Nsound::FilterParametricEqualizer Class Reference

Implementation of Zoelzer's parametric equalizer filters, with some modifications by the author. More...

#include <Nsound/FilterParametricEqualizer.h>

Inheritance diagram for Nsound::FilterParametricEqualizer:

Public Types
enum	Type { PEAKING, LOW_SHELF, HIGH_SHELF }

Public Member Functions
	FilterParametricEqualizer (const Type &type, const float64 &sample_rate, const float64 &frequency, const float64 &resonance=0.707106781187, const float64 &boost_dB=0.0)
	boost is in dB More...
virtual	~FilterParametricEqualizer ()
AudioStream	filter (const AudioStream &x)
AudioStream	filter (const AudioStream &x, const Buffer &frequencies)
AudioStream	filter (const AudioStream &x, const Buffer &frequencies, const Buffer &resonance)
AudioStream	filter (const AudioStream &x, const Buffer &frequencies, const Buffer &resonance, const Buffer &boost_dB)
	boost is in dB More...
Buffer	filter (const Buffer &x)
Buffer	filter (const Buffer &x, const Buffer &frequencies)
Buffer	filter (const Buffer &x, const Buffer &frequencies, const Buffer &resonance)
Buffer	filter (const Buffer &x, const Buffer &frequencies, const Buffer &resonance, const Buffer &boost_dB)
	boost is in dB More...
float64	filter (const float64 &x)
float64	filter (const float64 &x, const float64 &frequency)
float64	filter (const float64 &x, const float64 &frequency, const float64 &resonance)
	boost is in dB More...
float64	filter (const float64 &x, const float64 &frequency, const float64 &resonance, const float64 &boost_dB)
	boost is in dB More...
void	makeKernel (const float64 &frequency, const float64 &resonance, const float64 &boost)
void	plot (boolean show_fc=true, boolean show_phase=false)
void	reset ()
void	setRealtime (bool flag)
AudioStream	filter (const AudioStream &x, const float64 &frequency)
Buffer	filter (const Buffer &x, const float64 &frequency)
Buffer	getFrequencyAxis (const uint32 n_fft=8192)
Buffer	getFrequencyResponse (const uint32 n_fft=8192)
Buffer	getImpulseResponse (const uint32 n_samples=8192)
virtual uint32	getKernelSize () const
Buffer	getPhaseResponse ()
float64	getSampleRate () const
void	plot (boolean show_phase=false)

Protected Attributes
Type	type_
float64	frequency_
float64	resonance_
float64	boost_
float64 *	a_
float64 *	b_
float64 *	x_history_
float64 *	x_ptr_
float64 *	x_end_ptr_
float64 *	y_history_
float64 *	y_ptr_
float64 *	y_end_ptr_
KernelCache	kernel_cache_
float64	sample_rate_
float64	two_pi_over_sample_rate_
float64	sample_time_
uint32	kernel_size_
bool	is_realtime_

Private Member Functions
	FilterParametricEqualizer (const FilterParametricEqualizer &copy)
FilterParametricEqualizer &	operator= (const FilterParametricEqualizer &rhs)

Detailed Description

Implementation of Zoelzer's parametric equalizer filters, with some modifications by the author.

Below are the formulas for the 3 different types of parametric equalizer filters.

f = Frequency in Hz sr = Sample Rate in samples per second V = Percent boost (1.0 = no boost, < 1.0 = cut signal, > 1.0 boost signal) Q = Resonance or Q of the filter, sqrt(1/2) == no resonance

omega = 2*pi*f/sr K = tan(omega/2)

a0 = 1 + sqrt(2*V)*K + V*K^2 a1 = 2*(V*K^2 - 1) a2 = 1 - sqrt(2*V)*K + V*K^2

b0 = 1 + K/Q + K^2 b1 = 2*(K^2 - 1) b2 = 1 - K/Q + K^2

The formula for the High Shelf filter is:

omega = 2*pi*f/sr K = tan((pi-omega)/2)

a0 = 1 + sqrt(2*V)*K + V*K^2 a1 = -2*(V*K^2 - 1) a1 = 1 - sqrt(2*V)*K + V*K^2

b0 = 1 + K/Q + K^2 b1 = -2*(K^2 - 1) b2 = 1 - K/Q + K^2

The formula for the Peaking filter is:

omega = 2*pi*f/sr K = tan(omega/2)

a0 = 1 + V*K/2 + K^2 a1 = 2*(K^2 - 1) a2 = 1 - V*K/2 + K^2

b0 = 1 + K/Q + K^2 b1 = 2*(K^2 - 1) b2 = 1 - K/Q + K^2

Definition at line 98 of file FilterParametricEqualizer.h.

Member Enumeration Documentation

enum Nsound::FilterParametricEqualizer::Type

Enumerator
PEAKING
LOW_SHELF
HIGH_SHELF

Definition at line 102 of file FilterParametricEqualizer.h.

    {
        PEAKING,
        LOW_SHELF,
        HIGH_SHELF
    };

Constructor & Destructor Documentation

FilterParametricEqualizer::FilterParametricEqualizer	(	const Type &	type,
		const float64 &	sample_rate,
		const float64 &	frequency,
		const float64 &	resonance = 0.707106781187,
		const float64 &	boost_dB = 0.0
	)

boost is in dB

Definition at line 45 of file FilterParametricEqualizer.cc.

References N_POLES, reset(), x_end_ptr_, x_history_, x_ptr_, y_end_ptr_, y_history_, and y_ptr_.

    :
    Filter(sample_rate),
    type_(type),
    frequency_(frequency),
    resonance_(resonance),
    boost_(boost),
    a_(new float64 [N_POLES]),
    b_(new float64 [N_POLES]),
    x_history_(NULL),
    x_ptr_(NULL),
    x_end_ptr_(NULL),
    y_history_(NULL),
    y_ptr_(NULL),
    y_end_ptr_(NULL),
    kernel_cache_()
{
    x_history_ = new float64 [N_POLES + 1];
    x_ptr_     = x_history_;
    x_end_ptr_ = x_history_ + N_POLES + 1;

    y_history_ = new float64 [N_POLES + 1];
    y_ptr_     = y_history_;
    y_end_ptr_ = y_history_ + N_POLES + 1;

    reset();
}

FilterParametricEqualizer::~FilterParametricEqualizer ( )

virtual

Definition at line 80 of file FilterParametricEqualizer.cc.

References a_, b_, x_history_, and y_history_.

{
    delete [] a_;
    delete [] b_;
    delete [] x_history_;
    delete [] y_history_;
}

Nsound::FilterParametricEqualizer::FilterParametricEqualizer ( const FilterParametricEqualizer &  copy )

private

Member Function Documentation

AudioStream FilterParametricEqualizer::filter

(

const AudioStream &

x

)

Definition at line 90 of file FilterParametricEqualizer.cc.

References Nsound::AudioStream::getNChannels(), and Nsound::AudioStream::getSampleRate().

Referenced by filter(), FilterParametricEqualizer_UnitTest(), and Nsound::DrumKickBass::play().

{
    uint32 n_channels = x.getNChannels();

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel]);
    }

    return y;
}

AudioStream FilterParametricEqualizer::filter	(	const AudioStream &	x,
		const Buffer &	frequencies
	)

Definition at line 106 of file FilterParametricEqualizer.cc.

References filter(), Nsound::AudioStream::getNChannels(), and Nsound::AudioStream::getSampleRate().

{
    uint32 n_channels = x.getNChannels();

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequencies);
    }

    return y;
}

AudioStream FilterParametricEqualizer::filter	(	const AudioStream &	x,
		const Buffer &	frequencies,
		const Buffer &	resonance
	)

Definition at line 122 of file FilterParametricEqualizer.cc.

References filter(), Nsound::AudioStream::getNChannels(), and Nsound::AudioStream::getSampleRate().

{
    uint32 n_channels = x.getNChannels();

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequencies, resonance);
    }

    return y;
}

AudioStream FilterParametricEqualizer::filter	(	const AudioStream &	x,
		const Buffer &	frequencies,
		const Buffer &	resonance,
		const Buffer &	boost_dB
	)

boost is in dB

Definition at line 141 of file FilterParametricEqualizer.cc.

References filter(), Nsound::AudioStream::getNChannels(), and Nsound::AudioStream::getSampleRate().

{
    uint32 n_channels = x.getNChannels();

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequencies, resonance, boost);
    }

    return y;
}

Buffer FilterParametricEqualizer::filter

(

const Buffer &

x

)

Definition at line 162 of file FilterParametricEqualizer.cc.

References filter(), Nsound::Buffer::getLength(), and reset().

{
    reset();

    uint32 n_samples = x.getLength();

    Buffer y;

    for(uint32 n = 0; n < n_samples; ++n)
    {
        y << filter(x[n]);
    }

    return y;
}

Buffer FilterParametricEqualizer::filter	(	const Buffer &	x,
		const Buffer &	frequencies
	)

Definition at line 180 of file FilterParametricEqualizer.cc.

References filter(), Nsound::Buffer::getLength(), and reset().

{
    reset();

    uint32 n_samples = x.getLength();
    uint32 n_freqs   = frequencies.getLength();

    Buffer y;

    for(uint32 n = 0; n < n_samples; ++n)
    {
        y << filter(x[n], frequencies[n % n_freqs]);
    }

    return y;
}

Buffer FilterParametricEqualizer::filter	(	const Buffer &	x,
		const Buffer &	frequencies,
		const Buffer &	resonance
	)

Definition at line 199 of file FilterParametricEqualizer.cc.

References filter(), Nsound::Buffer::getLength(), and reset().

{
    reset();

    uint32 n_samples = x.getLength();
    uint32 n_freqs   = frequencies.getLength();
    uint32 n_rezzies  = resonance.getLength();

    Buffer y;

    for(uint32 n = 0; n < n_samples; ++n)
    {
        y << filter(x[n], frequencies[n % n_freqs], resonance[n % n_rezzies]);
    }

    return y;
}

Buffer FilterParametricEqualizer::filter	(	const Buffer &	x,
		const Buffer &	frequencies,
		const Buffer &	resonance,
		const Buffer &	boost_dB
	)

boost is in dB

Definition at line 222 of file FilterParametricEqualizer.cc.

References filter(), Nsound::Buffer::getLength(), and reset().

{
    reset();

    uint32 n_samples = x.getLength();
    uint32 n_freqs   = frequencies.getLength();
    uint32 n_rezzies = resonance.getLength();
    uint32 n_boosts  = boost.getLength();

    Buffer y;

    for(uint32 n = 0; n < n_samples; ++n)
    {
        y << filter(x[n],
            frequencies[n % n_freqs],
            resonance[n % n_rezzies],
            boost[n % n_boosts]);
    }

    return y;
}

float64 FilterParametricEqualizer::filter ( const float64 &  x )

virtual

Implements Nsound::Filter.

Definition at line 250 of file FilterParametricEqualizer.cc.

References a_, b_, N_POLES, x_end_ptr_, x_history_, x_ptr_, y_end_ptr_, y_history_, and y_ptr_.

{
    // Write x to history
    *x_ptr_ = x;

    // Increment history pointer
    ++x_ptr_;

    // Bounds check
    if(x_ptr_ >= x_end_ptr_)
    {
        x_ptr_ = x_history_;
    }

    float64 y = 0.0;
    float64 * x_hist = x_ptr_;
    for(float64 * b = b_; b < b_ + N_POLES; ++b)
    {
        // When we enter this loop, x_hist is pointing at x[n + 1]
        --x_hist;

        // Bounds check
        if(x_hist < x_history_)
        {
            x_hist = x_end_ptr_ - 1;
        }

        y += *b * *x_hist;
    }

    float64 * y_hist = y_ptr_;
    for(float64 * a = a_ + 1; a < a_ + N_POLES; ++a)
    {
        // When we enter this loop, y_hist is pointing at y[n + 1]
        --y_hist;

        // Bounds check
        if(y_hist < y_history_)
        {
            y_hist = y_end_ptr_ - 1;
        }

        y -= *a * *y_hist;

    }

    // insert output into history buffer
    *y_ptr_ = y;

    // Increment history pointer
    ++y_ptr_;

    // Bounds check
    if(y_ptr_ >= y_end_ptr_)
    {
        y_ptr_ = y_history_;
    }

    return y;
}

float64 FilterParametricEqualizer::filter ( const float64 &  x, const float64 &  frequency  )

virtual

Implements Nsound::Filter.

Definition at line 313 of file FilterParametricEqualizer.cc.

References boost_, filter(), makeKernel(), and resonance_.

{
    makeKernel(frequency, resonance_, boost_);

    return filter(x);
}

float64 FilterParametricEqualizer::filter	(	const float64 &	x,
		const float64 &	frequency,
		const float64 &	resonance
	)

boost is in dB

Definition at line 322 of file FilterParametricEqualizer.cc.

References boost_, filter(), and makeKernel().

{
    makeKernel(frequency, resonance, boost_);

    return filter(x);
}

float64 FilterParametricEqualizer::filter	(	const float64 &	x,
		const float64 &	frequency,
		const float64 &	resonance,
		const float64 &	boost_dB
	)

boost is in dB

Definition at line 334 of file FilterParametricEqualizer.cc.

References filter(), and makeKernel().

{
    makeKernel(frequency, resonance, boost);

    return filter(x);
}

void FilterParametricEqualizer::makeKernel	(	const float64 &	frequency,
		const float64 &	resonance,
		const float64 &	boost
	)

Definition at line 347 of file FilterParametricEqualizer.cc.

References a_, b_, HIGH_SHELF, kernel_cache_, LOW_SHELF, M_PI, N_POLES, PEAKING, Nsound::Filter::sample_rate_, Nsound::Kernel::setA(), Nsound::Kernel::setB(), Nsound::Filter::two_pi_over_sample_rate_, and type_.

Referenced by filter(), and reset().

{
    Kernel new_kernel(N_POLES, N_POLES,
        static_cast<int32>(std::fabs(frequency)),
        static_cast<int32>(resonance * 1e3),
        static_cast<int32>(boost * 1e3));

    // See if the kernel is in the cache.
    KernelCache::iterator itor = kernel_cache_.find(new_kernel);

    // Kernel was found in the cache, set pointers and return.
    if(itor != kernel_cache_.end())
    {
        memcpy(a_, itor->getA(), sizeof(float64) * N_POLES);
        memcpy(b_, itor->getB(), sizeof(float64) * N_POLES);

        return;
    }

    memset(a_, 0, sizeof(float64) * N_POLES);
    memset(b_, 0, sizeof(float64) * N_POLES);

    float64 omega = two_pi_over_sample_rate_ * frequency;

    switch(type_)
    {
        case PEAKING:
        {

//~            K     = tan(omega/2)
//~
//~            b0 =  1 + V*K + K^2
//~            b1 =  2*(K^2 - 1)
//~            b2 =  1 - V*K + K^2
//~
//~            a0 =  1 + K/Q + K^2
//~            a1 =  2*(K^2 - 1)
//~            a2 =  1 - K/Q + K^2

            float64 K = tan(omega / 2.0);
            float64 KK = K * K;
            float64 vkdq = boost * K / resonance;

            b_[0] = 1.0 + vkdq + KK;
            b_[1] = 2.0 * (KK - 1.0);
            b_[2] = 1.0 - vkdq + KK;

            a_[0] = 1.0 + K / resonance + KK;
            a_[1] = b_[1];
            a_[2] = 1.0 - K / resonance + KK;

            break;
        }

        case LOW_SHELF:
        {

//~            K     = tan(omega/2)
//~
//~            b0    = 1 + sqrt(2*V)*K + V*K^2
//~            b1    = 2*(V*K^2 - 1)
//~            b2    = 1 - sqrt(2*V)*K + V*K^2
//~
//~            a0    = 1 + K/Q + K^2
//~            a1    = 2*(K^2 - 1)
//~            a2    = 1 - K/Q + K^2

            float64 omega = 2.0 * M_PI * frequency / sample_rate_;
            float64 K = tan(omega / 2.0);
            float64 KK = K * K;

            float64 sqvk = sqrt(2.0 * boost) * K;
            float64 vkk = boost * KK;

            b_[0] = 1.0 + sqvk + vkk;
            b_[1] = 2.0 * (vkk - 1.0);
            b_[2] = 1.0 - sqvk + vkk;

            a_[0] = 1.0 + K / resonance + KK;
            a_[1] = 2.0 * (KK - 1.0);
            a_[2] = 1.0 - K / resonance + KK;

            break;
        }

        case HIGH_SHELF:
        {

//~            K     = tan((pi-omega)/2)
//~
//~            b0    = 1 + sqrt(2*V)*K + V*K^2
//~            b1    = -2*(V*K^2 - 1)
//~            b1    = 1 - sqrt(2*V)*K + V*K^2
//~
//~            a0    = 1 + K/Q + K^2
//~            a1    = -2*(K^2 - 1)
//~            a2    = 1 - K/Q + K^2

            float64 K = tan((M_PI - omega) * 0.5);
            float64 KK = K * K;
            float64 vkk = boost * KK;

            float64 sq = sqrt(2.0 * boost);

            b_[0] =  1.0 + sq * K + vkk;
            b_[1] = -2.0 * (vkk - 1.0);
            b_[2] =  1.0 - sq * K + vkk;

            a_[0] =  1.0 + K / resonance + KK;
            a_[1] = -2.0 * (KK - 1.0);
            a_[2] =  1.0 - K / resonance + KK;

            break;
        }
    }

    a_[0] = 1.0 / a_[0];

    a_[1] *= a_[0];
    a_[2] *= a_[0];

    b_[0] *= a_[0];
    b_[1] *= a_[0];
    b_[2] *= a_[0];

    new_kernel.setB(b_);
    new_kernel.setA(a_);

    // Add the new kernel to the cache.
    kernel_cache_.insert(new_kernel);
}

void FilterParametricEqualizer::plot	(	boolean	show_fc = true,
		boolean	show_phase = false
	)

Definition at line 485 of file FilterParametricEqualizer.cc.

References Nsound::Plotter::axvline(), frequency_, N_POLES, Nsound::Filter::plot(), Nsound::Filter::sample_rate_, and Nsound::Plotter::title().

{
    Filter::plot(show_phase);

    if(show_fc)
    {
        Plotter pylab;

        pylab.axvline(frequency_,"color='red'");

        char title[128];
        sprintf(title,
            "Parametric Equalizing Frequency Response\n"
            "order = %.0f, f = %0.1f Hz, sr = %0.1f Hz",
            static_cast<float64>(N_POLES - 1),
            frequency_,
            static_cast<float64>(sample_rate_));
        pylab.title(title);
    }
}

void FilterParametricEqualizer::reset ( )

virtual

Implements Nsound::Filter.

Definition at line 508 of file FilterParametricEqualizer.cc.

References boost_, frequency_, makeKernel(), N_POLES, resonance_, x_history_, x_ptr_, y_history_, and y_ptr_.

Referenced by filter(), and FilterParametricEqualizer().

{
    memset(x_history_, 0, sizeof(float64) * (N_POLES + 1));
    memset(y_history_, 0, sizeof(float64) * (N_POLES + 1));

    x_ptr_ = x_history_;
    y_ptr_ = y_history_;

    makeKernel(frequency_, resonance_, boost_);
}

FilterParametricEqualizer& Nsound::FilterParametricEqualizer::operator= ( const FilterParametricEqualizer &  rhs )

private

void Nsound::Filter::setRealtime ( bool  flag )

inlineinherited

Definition at line 57 of file Filter.h.

References Nsound::Filter::is_realtime_.

{is_realtime_ = flag;}

AudioStream Filter::filter ( const AudioStream &  x, const float64 &  frequency  )

inherited

Definition at line 76 of file Filter.cc.

References Nsound::Filter::filter(), Nsound::AudioStream::getNChannels(), Nsound::AudioStream::getSampleRate(), Nsound::Filter::is_realtime_, M_THROW, and Nsound::Filter::reset().

{
    if(!is_realtime_) reset();

    uint32 n_channels = x.getNChannels();

    if(is_realtime_ && n_channels > 1)
    {
        M_THROW("In real-time mode, a filter per audio channel must be used!");
    }

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequency);
    }

    return y;
}

Buffer Filter::filter ( const Buffer &  x, const float64 &  frequency  )

inherited

Definition at line 140 of file Filter.cc.

References Nsound::Buffer::begin(), Nsound::Buffer::end(), Nsound::Filter::filter(), Nsound::Buffer::getLength(), Nsound::Filter::is_realtime_, and Nsound::Filter::reset().

{
    if(!is_realtime_) reset();

    Buffer::const_iterator itor = x.begin();
    Buffer::const_iterator end = x.end();

    Buffer y(x.getLength());

    while(itor != end)
    {
        y << filter(*itor, frequency);

        ++itor;
    }

    return y;
}

Buffer Filter::getFrequencyAxis ( const uint32  n_fft = 8192 )

inherited

Definition at line 185 of file Filter.cc.

References Nsound::FFTransform::roundUp2(), and Nsound::Filter::sample_rate_.

Referenced by main(), Nsound::Filter::plot(), and Nsound::FilterIIR::savePlot().

{
    uint32 fft_chunk_size = FFTransform::roundUp2(
        static_cast<int32>(n_fft));

    uint32 n_samples = fft_chunk_size / 2 + 1;

    float64 f_step = (1.0 / (static_cast<float64>(fft_chunk_size) / 2.0))
                   * (sample_rate_ / 2.0);

    Buffer f_axis;

    float64 f = 0.0;

    for(uint32 i = 0; i < n_samples; ++i)
    {
        f_axis << f;
        f += f_step;
    }

    return f_axis;
};

Buffer Filter::getFrequencyResponse ( const uint32  n_fft = 8192 )

inherited

Definition at line 210 of file Filter.cc.

References Nsound::FFTransform::fft(), Nsound::Filter::getImpulseResponse(), and Nsound::Filter::sample_rate_.

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), FilterLeastSquaresFIR_UnitTest(), Nsound::FilterIIR::getRMS(), main(), Nsound::Filter::plot(), and Nsound::FilterIIR::savePlot().

{
    FFTransform fft(sample_rate_);

//~    fft.setWindow(HANNING);

    FFTChunkVector vec;

    vec = fft.fft(getImpulseResponse(), n_fft);

    return vec[0].getMagnitude();
}

Buffer Filter::getImpulseResponse ( const uint32  n_samples = 8192 )

inherited

Definition at line 225 of file Filter.cc.

References Nsound::Filter::filter(), Nsound::Filter::is_realtime_, and Nsound::Filter::reset().

Referenced by Nsound::Filter::getFrequencyResponse(), Nsound::FilterHighPassFIR::getImpulseResponse(), Nsound::FilterLowPassFIR::getImpulseResponse(), Nsound::FilterLeastSquaresFIR::getImpulseResponse(), Nsound::FilterIIR::getImpulseResponse(), and Nsound::Filter::getPhaseResponse().

{
    if(!is_realtime_) reset();

    Buffer response(n_samples);

    response << filter(1.0);

    for(uint32 i = 1; i < n_samples; ++i)
    {
        response << filter(0.0);
    }

    if(!is_realtime_) reset();

    return response;
}

virtual uint32 Nsound::Filter::getKernelSize ( ) const

inlinevirtualinherited

Reimplemented in Nsound::FilterIIR, and Nsound::FilterTone.

Definition at line 96 of file Filter.h.

References Nsound::Filter::kernel_size_.

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterBandPassIIR::plot(), and Nsound::FilterBandRejectIIR::plot().

{return kernel_size_;};

Buffer Filter::getPhaseResponse ( )

inherited

Definition at line 245 of file Filter.cc.

References Nsound::FFTransform::fft(), Nsound::Filter::getImpulseResponse(), Nsound::Buffer::getLength(), Nsound::Filter::sample_rate_, and Nsound::Buffer::subbuffer().

Referenced by Nsound::Filter::plot().

{
    uint32 n_samples = static_cast<uint32>(sample_rate_ * 2);

    FFTransform fft(n_samples);

    FFTChunkVector vec;

    vec = fft.fft(getImpulseResponse(), n_samples);

    Buffer phase = vec[0].getPhase();

    return phase.subbuffer(0, phase.getLength() / 2 + 1);
}

float64 Nsound::Filter::getSampleRate ( ) const

inlineinherited

Definition at line 102 of file Filter.h.

References Nsound::Filter::sample_rate_.

{ return sample_rate_; };

void Filter::plot ( boolean  show_phase = false )

inherited

Definition at line 262 of file Filter.cc.

References Nsound::Plotter::figure(), Nsound::Buffer::getdB(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Buffer::getMax(), Nsound::Filter::getPhaseResponse(), Nsound::Plotter::plot(), Nsound::Plotter::subplot(), Nsound::Plotter::xlabel(), Nsound::Plotter::ylabel(), and Nsound::Plotter::ylim().

Referenced by main(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterBandPassVocoder::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterBandRejectIIR::plot(), and plot().

{
    Buffer x = getFrequencyAxis();
    Buffer fr = getFrequencyResponse().getdB();

    Plotter pylab;

    pylab.figure();

    uint32 n_rows = 1;
    uint32 n_cols = 1;

    if(show_phase)
    {
        n_rows = 2;
    }

    pylab.subplot(n_rows, n_cols, 1);

    // Frequency response
    pylab.plot(x,fr, "blue");

    pylab.xlabel("Frequency (Hz)");
    pylab.ylabel("Frequency Response (dB)");

    // Phase response
    if(show_phase)
    {
        pylab.subplot(n_rows, n_cols, 2);

        Buffer pr = getPhaseResponse().getdB();

        pylab.plot(x,pr);

        pylab.xlabel("Frequency (Hz)");
        pylab.ylabel("Phase Response (dB)");
    }

    float64 ymax = fr.getMax();
    float64 height = ymax - -60.0;

    pylab.ylim(-60.0, ymax + 0.05 * height);
}

Member Data Documentation

Type Nsound::FilterParametricEqualizer::type_

protected

Definition at line 196 of file FilterParametricEqualizer.h.

Referenced by makeKernel().

float64 Nsound::FilterParametricEqualizer::frequency_

protected

Definition at line 197 of file FilterParametricEqualizer.h.

Referenced by plot(), and reset().

float64 Nsound::FilterParametricEqualizer::resonance_

protected

Definition at line 198 of file FilterParametricEqualizer.h.

Referenced by filter(), and reset().

float64 Nsound::FilterParametricEqualizer::boost_

protected

Definition at line 199 of file FilterParametricEqualizer.h.

Referenced by filter(), and reset().

float64* Nsound::FilterParametricEqualizer::a_

protected

Definition at line 201 of file FilterParametricEqualizer.h.

Referenced by filter(), makeKernel(), and ~FilterParametricEqualizer().

float64* Nsound::FilterParametricEqualizer::b_

protected

Definition at line 202 of file FilterParametricEqualizer.h.

Referenced by filter(), makeKernel(), and ~FilterParametricEqualizer().

float64* Nsound::FilterParametricEqualizer::x_history_

protected

Definition at line 204 of file FilterParametricEqualizer.h.

Referenced by filter(), FilterParametricEqualizer(), reset(), and ~FilterParametricEqualizer().

float64* Nsound::FilterParametricEqualizer::x_ptr_

protected

Definition at line 205 of file FilterParametricEqualizer.h.

Referenced by filter(), FilterParametricEqualizer(), and reset().

float64* Nsound::FilterParametricEqualizer::x_end_ptr_

protected

Definition at line 206 of file FilterParametricEqualizer.h.

Referenced by filter(), and FilterParametricEqualizer().

float64* Nsound::FilterParametricEqualizer::y_history_

protected

Definition at line 208 of file FilterParametricEqualizer.h.

Referenced by filter(), FilterParametricEqualizer(), reset(), and ~FilterParametricEqualizer().

float64* Nsound::FilterParametricEqualizer::y_ptr_

protected

Definition at line 209 of file FilterParametricEqualizer.h.

Referenced by filter(), FilterParametricEqualizer(), and reset().

float64* Nsound::FilterParametricEqualizer::y_end_ptr_

protected

Definition at line 210 of file FilterParametricEqualizer.h.

Referenced by filter(), and FilterParametricEqualizer().

KernelCache Nsound::FilterParametricEqualizer::kernel_cache_

protected

Definition at line 212 of file FilterParametricEqualizer.h.

Referenced by makeKernel().

float64 Nsound::Filter::sample_rate_

protectedinherited

Definition at line 113 of file Filter.h.

Referenced by Nsound::FilterPhaser::filter(), Nsound::FilterCombLowPassFeedback::filter(), Nsound::FilterDelay::filter(), Nsound::FilterAllPass::FilterAllPass(), Nsound::FilterCombLowPassFeedback::FilterCombLowPassFeedback(), Nsound::FilterDelay::FilterDelay(), Nsound::FilterFlanger::FilterFlanger(), Nsound::FilterPhaser::FilterPhaser(), Nsound::FilterSlinky::FilterSlinky(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Filter::getPhaseResponse(), Nsound::Filter::getSampleRate(), Nsound::FilterStageIIR::makeIIRKernelHelper(), Nsound::FilterHighPassFIR::makeKernel(), Nsound::FilterStageIIR::makeKernel(), Nsound::FilterBandPassVocoder::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), makeKernel(), Nsound::FilterPhaser::operator=(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterFlanger::operator=(), Nsound::FilterIIR::operator=(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterBandPassIIR::plot(), plot(), Nsound::FilterLowPassIIR::setCutoff(), and Nsound::FilterLeastSquaresFIR::setWindow().

float64 Nsound::Filter::two_pi_over_sample_rate_

protectedinherited

Definition at line 114 of file Filter.h.

Referenced by Nsound::FilterTone::makeKernel(), Nsound::FilterLowPassFIR::makeKernel(), and makeKernel().

float64 Nsound::Filter::sample_time_

protectedinherited

Definition at line 115 of file Filter.h.

Referenced by Nsound::FilterLowPassMoogVcf::_make_filter().

uint32 Nsound::Filter::kernel_size_

protectedinherited

Definition at line 116 of file Filter.h.

Referenced by Nsound::FilterLowPassFIR::filter(), Nsound::FilterLeastSquaresFIR::filter(), Nsound::FilterBandPassFIR::FilterBandPassFIR(), Nsound::FilterBandPassIIR::FilterBandPassIIR(), Nsound::FilterBandRejectIIR::FilterBandRejectIIR(), Nsound::FilterHighPassIIR::FilterHighPassIIR(), Nsound::FilterLeastSquaresFIR::FilterLeastSquaresFIR(), Nsound::FilterLowPassFIR::FilterLowPassFIR(), Nsound::FilterLowPassIIR::FilterLowPassIIR(), Nsound::FilterLeastSquaresFIR::getKernel(), Nsound::Filter::getKernelSize(), Nsound::FilterHighPassFIR::makeKernel(), Nsound::FilterLowPassFIR::makeKernel(), Nsound::FilterBandRejectFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterLowPassFIR::reset(), Nsound::FilterHighPassFIR::reset(), Nsound::FilterLeastSquaresFIR::reset(), Nsound::FilterLeastSquaresFIR::setKernel(), Nsound::FilterLeastSquaresFIR::setWindow(), and Nsound::FilterHighPassFIR::spectraReversal_().

bool Nsound::Filter::is_realtime_

protectedinherited

Definition at line 118 of file Filter.h.

Referenced by Nsound::Filter::filter(), Nsound::FilterBandRejectIIR::filter(), Nsound::FilterBandRejectFIR::filter(), Nsound::Filter::getImpulseResponse(), and Nsound::Filter::setRealtime().

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

• Nsound/FilterParametricEqualizer.h
• Nsound/FilterParametricEqualizer.cc