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This commit is contained in:
Vesa
2014-11-13 18:10:53 +02:00
parent 16fb09fb94
commit bb821d685b
2 changed files with 69 additions and 38 deletions
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105
include/basic_filters.h
View File

@@ -72,6 +72,8 @@ public:
Lowpass_SV,
Bandpass_SV,
Highpass_SV,
Notch_SV,
FastFormant,
NumFilters
} ;
@@ -202,21 +204,26 @@ public:
}
// 4-pole state-variant lowpass filter, adapted from Nekobee source code
// and extended to other SV filter types
// /* Hal Chamberlin's state variable filter */
case Lowpass_SV:
case Bandpass_SV:
{
m_sva[_chnl] += ( qAbs( _in0 ) - m_sva[_chnl] ) * m_svsr;
float highpass;
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl]; /* delay2/4 = lowpass output */
float highpass = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * highpass + m_delay1[_chnl]; /* delay1/3 = bandpass output */
for( int i = 0; i < 2; ++i ) // 2x oversample
{
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl]; /* delay2/4 = lowpass output */
highpass = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * highpass + m_delay1[_chnl]; /* delay1/3 = bandpass output */
m_delay4[_chnl] = m_delay4[_chnl] + m_svf2 * m_delay3[_chnl];
highpass = m_delay2[_chnl] - m_delay4[_chnl] - m_svq * m_delay3[_chnl];
m_delay3[_chnl] = m_svf2 * highpass + m_delay3[_chnl];
}
m_delay4[_chnl] = m_delay4[_chnl] + m_svf2 * m_delay3[_chnl];
highpass = m_delay2[_chnl] - m_delay4[_chnl] - m_svq * m_delay3[_chnl];
m_delay3[_chnl] = m_svf2 * highpass + m_delay3[_chnl];
/* mix filter output into output buffer */
out = m_type == Lowpass_SV
? atanf( 3.0f * m_delay4[_chnl] * m_sva[_chnl] )
@@ -227,14 +234,39 @@ public:
case Highpass_SV:
{
m_sva[_chnl] += ( qAbs( _in0 ) - m_sva[_chnl] ) * m_svsr;
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl];
float hp = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * hp + m_delay1[_chnl];
float hp;
for( int i = 0; i < 2; ++i ) // 2x oversample
{
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl];
hp = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * hp + m_delay1[_chnl];
}
out = atanf( 3.0f * hp * m_sva[_chnl] );
break;
}
case Notch_SV:
{
m_sva[_chnl] += ( qAbs( _in0 ) - m_sva[_chnl] ) * m_svsr;
float hp1, hp2;
for( int i = 0; i < 2; ++i ) // 2x oversample
{
m_delay2[_chnl] = m_delay2[_chnl] + m_svf1 * m_delay1[_chnl]; /* delay2/4 = lowpass output */
hp1 = _in0 - m_delay2[_chnl] - m_svq * m_delay1[_chnl];
m_delay1[_chnl] = m_svf1 * hp1 + m_delay1[_chnl]; /* delay1/3 = bandpass output */
m_delay4[_chnl] = m_delay4[_chnl] + m_svf2 * m_delay3[_chnl];
hp2 = m_delay2[_chnl] - m_delay4[_chnl] - m_svq * m_delay3[_chnl];
m_delay3[_chnl] = m_svf2 * hp2 + m_delay3[_chnl];
}
/* mix filter output into output buffer */
out = atanf( 1.5f * ( m_delay4[_chnl] + hp2 ) * m_sva[_chnl] );
break;
}
// 4-times oversampled simulation of an active RC-Bandpass,-Lowpass,-Highpass-
@@ -376,11 +408,13 @@ public:
}
case Formantfilter:
case FastFormant:
{
sample_t hp, bp, in;
out = 0;
for(int o=0; o<4; o++)
const int os = m_type == FastFormant ? 1 : 4; // no oversampling for fast formant
for( int o = 0; o < os; ++o )
{
// first formant
in = _in0 + m_vfbp[0][_chnl] * m_vfq;
@@ -466,7 +500,7 @@ public:
out += bp;
}
return( out/2.0f );
return( out * 0.5f );
break;
}
@@ -511,16 +545,17 @@ public:
{
_freq = qBound( 50.0f, _freq, 20000.0f );
m_rca = 1.0f - (1.0f/(m_sampleRate*4)) / ( (1.0f/(_freq*2.0f*M_PI)) + (1.0f/(m_sampleRate*4)) );
m_rca = 1.0f - (1.0f/(m_sampleRate*4)) / ( (1.0f/(_freq*2.0f*F_PI)) + (1.0f/(m_sampleRate*4)) );
m_rcb = 1.0f - m_rca;
m_rcc = (1.0f/(_freq*2.0f*M_PI)) / ( (1.0f/(_freq*2.0f*M_PI)) + (1.0f/(m_sampleRate*4)) );
m_rcc = (1.0f/(_freq*2.0f*F_PI)) / ( (1.0f/(_freq*2.0f*F_PI)) + (1.0f/(m_sampleRate*4)) );
// Stretch Q/resonance, as self-oscillation reliably starts at a q of ~2.5 - ~2.6
m_rcq = _q * 0.25f;
return;
}
if( m_type == Formantfilter )
if( m_type == Formantfilter ||
m_type == FastFormant )
{
_freq = qBound( minFreq(), _freq, 20000.0f ); // limit freq and q for not getting bad noise out of the filter...
@@ -543,21 +578,19 @@ public:
const float f0 = linearInterpolate( _f[vowel+0][0], _f[vowel+1][0], fract );
const float f1 = linearInterpolate( _f[vowel+0][1], _f[vowel+1][1], fract );
m_vfa[0] = 1.0f - (1.0f/(m_sampleRate*4)) /
( (1.0f/(f0*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
m_vfb[0] = 1.0f - m_vfa[0];
m_vfc[0] = (1.0f/(f0*2.0f*M_PI)) /
( (1.0f/(f0*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
// samplerate coeff: depends on oversampling
const float sr = m_type == FastFormant ? m_sampleRatio : m_sampleRatio * 0.25f;
m_vfa[1] = 1.0f - (1.0f/(m_sampleRate*4)) /
( (1.0f/(f1*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
m_vfa[0] = 1.0f - sr /
( ( 1.0f / ( f0 * 2.0f * F_PI ) ) + sr );
m_vfb[0] = 1.0f - m_vfa[0];
m_vfc[0] = ( 1.0f / ( f0 * 2.0f * F_PI ) ) /
( ( 1.0f / ( f0 *2.0f * F_PI ) ) + sr );
m_vfa[1] = 1.0f - sr /
( ( 1.0f / ( f1 * 2.0f * F_PI ) ) + sr );
m_vfb[1] = 1.0f - m_vfa[1];
m_vfc[1] = (1.0f/(f1*2.0f*M_PI)) /
( (1.0f/(f1*2.0f*M_PI)) +
(1.0f/(m_sampleRate*4)) );
m_vfc[1] = ( 1.0f / ( f1 * 2.0f * F_PI ) ) /
( ( 1.0f / ( f1 * 2.0f * F_PI ) ) + sr );
return;
}
@@ -584,11 +617,12 @@ public:
if( m_type == Lowpass_SV ||
m_type == Bandpass_SV ||
m_type == Highpass_SV )
m_type == Highpass_SV ||
m_type == Notch_SV )
{
const float f = qMax( minFreq(), _freq ) * m_sampleRatio;
m_svf1 = qMin( f * 2.0f, 0.825f );
m_svf2 = qMin( f * 4.0f, 0.825f );
const float f = sinf( qMax( minFreq(), _freq ) * m_sampleRatio * F_PI );
m_svf1 = qMin( f, 0.825f );
m_svf2 = qMin( f * 2.0f, 0.825f );
m_svq = qMax( 0.0001f, 2.0f - ( _q * 0.1995f ) );
return;
}
@@ -598,12 +632,7 @@ public:
const float omega = F_2PI * _freq * m_sampleRatio;
const float tsin = sinf( omega );
const float tcos = cosf( omega );
//float alpha;
//if (q_is_bandwidth)
//alpha = tsin*sinhf(logf(2.0f)/2.0f*q*omega/
// tsin);
//else
const float alpha = 0.5f * tsin / _q;
const float a0 = 1.0f / ( 1.0f + alpha );

2
src/core/InstrumentSoundShaping.cpp
View File

@@ -98,6 +98,8 @@ InstrumentSoundShaping::InstrumentSoundShaping(
m_filterModel.addItem( tr( "SV LowPass" ), new PixmapLoader( "filter_lp" ) );
m_filterModel.addItem( tr( "SV BandPass" ), new PixmapLoader( "filter_bp" ) );
m_filterModel.addItem( tr( "SV HighPass" ), new PixmapLoader( "filter_hp" ) );
m_filterModel.addItem( tr( "SV Notch" ), new PixmapLoader( "filter_notch" ) );
m_filterModel.addItem( tr( "Fast Formant" ), new PixmapLoader( "filter_hp" ) );
}