diff --git a/protosynth/protosynth_dependencies/saike_proto_synth_fx.jsfx-inc b/protosynth/protosynth_dependencies/saike_proto_synth_fx.jsfx-inc
index bddb268..b9440f6 100644
--- a/protosynth/protosynth_dependencies/saike_proto_synth_fx.jsfx-inc
+++ b/protosynth/protosynth_dependencies/saike_proto_synth_fx.jsfx-inc
@@ -215,18 +215,18 @@ global(
 );
 
 
-function freq_shift_audio_rate(in, shift)
+function freq_shift_audio_rate(in, shift, fb)
 instance(
-  fs_l1, fs_r1, fs_l2, fs_r2,
+  fs_l1, fs_r1, fs_l2, fs_r2, ly,
   dt2, t2,
 )
 local(ct2, st2)
 global(tpiT, fs.ct1, fs.st1)
 (
-  t2 += 1.5771 + tpiT * shift; // oscillating at srate / 4 (2.0 * $pi * 0.251)
+  t2 += 1.5771 + tpiT * (shift + fb * ly); // oscillating at srate / 4 (2.0 * $pi * 0.251)
   (t2 > 628.32) ? t2 -= 628.32; // 200 * $pi;
   
-  fs_l1.quick_ellip(in * fs.ct1) * cos(t2) + fs_l2.quick_ellip(in * fs.st1) * sin(t2)
+  ly = fs_l1.quick_ellip(in * fs.ct1) * cos(t2) + fs_l2.quick_ellip(in * fs.st1) * sin(t2)
 );
 
 function poisson_noise(in_left, in_right, freq, polarity)
@@ -278,7 +278,7 @@ instance(lpf, lpf2, lpf3, lpf4, lpf5)
 <?
   function input(sample2)
   (
-    printf("this.buf1.read_cheapo(fm_offset + (max(-fm_offset, fm_factor * %s)))", sample2);
+    printf("this.buf1.read_cheapo(fm_offset + (max(-fm_offset, fm_factor * (%s))))", sample2);
   );
   
   function input2(sample2, sample3)
@@ -292,7 +292,7 @@ instance(lpf, lpf2, lpf3, lpf4, lpf5)
   );
 ?>
 
-function process_phasemod(x1, x2, ifreq)
+function process_phasemod(x1, x2, ifreq, feedback)
 local(y, y1, y2, y3, fm_factor)
 global(osc_feedback1, fm_offset, fm_scaling)
 instance(last_x1, last_x2, write_ptr, lpf, lpf2, y4)
@@ -302,14 +302,15 @@ instance(last_x1, last_x2, write_ptr, lpf, lpf2, y4)
   
   fm_factor = fm_scaling * ifreq;
   
-  y1 = <?input("this.buf2.read_cheapo(fm_offset + 1) + osc_feedback1 * y4")?>;
-  y2 = <?input("this.buf2.read_cheapo(fm_offset + 0.75) + osc_feedback1 * y1")?>;
-  y3 = <?input("this.buf2.read_cheapo(fm_offset + 0.5) + osc_feedback1 * y2")?>;
-  y4 = <?input("this.buf2.read_cheapo(fm_offset + 0.25) + osc_feedback1 * y3")?>;
+  y1 = <?input("this.buf2.read_cheapo(fm_offset + 1) + feedback * y4")?>;
+  y2 = <?input("this.buf2.read_cheapo(fm_offset + 0.75) + feedback * y1")?>;
+  y3 = <?input("this.buf2.read_cheapo(fm_offset + 0.5) + feedback * y2")?>;
+  y4 = <?input("this.buf2.read_cheapo(fm_offset + 0.25) + feedback * y3")?>;
   
   this.elliptic_4x(y1);
   this.elliptic_4x(y2);
   this.elliptic_4x(y3);
+  this.elliptic_4x(y3);
   y = this.elliptic_4x(y4);
     
   last_x1 = x1;
@@ -318,9 +319,9 @@ instance(last_x1, last_x2, write_ptr, lpf, lpf2, y4)
   y
 );
 
-function process_phasemod2(x1, x2, ifreq)
+function process_phasemod2(x1, x2, ifreq, feedback)
 local(y, fm_factor, xx2, y1, y2, y3)
-global(osc_feedback1, fm_offset, fm_scaling)
+global(fm_offset, fm_scaling)
 instance(last_x1, last_x2, write_ptr, lpf, lpf2, lifreq, y4)
 (
   this.buf1.write_simple_buffer(x1);
@@ -328,10 +329,10 @@ instance(last_x1, last_x2, write_ptr, lpf, lpf2, lifreq, y4)
   
   xx2 = lpf2.eval_linearSVF_LP(lpf.eval_linearSVF_LP(x2));
   
-  y1 = <?input2("last_x2", "osc_feedback1 * y4")?>;
-  y2 = <?input2("last_x2 * 0.75 + xx2 * 0.25", "osc_feedback1 * y1")?>;
-  y3 = <?input2("last_x2 * 0.5 + xx2 * 0.5", "osc_feedback1 * y2")?>;
-  y4 = <?input2("last_x2 * 0.25 + xx2 * 0.75", "osc_feedback1 * y3")?>;
+  y1 = <?input2("last_x2", "feedback * y4")?>;
+  y2 = <?input2("last_x2 * 0.75 + xx2 * 0.25", "feedback * y1")?>;
+  y3 = <?input2("last_x2 * 0.5 + xx2 * 0.5", "feedback * y2")?>;
+  y4 = <?input2("last_x2 * 0.25 + xx2 * 0.75", "feedback * y3")?>;
   
   this.elliptic_4x(y1);
   this.elliptic_4x(y2);
@@ -344,7 +345,7 @@ instance(last_x1, last_x2, write_ptr, lpf, lpf2, lifreq, y4)
   y
 );
 
-function process_phasemod3(x1, x2, ifreq)
+function process_phasemod3(x1, x2, ifreq, feedback)
 local(y, fm_factor, xx2, y1, y2, y3)
 global(osc_feedback1, fm_offset, fm_scaling)
 instance(last_x1, last_x2, write_ptr, lpf, lpf2, lifreq, y4)
@@ -354,10 +355,10 @@ instance(last_x1, last_x2, write_ptr, lpf, lpf2, lifreq, y4)
   
   xx2 = lpf2.eval_linearSVF_LP(lpf.eval_linearSVF_LP(x2));
   
-  y1 = <?input3("last_x2", "osc_feedback1 * y4")?>;
-  y2 = <?input3("last_x2 * 0.75 + xx2 * 0.25", "osc_feedback1 * y1")?>;
-  y3 = <?input3("last_x2 * 0.5 + xx2 * 0.5", "osc_feedback1 * y2")?>;
-  y4 = <?input3("last_x2 * 0.25 + xx2 * 0.75", "osc_feedback1 * y3")?>;
+  y1 = <?input3("last_x2", "feedback * y4")?>;
+  y2 = <?input3("last_x2 * 0.75 + xx2 * 0.25", "feedback * y1")?>;
+  y3 = <?input3("last_x2 * 0.5 + xx2 * 0.5", "feedback * y2")?>;
+  y4 = <?input3("last_x2 * 0.25 + xx2 * 0.75", "feedback * y3")?>;
   
   this.elliptic_4x(y1);
   this.elliptic_4x(y2);
diff --git a/protosynth/protosynth_dependencies/saike_proto_synth_pixel_gfx.jsfx-inc b/protosynth/protosynth_dependencies/saike_proto_synth_pixel_gfx.jsfx-inc
index 5e22f93..9cc7d93 100644
--- a/protosynth/protosynth_dependencies/saike_proto_synth_pixel_gfx.jsfx-inc
+++ b/protosynth/protosynth_dependencies/saike_proto_synth_pixel_gfx.jsfx-inc
@@ -683,6 +683,7 @@ instance(
   change_amount_modulated,
   display_value,
   _me,
+  bidi_slider,
 )
 global(
   x_offset, y_offset, blit_scale,
@@ -748,16 +749,26 @@ global(
     cap_mode = me;
   );
   
-  ix = x + 2;
-  loop(floor(0.5 * (w - 3)),
-    (ix - x) <= floor(x_norm * w) ? (
-      colormodel(color);
-      active ? (gfx_a = 0.6) : (gfx_a = 0.2)
+  bidi_slider ? (
+    ix = x + 2;
+    colormodel(color);
+    (x_norm > 0.5) ? (
+      gfx_rect(x + 0.5 * w, y + 2, 0.5 * x_norm * w - 2, 1);
     ) : (
-      gfx_set(0, 0, 0, 0.2);
+      gfx_rect(x + x_norm * w + 2, y + 2, floor((0.5 - x_norm) * w - 0.0001), 1);
+    );
+  ) : (
+    ix = x + 2;
+    loop(floor(0.5 * (w - 3)),
+      (ix - x) <= floor(x_norm * w) ? (
+        colormodel(color);
+        active ? (gfx_a = 0.6) : (gfx_a = 0.2)
+      ) : (
+        gfx_set(0, 0, 0, 0.2);
+      );
+      gfx_line(ix, y + 2, ix, y + h - 3);
+      ix += 2;
     );
-    gfx_line(ix, y + 2, ix, y + h - 3);
-    ix += 2;
   );
   
   ((cap_mode == me) || change_amount_modulated) ? (
diff --git a/protosynth/saike_protosynth.jsfx b/protosynth/saike_protosynth.jsfx
index d40df0c..dbc2f98 100644
--- a/protosynth/saike_protosynth.jsfx
+++ b/protosynth/saike_protosynth.jsfx
@@ -99,6 +99,15 @@ slider163:f4_keyfollow=0<0,1,0.00001>-Output Key follow
     par += 1; i += 1;
   );
 ?>
+
+slider239:fb1=0<-0.999,0.999,.0001>-fb1
+slider240:fb2=0<-0.999,0.999,.0001>-fb2
+slider241:fb3=0<-0.999,0.999,.0001>-fb3
+slider242:fb4=0<-0.999,0.999,.0001>-fb4
+slider243:fb21=0<-0.999,0.999,.0001>-fb21
+slider244:fb22=0<-0.999,0.999,.0001>-fb22
+slider245:fb31=0<-0.999,0.999,.0001>-fb31
+
 slider246:glide_time=100<3,3000,0.001:log>-glide time
 slider247:poisson_freq=500<20, 10000, 0.01:log>-poisson_freq
 
@@ -241,6 +250,14 @@ poisson_slider.init_slider_ui(247, 20, 10000, 1);
 time_slider.init_slider_ui(248, 5, 2800, 1);
 verb_mix_slider.init_slider_ui(249, 0, 1, 0);
 
+<?
+  i = 0;
+  loop(7,
+    printf("f_fb_slider%d.init_slider_ui(%d, -0.999, 0.999, 0);", i, 239 + i);
+    printf("f_fb_slider%d.bidi_slider = 1;", i);
+    i += 1;
+  );
+?>
 <?
   par2 = 164;
   loop(i=0;8,
@@ -758,6 +775,7 @@ global(
   mix_mode1, mix_mode2, mix_mode3, mix_mode4,
   mix_mode21, mix_mode22,
   mix_mode31,
+  fb1, fb2, fb3, fb4, fb21, fb22, fb31,
   filter1_enabled, filter2_enabled, filter3_enabled,
   current_f3_gain,
   <?loop(i=1;N_OSCS, printf("osc%d_enabled, ", i); i += 1; );?>
@@ -781,10 +799,10 @@ instance(
         : (mix_mode%d == 3) ? (min(max(o%d, o%d), min(o%d, o%d))) 
         : (mix_mode%d == 4) ? (t1 = o%d + o%d; t2 = o%d - o%d; min(max(t1, t2), -min(t1, t2))) 
         : (mix_mode%d == 5) ? (mix%d.process_stft_mixer(o%d, o%d); mix%d.out_left)
-        : (mix_mode%d == 6) ? (this.ofs%d.freq_shift_audio_rate(o%d, 16 * this.freq * o%d))
-        : (mix_mode%d == 7) ? (mix%d.process_phasemod(o%d, o%d, osc%d.current_ifreq))
-        : (mix_mode%d == 8) ? (mix%d.process_phasemod2(o%d, o%d, osc%d.current_ifreq))
-        : (mix_mode%d == 9) ? (mix%d.process_phasemod3(o%d, o%d, osc%d.current_ifreq));
+        : (mix_mode%d == 6) ? (this.ofs%d.freq_shift_audio_rate(o%d, 16 * this.freq * o%d, this.freq * fb%d))
+        : (mix_mode%d == 7) ? (mix%d.process_phasemod(o%d, o%d, osc%d.current_ifreq, fb%d))
+        : (mix_mode%d == 8) ? (mix%d.process_phasemod2(o%d, o%d, osc%d.current_ifreq, fb%d))
+        : (mix_mode%d == 9) ? (mix%d.process_phasemod3(o%d, o%d, osc%d.current_ifreq, fb%d));
         ",
         mix_out, 
         mix_id, o1, o2, 
@@ -793,10 +811,10 @@ instance(
         mix_id, o1, o2, o1, o2, 
         mix_id, o1, o2, o1, o2,
         mix_id, mix_id, o1, o2, mix_id,
-        mix_id, mix_id, o1, o2,
-        mix_id, mix_id, o1, o2, o1,
-        mix_id, mix_id, o1, o2, o1,
-        mix_id, mix_id, o1, o2, o1
+        mix_id, mix_id, o1, o2, mix_id,
+        mix_id, mix_id, o1, o2, o1, mix_id,
+        mix_id, mix_id, o1, o2, o1, mix_id,
+        mix_id, mix_id, o1, o2, o1, mix_id
       );
     );
   ?>
@@ -1026,7 +1044,7 @@ verb.reset_verb();
 midi.reset_midi();
 <?loop(i=0;MAX_VOICES, printf("v%d.process_midi(i, 0, 0, 0, -1, 0);", i, i); i += 1);?>
 
-CURRENT_VERSION = 11;
+CURRENT_VERSION = 12;
 version = CURRENT_VERSION;
 
 @serialize
@@ -1174,6 +1192,10 @@ f_morph_slider4.serialize_if(version, 8);
   reverb_algorithm = 0;
 );
 
+(version < 12) ? (
+  fb1 = fb2 = fb3 = fb4 = fb21 = fb22 = fb31 = 0;
+);
+
 version = CURRENT_VERSION;
 
 @slider
@@ -1788,6 +1810,8 @@ global(gfx_a, gfx_x, gfx_y, mouse_x, mouse_y, x_offset, y_offset, blit_scale, ca
       );
     );
   );
+  
+  
 );
 
 function cline(x1, y1, x2, y2)
@@ -1807,18 +1831,24 @@ cy = start;
 over_filter = 0;
 over_osc = 0;
 
+mnode = 1;
 //input_size = 
 <?
   loop(i=0;8,
     printf("n1%d.node(cx, cy, block_size, block_size, 0, 0);", i);
     printf("n1%d.over ? (over_osc = %d; (last_cap == 0 && mouse_cap == 1) ? osc%d_enabled = 1 - osc%d_enabled; );", i, i + 1, i + 1, i + 1);
-    
+ 
     printf("osc%d_enabled ? gfx_rect(cx, cy, block_size, block_size);", i + 1);
     printf("cy += block_size + 2;");
     i += 1;
   );
 ?>
 
+function has_feedback(v)
+(
+  (v > 5) && (v < 10);
+);
+
 cx = left_side + block_size + spacing;
 cy = start + 0.5 * (block_size + 2);
 // LAST
@@ -1826,8 +1856,15 @@ cy = start + 0.5 * (block_size + 2);
   current_slider = 128; /* First mix slider */
   loop(i=0;4,
     printf("n2%d.mix_node(cx, cy, 2 * block_size + 2, block_size, %d);", i, current_slider);
+    
+    printf("has_feedback(mix_mode%d) ? (", i + 1);
+      printf("f_fb_slider%d.active = 1;", mnode);
+      printf("f_fb_slider%d.color = 0.1;", mnode);
+      printf("f_fb_slider%d.text_slider_ui(%d, cx, cy + block_size + 1, 2 * block_size + 2, 5, \"\", \"Feedback\", sprintf(1, \"Feedbk (%%d)\", 100 * f_fb_slider%d.display_value));", mnode, uuid(), mnode);
+    printf(");", i);
+    
     printf("cy += 2 * (block_size + 2);");
-    i += 1;
+    i += 1; mnode += 1;
     current_slider += 1;
   );
 ?>
@@ -1838,8 +1875,15 @@ cy = start + 0.5 * 3 * (block_size + 2);
 <?
   loop(i=0;2,
     printf("n3%d.mix_node(cx, cy, 2 * block_size + 2, block_size, %d);", i, current_slider);
+    
+    printf("has_feedback(mix_mode2%d) ? (", i + 1);
+      printf("f_fb_slider%d.active = 1;", mnode);
+      printf("f_fb_slider%d.color = 0.1;", mnode);
+      printf("f_fb_slider%d.text_slider_ui(%d, cx, cy + block_size + 1, 2 * block_size + 2, 5, \"\", \"Feedback\", sprintf(1, \"Feedbk (%%d)\", 100 * f_fb_slider%d.display_value));", mnode, uuid(), mnode);
+    printf(");", i);
+    
     printf("cy += 4 * (block_size + 2);");
-    i += 1;
+    i += 1; mnode += 1;
     current_slider += 1;
   );
 ?>
@@ -1861,6 +1905,15 @@ cx = left_side + 7 * block_size + 4 * spacing;
 cy = start + 3.5 * (block_size + 2);
 n5.mix_node(cx, cy, 2 * block_size + 2, block_size, 134);
 
+<?
+i = 0;
+printf("has_feedback(mix_mode2%d) ? (", i + 1);
+  printf("f_fb_slider%d.active = 1;", mnode);
+  printf("f_fb_slider%d.color = 0.1;", mnode);
+  printf("f_fb_slider%d.text_slider_ui(%d, cx, cy + block_size + 1, 2 * block_size + 2, 5, \"\", \"Feedback\", sprintf(1, \"Feedbk (%%d)\", 100 * f_fb_slider%d.display_value));", mnode, uuid(), mnode);
+printf(");", i);
+?>
+
 cy += 4 * (block_size + 2);
 cx += 2 * block_size + spacing;
 cy = start + 3.5 * (block_size + 2);