juce::dsp::StateVariableFilter::Filter< SampleType > Class Template Reference

An IIR filter that can perform low, band and high-pass filtering on an audio signal, with 12 dB of attenuation per octave, using a TPT structure, designed for fast modulation (see Vadim Zavalishin's documentation about TPT structures for more information). More...

#include <juce_StateVariableFilter.h>

Collaboration diagram for juce::dsp::StateVariableFilter::Filter< SampleType >:

Public Types
using	NumericType = typename SampleTypeHelpers::ElementType< SampleType >::Type
	The NumericType is the underlying primitive type used by the SampleType (which could be either a primitive or vector) More...
using	ParametersPtr = typename Parameters< NumericType >::Ptr
	A typedef for a ref-counted pointer to the coefficients object. More...

Public Member Functions
	Filter (const Filter &)=default
	Creates a copy of another filter. More...
	Filter (Filter &&)=default
	Move constructor. More...
void	prepare (const ProcessSpec &) noexcept
	Initialization of the filter. More...
template<typename ProcessContext >
void	process (const ProcessContext &context) noexcept
SampleType JUCE_VECTOR_CALLTYPE	processSample (SampleType sample) noexcept
	Processes a single sample, without any locking or checking. More...
void	reset () noexcept
	Resets the filter's processing pipeline. More...
void	snapToZero () noexcept
	Ensure that the state variables are rounded to zero if the state variables are denormals. More...

Public Attributes
Parameters< NumericType >::Ptr	parameters
	The parameters of the state variable filter. More...

Private Member Functions
template<bool isBypassed, typename Parameters< NumericType >::Type type>
void	processBlock (const SampleType *input, SampleType *output, size_t n) noexcept
template<bool isBypassed, typename ProcessContext >
void	processInternal (const ProcessContext &context) noexcept
template<bool isBypassed, typename Parameters< NumericType >::Type type>
SampleType JUCE_VECTOR_CALLTYPE	processLoop (SampleType sample, Parameters< NumericType > &state) noexcept

Private Attributes
SampleType	s1
SampleType	s2
std::array< SampleType, 3 >	y

Detailed Description

template<typename SampleType>
class juce::dsp::StateVariableFilter::Filter< SampleType >

An IIR filter that can perform low, band and high-pass filtering on an audio signal, with 12 dB of attenuation per octave, using a TPT structure, designed for fast modulation (see Vadim Zavalishin's documentation about TPT structures for more information).

Its behaviour is based on the analog state variable filter circuit.

Note: The bandpass here is not the one in the RBJ CookBook as its gain can be higher than 0 dB. For the classic 0 dB bandpass, we need to multiply the result by R2.

Note 2: Using this class prevents some loud audio artefacts commonly encountered when changing the cutoff frequency using other filter simulation structures and IIR filter classes. However, this class may still require additional smoothing for cutoff frequency changes.

see IIRFilter, SmoothedValue

@tags{DSP}

Member Typedef Documentation

NumericType

template<typename SampleType >

using juce::dsp::StateVariableFilter::Filter< SampleType >::NumericType = typename SampleTypeHelpers::ElementType<SampleType>::Type

The NumericType is the underlying primitive type used by the SampleType (which could be either a primitive or vector)

ParametersPtr

template<typename SampleType >

using juce::dsp::StateVariableFilter::Filter< SampleType >::ParametersPtr = typename Parameters<NumericType>::Ptr

A typedef for a ref-counted pointer to the coefficients object.

Constructor & Destructor Documentation

Filter() [1/2]

template<typename SampleType >

juce::dsp::StateVariableFilter::Filter< SampleType >::Filter ( const Filter< SampleType > &  )

default

Creates a copy of another filter.

Filter() [2/2]

template<typename SampleType >

juce::dsp::StateVariableFilter::Filter< SampleType >::Filter ( Filter< SampleType > &&  )

default

Move constructor.

Member Function Documentation

prepare()

template<typename SampleType >

void juce::dsp::StateVariableFilter::Filter< SampleType >::prepare ( const ProcessSpec &  )

inlinenoexcept

Initialization of the filter.

References juce::dsp::StateVariableFilter::Filter< SampleType >::reset().

process()

template<typename SampleType >

template<typename ProcessContext >

void juce::dsp::StateVariableFilter::Filter< SampleType >::process ( const ProcessContext &  context )

inlinenoexcept

References juce::gl::value.

processBlock()

template<typename SampleType >

template<bool isBypassed, typename Parameters< NumericType >::Type type>

void juce::dsp::StateVariableFilter::Filter< SampleType >::processBlock ( const SampleType *  input, SampleType *  output, size_t  n  )

inlineprivatenoexcept

References juce::gl::input, juce::gl::n, juce::gl::output, juce::dsp::StateVariableFilter::Filter< SampleType >::parameters, and juce::dsp::StateVariableFilter::Filter< SampleType >::snapToZero().

processInternal()

template<typename SampleType >

template<bool isBypassed, typename ProcessContext >

void juce::dsp::StateVariableFilter::Filter< SampleType >::processInternal ( const ProcessContext &  context )

inlineprivatenoexcept

References juce::gl::dst, jassert, jassertfalse, juce::gl::n, juce::dsp::StateVariableFilter::Filter< SampleType >::parameters, and juce::gl::src.

processLoop()

template<typename SampleType >

template<bool isBypassed, typename Parameters< NumericType >::Type type>

SampleType JUCE_VECTOR_CALLTYPE juce::dsp::StateVariableFilter::Filter< SampleType >::processLoop ( SampleType  sample, Parameters< NumericType > &  state  )

inlineprivatenoexcept

References juce::dsp::isBypassed(), juce::dsp::StateVariableFilter::Filter< SampleType >::s1, juce::dsp::StateVariableFilter::Filter< SampleType >::s2, juce::gl::type, and juce::dsp::StateVariableFilter::Filter< SampleType >::y.

processSample()

template<typename SampleType >

SampleType JUCE_VECTOR_CALLTYPE juce::dsp::StateVariableFilter::Filter< SampleType >::processSample ( SampleType  sample )

inlinenoexcept

Processes a single sample, without any locking or checking.

Use this if you need processing of a single value.

References jassertfalse, and juce::dsp::StateVariableFilter::Filter< SampleType >::parameters.

reset()

template<typename SampleType >

void juce::dsp::StateVariableFilter::Filter< SampleType >::reset ( )

inlinenoexcept

Resets the filter's processing pipeline.

References juce::dsp::StateVariableFilter::Filter< SampleType >::s1, and juce::dsp::StateVariableFilter::Filter< SampleType >::s2.

Referenced by juce::dsp::StateVariableFilter::Filter< SampleType >::prepare().

snapToZero()

template<typename SampleType >

void juce::dsp::StateVariableFilter::Filter< SampleType >::snapToZero ( )

inlinenoexcept

Ensure that the state variables are rounded to zero if the state variables are denormals.

This is only needed if you are doing sample by sample processing.

References juce::dsp::StateVariableFilter::Filter< SampleType >::s1, juce::dsp::StateVariableFilter::Filter< SampleType >::s2, and juce::dsp::util::snapToZero().

Referenced by juce::dsp::StateVariableFilter::Filter< SampleType >::processBlock().

Member Data Documentation

parameters

template<typename SampleType >

Parameters<NumericType>::Ptr juce::dsp::StateVariableFilter::Filter< SampleType >::parameters

The parameters of the state variable filter.

It's up to the caller to ensure that these parameters are modified in a thread-safe way.

Referenced by juce::dsp::StateVariableFilter::Filter< SampleType >::processBlock(), juce::dsp::StateVariableFilter::Filter< SampleType >::processInternal(), and juce::dsp::StateVariableFilter::Filter< SampleType >::processSample().

s1

template<typename SampleType >

SampleType juce::dsp::StateVariableFilter::Filter< SampleType >::s1

private

Referenced by juce::dsp::StateVariableFilter::Filter< SampleType >::processLoop(), juce::dsp::StateVariableFilter::Filter< SampleType >::reset(), and juce::dsp::StateVariableFilter::Filter< SampleType >::snapToZero().

s2

template<typename SampleType >

SampleType juce::dsp::StateVariableFilter::Filter< SampleType >::s2

private

Referenced by juce::dsp::StateVariableFilter::Filter< SampleType >::processLoop(), juce::dsp::StateVariableFilter::Filter< SampleType >::reset(), and juce::dsp::StateVariableFilter::Filter< SampleType >::snapToZero().

y

template<typename SampleType >

std::array<SampleType, 3> juce::dsp::StateVariableFilter::Filter< SampleType >::y

private

Referenced by juce::dsp::StateVariableFilter::Filter< SampleType >::processLoop().

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

• juce_StateVariableFilter.h