c, drive, trim) : _

Where:

  • Ms: saturation magnetization (100-1000)
  • a: anhysteretic curve shape (100-2000)
  • alpha: mean-field coupling (0.001-0.1)
  • k: coercivity/loop width (50-1000)
  • c: reversibility factor (0-1)
  • drive: input drive in linear gain (use ba.db2linear for dB)
  • trim: output trim in linear gain (use ba.db2linear for dB)

Test

hy = library("hysteresis.lib");
ba = library("basics.lib");
os = library("oscillators.lib");
ja_processor_test = os.osc(100) : hy.ja_processor(380, 720, 0.015, 380, 0.25, ba.db2linear(10), 1);

(hy.)ja_processor_stereo

Stereo Jiles-Atherton hysteresis processor applying identical processing to both channels.

Usage

_,_ : ja_processor_stereo(Ms, a, alpha, k, c, drive, trim) : _,_

Where:

  • Ms: saturation magnetization (100-1000)
  • a: anhysteretic curve shape (100-2000)
  • alpha: mean-field coupling (0.001-0.1)
  • k: coercivity/loop width (50-1000)
  • c: reversibility factor (0-1)
  • drive: input drive in linear gain
  • trim: output trim in linear gain

Test

hy = library("hysteresis.lib");
ba = library("basics.lib");
os = library("oscillators.lib");
ja_processor_stereo_test = os.osc(100), os.osc(150) : hy.ja_processor_stereo(380, 720, 0.015, 380, 0.25, ba.db2linear(10), 1);

Jiles-Atherton UI Wrappers

Ready-to-use processors with built-in user interface controls.

(hy.)ja_processor_ui

Mono Jiles-Atherton hysteresis processor with full UI controls for all parameters. Includes smoothed controls and sensible defaults.

Usage

_ : ja_processor_ui : _

Test

hy = library("hysteresis.lib");
os = library("oscillators.lib");
ja_processor_ui_test = os.osc(100) : hy.ja_processor_ui;

(hy.)ja_processor_stereo_ui

Stereo Jiles-Atherton hysteresis processor with full UI controls. Applies identical processing to both channels with shared parameters.

Usage

_,_ : ja_processor_stereo_ui : _,_

Test

hy = library("hysteresis.lib");
os = library("oscillators.lib");
ja_processor_stereo_ui_test = os.osc(100), os.osc(150) : hy.ja_processor_stereo_ui;