diff --git a/effect_modulated_delay.cpp b/effect_modulated_delay.cpp
index c4025c5..26267cd 100644
--- a/effect_modulated_delay.cpp
+++ b/effect_modulated_delay.cpp
@@ -90,7 +90,8 @@ void AudioEffectModulatedDelay::update(void)
     float mod_idx;
     float mod_number;
     float mod_fraction;
-    
+    float modulation_f32[AUDIO_BLOCK_SAMPLES];
+
     bp = block->data;
     arm_q15_to_float(modulation->data, modulation_f32, AUDIO_BLOCK_SAMPLES);
     mp = modulation_f32;
@@ -115,15 +116,15 @@ void AudioEffectModulatedDelay::update(void)
         c_mod_idx += _delay_length;
 
       // linear interpolation
-      if (c_mod_idx < 1)
+      if (c_mod_idx == 0)
       {
         idx[0] = _delay_length - 1;
         idx[1] = 0;
       }
-      else if (c_mod_idx + 1 >= _delay_length)
+      else if (c_mod_idx == _delay_length - 1)
       {
         idx[0] = 0;
-        idx[1] = c_mod_idx;
+        idx[1] = _delay_length - 1;
       }
       else
       {
@@ -131,9 +132,9 @@ void AudioEffectModulatedDelay::update(void)
         idx[1] = c_mod_idx + 1;
       }
       if (mod_idx < 0.0)
-        *bp = round(float(_delayline[idx[0]]) * (1.0 - mod_fraction) + float(_delayline[idx[1]]) * mod_fraction);
+        *bp = round(float(_delayline[idx[0]]) * fabs(mod_fraction) + float(_delayline[idx[1]]) * (1.0 - fabs(mod_fraction)));
       else
-        *bp = round(float(_delayline[idx[0]]) * mod_fraction + float(_delayline[idx[1]]) * (1.0 - mod_fraction));
+        *bp = round(float(_delayline[idx[0]]) * (1.0 - mod_fraction) + float(_delayline[idx[1]]) * mod_fraction);
 
       // push the pointers forward
       bp++; // next audio data
diff --git a/effect_modulated_delay.h b/effect_modulated_delay.h
index 03c243f..cce71e8 100644
--- a/effect_modulated_delay.h
+++ b/effect_modulated_delay.h
@@ -60,7 +60,6 @@ class AudioEffectModulatedDelay :
     arm_biquad_casd_df1_inst_f32 filter_lp_mod;
     float filter_lp_state[4];
     float filter_lp_coeffs[5];
-    float modulation_f32[AUDIO_BLOCK_SAMPLES];
 #endif
 
 };