sbl::widgets::proc::Svf Class Reference

#include <svf.hpp>

Collaboration diagram for sbl::widgets::proc::Svf:

Public Member Functions
void	set_sample_rate (uint32_t sr)
void	set_cutoff (float freq_hz)
	Set cutoff frequency in Hz.
void	set_resonance (float q)
	Set resonance.
void	set_resonance_compensation (float k)
	Set resonance compensation strength.
void	set_mode (FilterMode mode)
	Set filter output mode.
void	process (float *buf, uint16_t frames)
	Process a block of audio samples in-place.
void	process_modulated (float *buf, uint16_t frames, const float *mod, float center, float depth, float lo=20.0f, float hi=20000.0f)
	Process with per-sample exponential cutoff modulation.
void	reset ()
	Reset filter state.

Detailed Description

Definition at line 54 of file svf.hpp.

Member Function Documentation

process()

void sbl::widgets::proc::Svf::process ( float *  buf, uint16_t  frames  )

inline

Process a block of audio samples in-place.

ZDF SVF — unconditionally stable, no oversampling needed.

Parameters

buf	Float audio buffer (modified in-place, [-1.0, 1.0])
frames	Number of samples

Definition at line 112 of file svf.hpp.

References sbl::widgets::proc::BandPass, sbl::widgets::proc::HighPass, sbl::widgets::proc::LowPass, and sbl::widgets::proc::Notch.

process_modulated()

void sbl::widgets::proc::Svf::process_modulated ( float *  buf, uint16_t  frames, const float *  mod, float  center, float  depth, float  lo = 20.0f, float  hi = 20000.0f  )

inline

Process with per-sample exponential cutoff modulation.

Applies exponential modulation to the cutoff frequency per sample, recomputing ZDF coefficients each sample. The modulation signal is normalized [-1, 1] and depth is in octaves — perceptually uniform regardless of the center frequency.

This replaces the manual per-sample loop pattern: for (i = 0; i < n; ++i) { filter.set_cutoff(cutoff + lfo[i]); // WRONG: linear, broken filter.process(&buf[i], 1); }

With: filter.process_modulated(buf, n, lfo, cutoff, 2.0f); // ±2 octaves

Parameters

buf	Float audio buffer (modified in-place)
frames	Number of samples
mod	Modulation signal buffer (normalized [-1.0, 1.0])
center	Center cutoff frequency in Hz
depth	Modulation depth in octaves (e.g., 2.0 = ±2 octaves)
lo	Minimum cutoff in Hz (default 20)
hi	Maximum cutoff in Hz (default 20000)

Definition at line 162 of file svf.hpp.

References sbl::widgets::proc::BandPass, sbl::signal::exp_mod(), sbl::dsp::fast_tan_pif(), sbl::widgets::proc::HighPass, sbl::widgets::proc::LowPass, and sbl::widgets::proc::Notch.

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reset()

void sbl::widgets::proc::Svf::reset ( )

inline

Reset filter state.

Definition at line 208 of file svf.hpp.

set_cutoff()

void sbl::widgets::proc::Svf::set_cutoff ( float  freq_hz )

inline

Set cutoff frequency in Hz.

Parameters

freq_hz

Cutoff in Hz (e.g., 1000.0f)

Definition at line 64 of file svf.hpp.

References sbl::dsp::fast_tan_pif().

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set_mode()

void sbl::widgets::proc::Svf::set_mode ( FilterMode  mode )

inline

Set filter output mode.

Definition at line 102 of file svf.hpp.

set_resonance()

void sbl::widgets::proc::Svf::set_resonance ( float  q )

inline

Set resonance.

Parameters

q	0.0 = no resonance (flat), 1.0 = maximum resonance

Definition at line 75 of file svf.hpp.

set_resonance_compensation()

void sbl::widgets::proc::Svf::set_resonance_compensation ( float  k )

inline

Set resonance compensation strength.

Controls how much the input signal is attenuated as resonance increases: gain = 1 / (1 + q * k). This prevents the resonant peak from clipping during filter sweeps.

k = 0 No compensation (default, backward compatible) k = 2 Gentle drop (~33% volume at full resonance) k = 4 Strong drop (~20% volume at full resonance)

Parameters

k	Compensation amount (0.0 = off)

Definition at line 96 of file svf.hpp.

set_sample_rate()

void sbl::widgets::proc::Svf::set_sample_rate ( uint32_t  sr )

inline

Note

All public methods are ISR-safe — bounded computation, no I/O.

Definition at line 58 of file svf.hpp.

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The documentation for this class was generated from the following file:

• src/sbl/widgets/proc/svf.hpp