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Merge pull request #1456 from diizy/crossovereq

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LR filter -> direct form 2
This commit is contained in:
Vesa V
2014-12-17 00:59:10 +02:00
parent fa86a2cdac 8402bcb525
commit 28ec70decd
1 changed files with 4 additions and 24 deletions
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28
include/BasicFilters.h
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@@ -64,7 +64,6 @@ public:
for( int i = 0; i < CHANNELS; ++i )
{
m_z1[i] = m_z2[i] = m_z3[i] = m_z4[i] = 0.0f;
m_y1[i] = m_y2[i] = m_y3[i] = m_y4[i] = 0.0f;
}
}
@@ -119,34 +118,16 @@ public:
inline float update( float in, ch_cnt_t ch )
{
const double y = m_a0 * in + ( m_z1[ch] * m_a1 ) + ( m_z2[ch] * m_a2 ) +
( m_z3[ch] * m_a1 ) + ( m_z4[ch] * m_a0 ) -
( m_y1[ch] * m_b1 ) - ( m_y2[ch] * m_b2 ) -
( m_y3[ch] * m_b3 ) - ( m_y4[ch] * m_b4 );
m_z4[ch] = m_z3[ch];
m_z3[ch] = m_z2[ch];
m_z2[ch] = m_z1[ch];
m_z1[ch] = in;
m_y4[ch] = m_y3[ch];
m_y3[ch] = m_y2[ch];
m_y2[ch] = m_y1[ch];
m_y1[ch] = y;
return y;
// for some reason converting to direct form 2 doesn't seem to work for this filter
/* const double x = in - ( m_z1[ch] * m_b1 ) - ( m_z2[ch] * m_b2 ) -
const double x = in - ( m_z1[ch] * m_b1 ) - ( m_z2[ch] * m_b2 ) -
( m_z3[ch] * m_b3 ) - ( m_z4[ch] * m_b4 );
const double y = ( m_a0 * x ) + ( m_z1[ch] * m_a1 ) + ( m_z2[ch] * m_a2 ) +
( m_z3[ch] * m_a1 ) + ( m_z4[ch] * m_a0 );
m_z4[ch] = m_z3[ch];
m_z3[ch] = m_z2[ch];
m_z2[ch] = m_z1[ch];
m_z1[ch] = x;
return ( m_a0 * x ) + ( m_z1[ch] * m_a1 ) + ( m_z2[ch] * m_a2 ) +
( m_z3[ch] * m_a1 ) + ( m_z4[ch] * m_a0 );*/
return y;
}
private:
@@ -158,7 +139,6 @@ private:
typedef double frame[CHANNELS];
frame m_z1, m_z2, m_z3, m_z4;
frame m_y1, m_y2, m_y3, m_y4;
};
typedef LinkwitzRiley<2> StereoLinkwitzRiley;