bug fix: direct piezo hits sometimes cause a MIDI mute #142

edrumulus.cpp

@@ -582,11 +582,18 @@ void Edrumulus::Pad::initialize()
   x_low_hist_len        = x_sq_hist_len + lp_filt_len;
 
   // clipping compensation initialization
-  for ( int i = 0; i < length_ampmap; i++ )
+  length_ampmap = 0;
+  for ( int i = 0; i < max_length_ampmap; i++ )
   {
-    // never to higher than 5
-    amplification_mapping[i] = min ( 5.0f, pow ( 10.0f, ( i * pad_settings.clip_comp_ampmap_step ) *
-                                                        ( i * pad_settings.clip_comp_ampmap_step ) ) );
+    const float amp_map_val = pow ( 10.0f, ( i * pad_settings.clip_comp_ampmap_step ) *
+                                           ( i * pad_settings.clip_comp_ampmap_step ) );
+
+    // never to higher than 5 but at least two values
+    if ( ( length_ampmap < 2 ) || ( amp_map_val <= 5.0f ) )
+    {
+      amplification_mapping[i] = amp_map_val;
+      length_ampmap++;
+    }
   }
 
   // pre-calculate equations needed for 3 sensor get position function
@@ -996,7 +1003,7 @@ float Edrumulus::Pad::process_sample ( const float* input,
             mean_neighbor = sqrt ( right_neighbor ); // only right neighbor available
           }
 
-          const float a_low                      = amplification_mapping[min ( length_ampmap - 1, number_overloaded_samples )];
+          const float a_low                      = amplification_mapping[min ( length_ampmap - 2, number_overloaded_samples )];
           const float a_high                     = amplification_mapping[min ( length_ampmap - 1, number_overloaded_samples + 1 )];
           const float a_diff                     = a_high - a_low;
           const float a_diff_abs                 = a_diff * peak_val_sqrt / a_low;

edrumulus.h

@@ -342,7 +342,7 @@ class Edrumulus
       void initialize(); // this function should not be called directly but use sched_init() instead
       void sched_init() { init_delay_cnt = init_delay_value; }; // schedule initialization function (for delayed initialization)
       const float      init_delay_value_s = 0.2; // init delay value in seconds
-      static const int length_ampmap      = 20;  // maxmimum number of amplification mappings for clipping compensation
+      static const int max_length_ampmap  = 20;  // maxmimum number of amplification mappings for clipping compensation
       static const int ctrl_history_len   = 10;  // (MUST BE AN EVEN VALUE) control history length; the longer, the more noise reduction but more delay
 
       // band-pass filter coefficients (they are constant and must not be changed)
@@ -430,7 +430,8 @@ const float ADC_noise_peak_velocity_scaling = 1.0f / 6.0f;
       int          init_delay_value;
       int          overload_hist_len;
       int          max_num_overloads;
-      float        amplification_mapping[length_ampmap];
+      int          length_ampmap;
+      float        amplification_mapping[max_length_ampmap];
       int          scan_time;
       int          pre_scan_time;
       int          total_scan_time;