A state-variable filter (SVF) implementation, supporting multiple filter types (12/24 dB, shelving, dual modes). More...

#include <digital_svf.h>

Inheritance diagram for vital::DigitalSvf:

Classes
struct	FilterValues
	Stores three filter state variables (v0, v1, v2) used for multi-mode mixing. More...

Public Types
typedef OneDimLookup< computeSvfOnePoleFilterCoefficient, 2048 >	SvfCoefficientLookup
	A lookup table type for quickly converting frequency ratios into filter coefficients.

Public Types inherited from vital::SynthFilter
enum	{ kAudio , kReset , kMidiCutoff , kResonance , kDriveGain , kGain , kStyle , kPassBlend , kInterpolateX , kInterpolateY , kTranspose , kSpread , kNumInputs }

enum	Style { k12Db , k24Db , kNotchPassSwap , kDualNotchBand , kBandPeakNotch , kShelving , kNumStyles }
	Different filter styles used in various derived classes. More...

typedef OneDimLookup< computeOnePoleFilterCoefficient, 2048 >	CoefficientLookup
	A lookup table for quick computation of one-pole filter coefficients.

Public Member Functions
	DigitalSvf ()
	Constructor that initializes the filter’s internal states.

virtual	~DigitalSvf ()
	Default destructor.

virtual Processor *	clone () const override
	Creates a clone of this filter by invoking the copy constructor.

virtual void	process (int num_samples) override
	Processes a block of samples by pulling from the primary audio input and computing the SVF output. Delegates to `processWithInput()`.

void	processWithInput (const poly_float *audio_in, int num_samples) override
	Processes a block of samples using a provided input buffer.

void	reset (poly_mask reset_masks) override
	Resets internal filter states for voices specified by the `reset_masks`.

void	hardReset () override
	Performs a complete reset of the filter states for all voices.

void	setupFilter (const FilterState &filter_state) override
	Configures this SVF based on a FilterState (cutoff, resonance, style, etc.).

void	setResonanceBounds (mono_float min, mono_float max)
	Sets the minimum and maximum resonance for the filter (used in resonance interpolation).

void	process12 (const poly_float *audio_in, int num_samples, poly_float current_resonance, poly_float current_drive, poly_float current_post_multiply, FilterValues &blends)
	Processes a 12 dB filter style, iterating through the block.

void	processBasic12 (const poly_float *audio_in, int num_samples, poly_float current_resonance, poly_float current_drive, poly_float current_post_multiply, FilterValues &blends)
	Processes a simpler 12 dB filter style, skipping extra color or overshoot logic.

void	process24 (const poly_float *audio_in, int num_samples, poly_float current_resonance, poly_float current_drive, poly_float current_post_multiply, FilterValues &blends)
	Processes a 24 dB filter style, adding additional stages.

void	processBasic24 (const poly_float *audio_in, int num_samples, poly_float current_resonance, poly_float current_drive, poly_float current_post_multiply, FilterValues &blends)
	Processes a simpler 24 dB filter style, skipping advanced processing.

void	processDual (const poly_float *audio_in, int num_samples, poly_float current_resonance, poly_float current_drive, poly_float current_post_multiply, FilterValues &blends1, FilterValues &blends2)
	Processes a dual filter mode, e.g., dual notch + band pass.

force_inline poly_float	tick (poly_float audio_in, poly_float coefficient, poly_float resonance, poly_float drive, FilterValues &blends)
	Applies advanced distortion to the input while performing a single SVF tick (12 dB).

force_inline poly_float	tickBasic (poly_float audio_in, poly_float coefficient, poly_float resonance, poly_float drive, FilterValues &blends)
	A basic (non-distorting) single SVF tick for a 12 dB filter style.

force_inline poly_float	tick24 (poly_float audio_in, poly_float coefficient, poly_float resonance, poly_float drive, FilterValues &blends)
	Tick function for a 24 dB multi-stage filter, adding an additional pre-stage.

force_inline poly_float	tickBasic24 (poly_float audio_in, poly_float coefficient, poly_float resonance, poly_float drive, FilterValues &blends)
	A simpler 24 dB tick function without advanced distortion or color.

force_inline poly_float	tickDual (poly_float audio_in, poly_float coefficient, poly_float resonance, poly_float drive, FilterValues &blends1, FilterValues &blends2)
	Tick function for a dual filter approach, e.g. notch + band, etc.

poly_float	getDrive () const
	Retrieves the final drive (post drive compensation) used in the filter.

poly_float	getMidiCutoff () const
	Retrieves the current MIDI-based cutoff frequency.

poly_float	getResonance () const
	Retrieves the current resonance value (inverted if needed).

poly_float	getLowAmount () const
	Retrieves the current low-frequency mix portion.

poly_float	getBandAmount () const
	Retrieves the current band-frequency mix portion.

poly_float	getHighAmount () const
	Retrieves the current high-frequency mix portion.

poly_float	getLowAmount24 (int style) const
	Helper for a 24 dB filter style that may swap low/high in a dual notch band.

poly_float	getHighAmount24 (int style) const
	Helper for a 24 dB filter style that may swap low/high in a dual notch band.

void	setBasic (bool basic)
	Sets whether this filter should use a simpler, “basic” processing path.

void	setDriveCompensation (bool drive_compensation)
	Enables or disables drive compensation (reducing drive as resonance increases).

Public Member Functions inherited from vital::Processor
	Processor (int num_inputs, int num_outputs, bool control_rate=false, int max_oversample=1)
	Constructs a Processor with a given number of inputs/outputs and oversampling.

virtual	~Processor ()
	Virtual destructor.

virtual bool	hasState () const
	Indicates whether this Processor requires per-voice state.

virtual void	init ()
	Called after constructor, used for any additional initialization. Subclasses can override. Sets the initialized flag.

bool	initialized ()
	Returns whether this Processor has been initialized.

virtual void	setSampleRate (int sample_rate)
	Updates the sample rate of this Processor (scaled by oversampling).

virtual void	setOversampleAmount (int oversample)
	Sets the oversampling amount and updates the effective sample rate.

force_inline bool	enabled () const
	Checks if this Processor is enabled.

virtual void	enable (bool enable)
	Enables or disables this Processor.

force_inline int	getSampleRate () const
	Retrieves the current (effective) sample rate.

force_inline int	getOversampleAmount () const
	Retrieves the current oversampling factor.

force_inline bool	isControlRate () const
	Checks if this Processor is running at control rate (buffer_size == 1).

virtual void	setControlRate (bool control_rate)
	Sets whether this Processor runs at control rate.

force_inline poly_mask	getResetMask (int input_index) const
	Retrieves a mask indicating which voices triggered a note-on event. Compares the input's trigger_value to kVoiceOn.

force_inline void	clearOutputBufferForReset (poly_mask reset_mask, int input_index, int output_index) const
	Clears output samples for voices that are about to be reset, based on the trigger offset.

bool	inputMatchesBufferSize (int input=0)
	Checks whether the buffer size of a particular input matches the size needed by this Processor.

bool	checkInputAndOutputSize (int num_samples)
	Checks if all inputs and outputs have buffers big enough for `num_samples`.

virtual bool	isPolyphonic () const
	Checks if this Processor is polyphonic by querying its ProcessorRouter.

void	plug (const Output *source)
	Connects an external Output to this Processor's first input.

void	plug (const Output *source, unsigned int input_index)
	Connects an external Output to a specified input index.

void	plug (const Processor *source)
	Connects the first output of a Processor to this Processor's first input.

void	plug (const Processor *source, unsigned int input_index)
	Connects the first output of a Processor to a specified input index.

void	plugNext (const Output *source)
	Connects an external Output to the first available (unplugged) input.

void	plugNext (const Processor *source)
	Connects the first output of a Processor to the first available (unplugged) input.

void	useInput (Input *input)
	Uses an existing Input object as this Processor's first input.

void	useInput (Input *input, int index)
	Uses an existing Input object at a specified input index.

void	useOutput (Output *output)
	Uses an existing Output object as this Processor's first output.

void	useOutput (Output *output, int index)
	Uses an existing Output object at a specified output index.

int	connectedInputs ()
	Counts how many inputs are connected to a real source (not null_source_).

virtual void	unplugIndex (unsigned int input_index)
	Removes the connection at a specified input index, if any.

virtual void	unplug (const Output *source)
	Removes a connection to a given Output from all inputs.

virtual void	unplug (const Processor *source)
	Removes connections to all outputs from a given Processor.

virtual void	numInputsChanged ()
	Called when the number of inputs changes (e.g., new connections). Subclasses may override for dynamic behavior.

force_inline void	router (ProcessorRouter *router)
	Sets the ProcessorRouter that owns or manages this Processor.

force_inline ProcessorRouter *	router () const
	Returns the ProcessorRouter that currently owns this Processor.

ProcessorRouter *	getTopLevelRouter () const
	Gets the topmost (root) ProcessorRouter by traversing parent routers.

virtual void	registerInput (Input *input, int index)
	Registers a new input, appending it to the input list.

virtual Output *	registerOutput (Output *output, int index)
	Registers a new Output in the output list at a specified index.

virtual void	registerInput (Input *input)
	Registers a new Input by appending it to the end of the input list.

virtual Output *	registerOutput (Output *output)
	Registers a new Output by appending it to the end of the output list.

force_inline int	numInputs () const
	Returns the total number of Input pointers (owned or otherwise).

force_inline int	numOutputs () const
	Returns the total number of Output pointers (owned or otherwise).

force_inline int	numOwnedInputs () const
	Returns how many Input objects this Processor owns.

force_inline int	numOwnedOutputs () const
	Returns how many Output objects this Processor owns.

force_inline Input *	input (unsigned int index=0) const
	Retrieves the Input pointer at a given index.

force_inline bool	isInputSourcePolyphonic (int index=0)
	Checks if the input source at a given index is polyphonic.

force_inline Input *	ownedInput (unsigned int index=0) const
	Retrieves an owned Input pointer at a given index.

force_inline Output *	output (unsigned int index=0) const
	Retrieves the Output pointer at a given index.

force_inline Output *	ownedOutput (unsigned int index=0) const
	Retrieves an owned Output pointer at a given index.

void	setPluggingStart (int start)
	Sets the position at which `plugNext` starts searching for an open input.

Public Member Functions inherited from vital::SynthFilter
virtual	~SynthFilter ()
	Virtual destructor for the SynthFilter base class.

Static Public Member Functions
static force_inline mono_float	computeSvfOnePoleFilterCoefficient (mono_float frequency_ratio)
	Computes a one-pole SVF coefficient from a normalized frequency ratio.

static const SvfCoefficientLookup *	getSvfCoefficientLookup ()
	Retrieves a pointer to the global SVF coefficient lookup table.

Static Public Member Functions inherited from vital::SynthFilter
static force_inline mono_float	computeOnePoleFilterCoefficient (mono_float frequency_ratio)
	Computes a one-pole filter coefficient from a frequency ratio.

static const CoefficientLookup *	getCoefficientLookup ()
	Retrieves a pointer to the static coefficient lookup table.

static SynthFilter *	createFilter (constants::FilterModel model)
	Factory method for creating a specialized filter based on a model enum.

Static Public Attributes
static constexpr mono_float	kDefaultMinResonance = 0.5f
	Default minimum resonance used when filtering (if not overridden).

static constexpr mono_float	kDefaultMaxResonance = 16.0f
	Default maximum resonance used when filtering (if not overridden).

static constexpr mono_float	kMinCutoff = 1.0f
	Minimum allowed cutoff frequency in Hz for the filter.

static constexpr mono_float	kMaxGain = 15.0f
	Maximum gain in dB for shelf or gain-based operations.

static constexpr mono_float	kMinGain = -15.0f
	Minimum gain in dB for shelf or gain-based operations.

static const SvfCoefficientLookup	svf_coefficient_lookup_
	A static global lookup table instance for SVF coefficients.

Static Public Attributes inherited from vital::SynthFilter
static const CoefficientLookup	coefficient_lookup_
	Static instance of the coefficient lookup table, generated at compile time.

Additional Inherited Members
Protected Member Functions inherited from vital::Processor
Output *	addOutput (int oversample=1)
	Creates and registers a new Output. Handles control rate vs. audio rate.

Input *	addInput ()
	Creates and registers a new Input, initially connected to null_source_.

Protected Attributes inherited from vital::Processor
std::shared_ptr< ProcessorState >	state_
	Shared state (sample rate, oversample, etc.)

int	plugging_start_
	The index at which `plugNext` starts searching for an unplugged input.

std::vector< std::shared_ptr< Input > >	owned_inputs_
	Inputs owned by this Processor.

std::vector< std::shared_ptr< Output > >	owned_outputs_
	Outputs owned by this Processor.

std::shared_ptr< std::vector< Input * > >	inputs_
	All inputs, owned or external.

std::shared_ptr< std::vector< Output * > >	outputs_
	All outputs, owned or external.

ProcessorRouter *	router_
	The ProcessorRouter that manages this Processor.

Protected Attributes inherited from vital::SynthFilter
FilterState	filter_state_
	Internal storage of the most recent FilterState, used by derived filters.

Static Protected Attributes inherited from vital::Processor
static const Output	null_source_
	A null (dummy) source used for unconnected inputs.

Detailed Description

A state-variable filter (SVF) implementation, supporting multiple filter types (12/24 dB, shelving, dual modes).

The DigitalSvf class provides a flexible filter design that can morph between low-pass, high-pass, band-pass, notch, peak, and specialized dual filter modes. It optionally supports a basic or advanced processing path, drive compensation, and user-defined resonance bounds.

Member Typedef Documentation

◆ SvfCoefficientLookup

OneDimLookup<computeSvfOnePoleFilterCoefficient, 2048> vital::DigitalSvf::SvfCoefficientLookup

A lookup table type for quickly converting frequency ratios into filter coefficients.

Constructor & Destructor Documentation

◆ DigitalSvf()

vital::DigitalSvf::DigitalSvf ( )

Constructor that initializes the filter’s internal states.

Constructs a DigitalSvf object, resetting its internal states to defaults.

◆ ~DigitalSvf()

virtual vital::DigitalSvf::~DigitalSvf ( )

inlinevirtual

Default destructor.

Member Function Documentation

◆ clone()

virtual Processor * vital::DigitalSvf::clone ( ) const

inlineoverridevirtual

Creates a clone of this filter by invoking the copy constructor.

Returns: A pointer to a newly allocated DigitalSvf object.

Implements vital::Processor.

◆ computeSvfOnePoleFilterCoefficient()

static force_inline mono_float vital::DigitalSvf::computeSvfOnePoleFilterCoefficient ( mono_float frequency_ratio )

inlinestatic

Computes a one-pole SVF coefficient from a normalized frequency ratio.

Ensures the ratio is clamped so that tan() doesn’t blow up near Nyquist.

Parameters

frequency_ratio The normalized frequency in [0..0.5).

Returns: The computed one-pole filter coefficient.

◆ getBandAmount()

poly_float vital::DigitalSvf::getBandAmount ( ) const

inline

Retrieves the current band-frequency mix portion.

Returns: The band portion mix amount.

◆ getDrive()

poly_float vital::DigitalSvf::getDrive ( ) const

inline

Retrieves the final drive (post drive compensation) used in the filter.

Returns: The computed drive multiplied by post_multiply.

◆ getHighAmount()

poly_float vital::DigitalSvf::getHighAmount ( ) const

inline

Retrieves the current high-frequency mix portion.

Returns: The high portion mix amount.

◆ getHighAmount24()

poly_float vital::DigitalSvf::getHighAmount24 ( int style ) const

inline

Helper for a 24 dB filter style that may swap low/high in a dual notch band.

Parameters

style An integer enumerating the filter style.

Returns: The appropriate high amount for a 24 dB style.

◆ getLowAmount()

poly_float vital::DigitalSvf::getLowAmount ( ) const

inline

Retrieves the current low-frequency mix portion.

Returns: The low portion mix amount.

◆ getLowAmount24()

poly_float vital::DigitalSvf::getLowAmount24 ( int style ) const

inline

Helper for a 24 dB filter style that may swap low/high in a dual notch band.

Parameters

style An integer enumerating the filter style.

Returns: The appropriate low amount for a 24 dB style.

◆ getMidiCutoff()

poly_float vital::DigitalSvf::getMidiCutoff ( ) const

inline

Retrieves the current MIDI-based cutoff frequency.

Returns: The stored MIDI cutoff value.

◆ getResonance()

poly_float vital::DigitalSvf::getResonance ( ) const

inline

Retrieves the current resonance value (inverted if needed).

Returns: The stored resonance used by the filter.

◆ getSvfCoefficientLookup()

static const SvfCoefficientLookup * vital::DigitalSvf::getSvfCoefficientLookup ( )

inlinestatic

Retrieves a pointer to the global SVF coefficient lookup table.

Returns: Pointer to the svf_coefficient_lookup_.

◆ hardReset()

void vital::DigitalSvf::hardReset ( )

overridevirtual

Performs a complete reset of the filter states for all voices.

Performs a complete reset of all internal states for every voice.

Reimplemented from vital::Processor.

◆ process()

void vital::DigitalSvf::process ( int num_samples )

overridevirtual

Processes a block of samples by pulling from the primary audio input and computing the SVF output. Delegates to processWithInput().

Processes a block of samples by reading from the main audio input, then calls processWithInput().

Parameters

num_samples Number of samples to process.

Implements vital::Processor.

◆ process12()

void vital::DigitalSvf::process12	(	const poly_float *	audio_in,
		int	num_samples,
		poly_float	current_resonance,
		poly_float	current_drive,
		poly_float	current_post_multiply,
		FilterValues &	blends )

Processes a 12 dB filter style, iterating through the block.

Parameters

audio_in	Input audio data.
num_samples	Number of samples in the buffer.
current_resonance	Current resonance value (possibly interpolated).
current_drive	Current drive value.
current_post_multiply	Additional multiplier after the filter.
blends	Filter mix gains (low/band/high).

◆ process24()

void vital::DigitalSvf::process24	(	const poly_float *	audio_in,
		int	num_samples,
		poly_float	current_resonance,
		poly_float	current_drive,
		poly_float	current_post_multiply,
		FilterValues &	blends )

Processes a 24 dB filter style, adding additional stages.

Parameters

audio_in	Input audio data.
num_samples	Number of samples in the buffer.
current_resonance	Current resonance value.
current_drive	Current drive value.
current_post_multiply	Additional multiplier after the filter.
blends	Filter mix gains (low/band/high).

◆ processBasic12()

void vital::DigitalSvf::processBasic12	(	const poly_float *	audio_in,
		int	num_samples,
		poly_float	current_resonance,
		poly_float	current_drive,
		poly_float	current_post_multiply,
		FilterValues &	blends )

Processes a simpler 12 dB filter style, skipping extra color or overshoot logic.

Parameters

audio_in	Input audio data.
num_samples	Number of samples in the buffer.
current_resonance	Current resonance value.
current_drive	Current drive value.
current_post_multiply	Additional multiplier after the filter.
blends	Filter mix gains (low/band/high).

◆ processBasic24()

void vital::DigitalSvf::processBasic24	(	const poly_float *	audio_in,
		int	num_samples,
		poly_float	current_resonance,
		poly_float	current_drive,
		poly_float	current_post_multiply,
		FilterValues &	blends )

Processes a simpler 24 dB filter style, skipping advanced processing.

Parameters

audio_in	Input audio data.
num_samples	Number of samples in the buffer.
current_resonance	Current resonance value.
current_drive	Current drive value.
current_post_multiply	Additional multiplier after the filter.
blends	Filter mix gains (low/band/high).

◆ processDual()

void vital::DigitalSvf::processDual	(	const poly_float *	audio_in,
		int	num_samples,
		poly_float	current_resonance,
		poly_float	current_drive,
		poly_float	current_post_multiply,
		FilterValues &	blends1,
		FilterValues &	blends2 )

Processes a dual filter mode, e.g., dual notch + band pass.

Splits filter processing into two sets of FilterValues (blends1 and blends2).

Parameters

audio_in	Input audio data.
num_samples	Number of samples to process.
current_resonance	Current resonance value.
current_drive	Current drive value.
current_post_multiply	Additional multiplier.
blends1	The first set of filter mixes (low/band/high).
blends2	The second set of filter mixes (low/band/high).

◆ processWithInput()

void vital::DigitalSvf::processWithInput	(	const poly_float *	audio_in,
		int	num_samples )

overridevirtual

Processes a block of samples using a provided input buffer.

Detailed logic for processing a block of samples, handling filter style and interpolation.

Applies configured filter settings to compute the final output.

Parameters

audio_in	Pointer to the input audio buffer.
num_samples	Number of samples to process.
audio_in	Pointer to the input audio buffer.
num_samples	Number of samples to process.

Reimplemented from vital::Processor.

◆ reset()

void vital::DigitalSvf::reset ( poly_mask reset_mask )

overridevirtual

Resets internal filter states for voices specified by the reset_masks.

Resets specified voices in the filter’s internal state variables.

Parameters

reset_masks	Mask specifying which voices to reset.
reset_masks	The poly_mask selecting which voices to reset.

Reimplemented from vital::Processor.

◆ setBasic()

void vital::DigitalSvf::setBasic ( bool basic )

inline

Sets whether this filter should use a simpler, “basic” processing path.

Parameters

basic If true, uses the simplified process path.

◆ setDriveCompensation()

void vital::DigitalSvf::setDriveCompensation ( bool drive_compensation )

inline

Enables or disables drive compensation (reducing drive as resonance increases).

Parameters

drive_compensation If true, drive is reduced as resonance goes up.

◆ setResonanceBounds()

void vital::DigitalSvf::setResonanceBounds	(	mono_float	min,
		mono_float	max )

Sets the minimum and maximum resonance for the filter (used in resonance interpolation).

Parameters

min	The new minimum resonance value.
max	The new maximum resonance value.

◆ setupFilter()

void vital::DigitalSvf::setupFilter ( const FilterState & filter_state )

overridevirtual

Configures this SVF based on a FilterState (cutoff, resonance, style, etc.).

Configures the filter based on the provided FilterState, computing resonance, drive, etc.

Parameters

filter_state	The FilterState containing all relevant parameters.
filter_state	The FilterState containing style, cutoff, resonance, gain, etc.

Implements vital::SynthFilter.

◆ tick()

force_inline poly_float vital::DigitalSvf::tick	(	poly_float	audio_in,
		poly_float	coefficient,
		poly_float	resonance,
		poly_float	drive,
		FilterValues &	blends )

Applies advanced distortion to the input while performing a single SVF tick (12 dB).

Tick function for advanced, saturating 12 dB filtering.

Parameters

audio_in	The current input sample.
drive	Amount of drive (pre-gain).
resonance	The filter resonance.
coefficient	The filter coefficient derived from cutoff.
blends	The low/band/high mix values.

Returns: The final filter output for the sample.

Parameters

audio_in	The current input sample.
coefficient	The computed filter coefficient.
resonance	The filter resonance.
drive	Input drive multiplier.
blends	The filter’s low/band/high mix.

Returns: The final processed sample with saturation.

◆ tick24()

force_inline poly_float vital::DigitalSvf::tick24	(	poly_float	audio_in,
		poly_float	coefficient,
		poly_float	resonance,
		poly_float	drive,
		FilterValues &	blends )

Tick function for a 24 dB multi-stage filter, adding an additional pre-stage.

Tick function for 24 dB filtering, performing a pre-stage, saturating, then a second SVF pass.

Parameters

audio_in	The current input sample.
coefficient	The filter coefficient.
resonance	The filter resonance.
drive	The input drive multiplier.
blends	The filter’s mix values (low/band/high).

Returns: The filter output for the sample.

Parameters

audio_in	The input sample.
coefficient	The filter coefficient.
resonance	The filter resonance.
drive	Input drive multiplier.
blends	Filter mixing parameters.

Returns: Filtered sample after 24 dB of attenuation.

◆ tickBasic()

force_inline poly_float vital::DigitalSvf::tickBasic	(	poly_float	audio_in,
		poly_float	coefficient,
		poly_float	resonance,
		poly_float	drive,
		FilterValues &	blends )

A basic (non-distorting) single SVF tick for a 12 dB filter style.

A simpler single tick for a 12 dB filter, skipping advanced distortion.

Parameters

audio_in	The current input sample.
coefficient	The filter coefficient derived from cutoff.
resonance	The filter resonance.
drive	The input drive multiplier.
blends	The filter’s mix values for low/band/high output.

Returns: The filter output for the sample.

Parameters

audio_in	The input sample.
coefficient	The filter coefficient from the lookup.
resonance	The filter resonance (inverted).
drive	The input drive multiplier.
blends	Low/band/high mix factors.

Returns: Filtered sample output.

◆ tickBasic24()

force_inline poly_float vital::DigitalSvf::tickBasic24	(	poly_float	audio_in,
		poly_float	coefficient,
		poly_float	resonance,
		poly_float	drive,
		FilterValues &	blends )

A simpler 24 dB tick function without advanced distortion or color.

Basic, non-distorting 24 dB filter tick.

Parameters

audio_in	The current input sample.
coefficient	The filter coefficient.
resonance	The filter resonance.
drive	The input drive multiplier.
blends	The filter’s mix values (low/band/high).

Returns: Filtered sample.

Parameters

audio_in	The input sample.
coefficient	The filter coefficient.
resonance	The filter resonance.
drive	Input drive multiplier.
blends	Filter mixing parameters.

Returns: Final 24 dB filter output.

◆ tickDual()

force_inline poly_float vital::DigitalSvf::tickDual	(	poly_float	audio_in,
		poly_float	coefficient,
		poly_float	resonance,
		poly_float	drive,
		FilterValues &	blends1,
		FilterValues &	blends2 )

Tick function for a dual filter approach, e.g. notch + band, etc.

A dual-stage filter approach, e.g., for dual notch/band passes.

Parameters

audio_in	The current input sample.
coefficient	The filter coefficient (cutoff).
resonance	The filter resonance.
drive	The input drive multiplier.
blends1	Low/band/high mixing for the first filter pass.
blends2	Low/band/high mixing for the second filter pass.

Returns: Filtered sample after both filter passes.

Parameters

audio_in	The input sample.
coefficient	The filter coefficient.
resonance	Filter resonance.
drive	Input drive multiplier.
blends1	The first filter stage blends.
blends2	The second filter stage blends.

Returns: The final sample after going through both filter passes.

Member Data Documentation

◆ kDefaultMaxResonance

mono_float vital::DigitalSvf::kDefaultMaxResonance = 16.0f

staticconstexpr

Default maximum resonance used when filtering (if not overridden).

◆ kDefaultMinResonance

mono_float vital::DigitalSvf::kDefaultMinResonance = 0.5f

staticconstexpr

Default minimum resonance used when filtering (if not overridden).

◆ kMaxGain

mono_float vital::DigitalSvf::kMaxGain = 15.0f

staticconstexpr

Maximum gain in dB for shelf or gain-based operations.

◆ kMinCutoff

mono_float vital::DigitalSvf::kMinCutoff = 1.0f

staticconstexpr

Minimum allowed cutoff frequency in Hz for the filter.

◆ kMinGain

mono_float vital::DigitalSvf::kMinGain = -15.0f

staticconstexpr

Minimum gain in dB for shelf or gain-based operations.

◆ svf_coefficient_lookup_

const DigitalSvf::SvfCoefficientLookup vital::DigitalSvf::svf_coefficient_lookup_

static

A static global lookup table instance for SVF coefficients.

The global SVF coefficient lookup table instance.

Initializes a 2048-entry table converting normalized frequency ratios to one-pole filter coefficients using computeSvfOnePoleFilterCoefficient().

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

/Users/davidvogel/repos/VitalHelp/src/synthesis/filters/digital_svf.h
/Users/davidvogel/repos/VitalHelp/src/synthesis/filters/digital_svf.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ SvfCoefficientLookup

Constructor & Destructor Documentation

◆ DigitalSvf()

◆ ~DigitalSvf()

Member Function Documentation

◆ clone()

◆ computeSvfOnePoleFilterCoefficient()

◆ getBandAmount()

◆ getDrive()

◆ getHighAmount()

◆ getHighAmount24()

◆ getLowAmount()

◆ getLowAmount24()

◆ getMidiCutoff()

◆ getResonance()

◆ getSvfCoefficientLookup()

◆ hardReset()

◆ process()

◆ process12()

◆ process24()

◆ processBasic12()

◆ processBasic24()

◆ processDual()

◆ processWithInput()

◆ reset()

◆ setBasic()

◆ setDriveCompensation()

◆ setResonanceBounds()

◆ setupFilter()

◆ tick()

◆ tick24()

◆ tickBasic()

◆ tickBasic24()

◆ tickDual()

Member Data Documentation

◆ kDefaultMaxResonance

◆ kDefaultMinResonance

◆ kMaxGain

◆ kMinCutoff

◆ kMinGain

◆ svf_coefficient_lookup_