wip use svf as main filter

magnetophon · Dec 23, 2024 · bbd3b58 · bbd3b58
1 parent 746307c
commit bbd3b58
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Showing 3 changed files with 23 additions and 10 deletions.
diff --git a/src/delay_tap.rs b/src/delay_tap.rs
@@ -14,6 +14,7 @@ pub struct DelayTap {
 
     pub filter_params: Arc<FilterParams>,
     pub ladders: LadderFilter,
+    pub lowpass: SVFSimper<4>,
     pub shelving_eq: SVFSimper<4>,
     pub mute_in_delayed: Box<[bool]>,
     /// Fades between 0 and 1 with timings based on the global attack and release settings.
@@ -57,6 +58,7 @@ impl DelayTap {
             delayed_audio_r: vec![0.0; MAX_BLOCK_SIZE].into_boxed_slice(),
             filter_params: filter_params.clone(),
             ladders: LadderFilter::new(filter_params),
+            lowpass: SVFSimper::new(440.0, 0.5, 48000.0),
             shelving_eq: SVFSimper::new(PANNER_EQ_FREQ, PANNER_EQ_RES, 48000.0),
             mute_in_delayed: vec![false; MAX_BLOCK_SIZE].into_boxed_slice(),
             amp_envelope: Smoother::new(SmoothingStyle::Linear(13.0)),

diff --git a/src/lib.rs b/src/lib.rs
@@ -639,6 +639,7 @@ impl Plugin for Del2 {
         // Initialize filter parameters for each tap
         self.initialize_filter_parameters();
         for delay_tap in &mut self.delay_taps {
+            delay_tap.lowpass.reset(440.0, 0.5, sample_rate);
             delay_tap
                 .shelving_eq
                 .reset(PANNER_EQ_FREQ, PANNER_EQ_RES, sample_rate);
@@ -655,7 +656,6 @@ impl Plugin for Del2 {
             delay_tap.amp_envelope.reset(0.0);
             delay_tap.ladders.s = [f32x4::splat(0.); 4];
         });
-
         self.drive_main_smoother.reset(0.0);
         // then fill the array
         for tap_index in 0..tap_counter {
@@ -956,6 +956,12 @@ impl Plugin for Del2 {
                                         + value_idx as f32,
                                 ) * pre_filter_gain;
                         }
+
+                        // TODO: smooth
+                        let cutoff = taps_params.cutoff_main.value();
+                        let res = taps_params.res_main.value();
+                        delay_tap.lowpass.set(cutoff, res * 2.0);
+
                         // HQ mode:
                         for i in block_start..block_end {
                             let frame = f32x4::from_array([
@@ -972,8 +978,10 @@ impl Plugin for Del2 {
                                 0.0,
                             ]);
 
-                            let frame_filtered = *delay_tap.ladders.tick_pivotal(frame).as_array();
+                            // let frame_filtered = *delay_tap.ladders.tick_pivotal(frame).as_array();
                             // let frame_filtered = *delay_tap.ladders.tick_linear(frame).as_array();
+                            let frame_filtered = delay_tap.lowpass.lowpass(frame);
+                            // let frame_filtered = delay_tap.lowpass.bandpass(frame);
                             let frame_out = delay_tap
                                 .shelving_eq
                                 .highshelf_cheap(frame_filtered.into(), gain_values);

diff --git a/src/svf_simper.rs b/src/svf_simper.rs
@@ -94,7 +94,9 @@ where
     #[inline]
     fn compute_parameters(cutoff: f32, resonance: f32, pi_over_sr: f32) -> (f32, f32, f32, f32) {
         let g = (cutoff * pi_over_sr).tan();
-        let k = 2.0 * (1.0 - resonance.clamp(0.0, 1.0));
+        // let k = 2.0 * (1.0 - resonance.clamp(0.0, 1.0));
+        // let k = (2.0 * (1.0 - resonance)).min(2.0);
+        let k = 2.0 * (1.0 - resonance);
         let a1 = g.mul_add(g + k, 1.0).recip();
         let a2 = g * a1;
         let a3 = g * a2;
@@ -108,9 +110,8 @@ where
     #[inline]
     pub fn fast_tanh(v: Simd<f32, LANES>) -> Simd<f32, LANES> {
         let square = v * v; // Element-wise squaring
-        v * (Simd::splat(25.95) + square)
-            / (Simd::splat(26.369) + Simd::splat(8.78) * square)
-                .simd_clamp(Simd::splat(-1.0), Simd::splat(1.0))
+        (v * (Simd::splat(25.95) + square) / (Simd::splat(26.369) + Simd::splat(8.78) * square))
+            .simd_clamp(Simd::splat(-1.0), Simd::splat(1.0))
     }
 
     // quickerTanh / quickerTanh64 credits to mopo synthesis library:
@@ -126,11 +127,13 @@ where
     #[inline]
     fn process(&mut self, v0: Simd<f32, LANES>) -> (Simd<f32, LANES>, Simd<f32, LANES>) {
         let v3 = v0 - self.ic2eq;
-        let v1 = Self::fast_tanh((self.a1 * self.ic1eq) + (self.a2 * v3));
+        let v1 = (self.a1 * self.ic1eq) + (self.a2 * v3);
         let v2 = self.ic2eq + (self.a2 * self.ic1eq) + (self.a3 * v3);
 
-        self.ic1eq = (Simd::splat(2.0) * v1) - self.ic1eq;
-        self.ic2eq = (Simd::splat(2.0) * v2) - self.ic2eq;
+        // self.ic1eq = (Simd::splat(2.0) * v1) - self.ic1eq;
+        self.ic1eq = Self::fast_tanh((Simd::splat(2.0) * v1) - self.ic1eq);
+        // self.ic2eq = (Simd::splat(2.0) * v2) - self.ic2eq;
+        self.ic2eq = Self::fast_tanh((Simd::splat(2.0) * v2) - self.ic2eq);
 
         (v1, v2)
     }
@@ -190,7 +193,7 @@ where
         v0: Simd<f32, LANES>,
         lin_gain: Simd<f32, LANES>,
     ) -> Simd<f32, LANES> {
-        let (v1, v2) = self.process(v0);
+        let (_, v2) = self.process(v0);
         lin_gain.mul_add(v2, v0 - v2)
     }
     #[inline]