diff --git a/cwFlow.cpp b/cwFlow.cpp
index b2a8fa5..ace5954 100644
--- a/cwFlow.cpp
+++ b/cwFlow.cpp
@@ -27,11 +27,15 @@ namespace cw
       { "audio_out",    &audio_out::members },
       { "audioFileIn",  &audioFileIn::members },
       { "audioFileOut", &audioFileOut::members },
+      { "gain",         &gain::members },
+      { "audio_split",  &audio_split::members },
+      { "audio_merge",  &audio_merge::members },
       { "sine_tone",    &sine_tone::members },
       { "pv_analysis",  &pv_analysis::members },
       { "pv_synthesis", &pv_synthesis::members },
       { "spec_dist",    &spec_dist::members },
       { "compressor",   &compressor::members },
+      { "audio_delay",  &audio_delay::members },
       { nullptr, nullptr }
     };
 
@@ -759,6 +763,40 @@ namespace cw
       
       return rc;
     }
+
+    template< typename T >
+    rc_t _set_variable_value( flow_t* p, const char* inst_label, const char* var_label, unsigned chIdx, T value )
+    {
+      rc_t        rc   = kOkRC;
+      instance_t* inst = nullptr;
+      variable_t* var  = nullptr;
+
+      // locate the proc instance
+      if((inst = instance_find(p,inst_label)) != nullptr )
+      {
+        rc = cwLogError(kInvalidIdRC,"Unknown proc instance label '%s'.", cwStringNullGuard(inst_label));
+        goto errLabel;
+      }
+
+      // locate the variable
+      if((rc = var_find( inst, var_label, chIdx, var)) != kOkRC )
+      {
+        rc = cwLogError(kInvalidArgRC,"The variable '%s' could not be found on the proc instance '%s'.",cwStringNullGuard(var_label),cwStringNullGuard(inst_label));
+        goto errLabel;
+      }
+
+      // set the variable value
+      if((rc = var_set( inst, var->vid, chIdx, value )) != kOkRC )
+      {
+        rc = cwLogError(kOpFailRC,"The variable set failed on instance:'%s' variable:'%s'.",cwStringNullGuard(inst_label),cwStringNullGuard(var_label));
+        goto errLabel;
+      }
+
+    errLabel:
+      return rc;
+    }
+
+    
     
   }
 }
@@ -870,6 +908,35 @@ cw::rc_t cw::flow::destroy( handle_t& hRef )
   return rc;
 }
 
+
+cw::rc_t cw::flow::exec_cycle( handle_t h )
+{
+  return _exec_cycle(_handleToPtr(h));
+}
+
+cw::rc_t cw::flow::exec(    handle_t h )
+{
+  rc_t    rc = kOkRC;
+  flow_t* p  = _handleToPtr(h);
+
+  while( true )
+  {  
+    rc = _exec_cycle(p);
+    
+    if( rc == kEofRC )
+    {
+      rc = kOkRC;
+      break;
+    }
+    
+    p->cycleIndex += 1;
+    if( p->maxCycleCount > 0 && p->cycleIndex >= p->maxCycleCount )
+      break;
+  }
+  
+  return rc;
+}
+
 cw::rc_t cw::flow::apply_preset( handle_t h, const char* presetLabel )
 {
   rc_t    rc = kOkRC;
@@ -911,6 +978,7 @@ cw::rc_t cw::flow::apply_preset( handle_t h, const char* presetLabel )
         if( preset_value_cfg->is_dict() )
         {
           printf("Not implemented.\n");
+          assert(0);
         }
         else
         {
@@ -930,33 +998,21 @@ cw::rc_t cw::flow::apply_preset( handle_t h, const char* presetLabel )
   return rc;
 }
 
-cw::rc_t cw::flow::exec_cycle( handle_t h )
-{
-  return _exec_cycle(_handleToPtr(h));
-}
+cw::rc_t cw::flow::set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, bool value )
+{ return _set_variable_value( _handleToPtr(h), inst_label, var_label, chIdx, value ); }
 
-cw::rc_t cw::flow::exec(    handle_t h )
-{
-  rc_t    rc = kOkRC;
-  flow_t* p  = _handleToPtr(h);
+cw::rc_t cw::flow::set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, int value )
+{ return _set_variable_value( _handleToPtr(h), inst_label, var_label, chIdx, value ); }
+
+cw::rc_t cw::flow::set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, unsigned value )
+{ return _set_variable_value( _handleToPtr(h), inst_label, var_label, chIdx, value ); }
+
+cw::rc_t cw::flow::set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, float value )
+{ return _set_variable_value( _handleToPtr(h), inst_label, var_label, chIdx, value ); }
+
+cw::rc_t cw::flow::set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, double value )
+{ return _set_variable_value( _handleToPtr(h), inst_label, var_label, chIdx, value ); }
 
-  while( true )
-  {  
-    rc = _exec_cycle(p);
-    
-    if( rc == kEofRC )
-    {
-      rc = kOkRC;
-      break;
-    }
-    
-    p->cycleIndex += 1;
-    if( p->maxCycleCount > 0 && p->cycleIndex >= p->maxCycleCount )
-      break;
-  }
-  
-  return rc;
-}
 
 void cw::flow::print_class_list( handle_t h )
 {
diff --git a/cwFlow.h b/cwFlow.h
index e6d31bc..13f23bf 100644
--- a/cwFlow.h
+++ b/cwFlow.h
@@ -59,15 +59,20 @@ namespace cw
     rc_t destroy( handle_t& hRef );
 
 
-    rc_t apply_preset( handle_t h, const char* presetLabel );
-    
     // Run one cycle of the network.
     rc_t exec_cycle( handle_t h );
 
     // Run the network to completion.
     rc_t exec(    handle_t h );
 
-    
+    rc_t apply_preset( handle_t h, const char* presetLabel );
+        
+    rc_t set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, bool value     );
+    rc_t set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, int value      );
+    rc_t set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, unsigned value );
+    rc_t set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, float value    );
+    rc_t set_variable_value( handle_t h, const char* inst_label, const char* var_label, unsigned chIdx, double value   );
+
     void print_class_list( handle_t h );
     void print_network( handle_t h );
 
diff --git a/cwFlowCross.cpp b/cwFlowCross.cpp
index a531471..ca17263 100644
--- a/cwFlowCross.cpp
+++ b/cwFlowCross.cpp
@@ -123,11 +123,13 @@ namespace cw
       dsp::recorder::create( net->recorder, srate, 10.0, 1 );
       
       net->deviceA = _clone_external_device_array( deviceA, deviceN );
-      net->deviceN = deviceN;
+      net->deviceN = 0;
       net->stateId = net_idx == 0 ? kActiveStateId : kInactiveStateId;
       net->net_idx = net_idx;
       
-      if((rc = flow::create( net->flowH, classCfg, networkCfg, net->deviceA, net->deviceN )) != kOkRC )
+      if((rc = flow::create( net->flowH, classCfg, networkCfg, net->deviceA, deviceN )) == kOkRC )
+        net->deviceN += 1;
+      else
       {
         cwLogError(rc,"Flow cross index %i network created failed.",net_idx);
         goto errLabel;
@@ -226,6 +228,33 @@ namespace cw
 
       _fade_audio( src, dst, net );
     }
+
+    unsigned _get_flow_index( flow_cross_t* p, destId_t destId )
+    {
+      unsigned flow_idx = kInvalidIdx;
+  
+      switch( destId )
+      {
+      case kCurDestId:  flow_idx = p->cur_idx; break;
+      case kNextDestId: flow_idx = (p->cur_idx + 1) % p->netN;
+      default:
+        assert(0);
+    
+      }  
+      return flow_idx;
+    }
+
+    template< typename T >
+    rc_t _set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, const T& value )
+    {
+      //rc_t          rc       = kOkRC;
+      flow_cross_t* p        = _handleToPtr(h);
+      unsigned      flow_idx = _get_flow_index(p, destId );
+      return set_variable_value( p->netA[ flow_idx ].flowH, inst_label, var_label, chIdx, value );
+  
+    }
+
+    
   }
 }
 
@@ -250,13 +279,15 @@ cw::rc_t cw::flow_cross::create( handle_t&                hRef,
 
   flow_cross_t* p = mem::allocZ<flow_cross_t>();
   p->netA         = mem::allocZ<flow_network_t>( crossN );
-  p->netN         = crossN;
+  p->netN         = 0;
   p->srate        = srate;
   p->deviceA = deviceA;
   p->deviceN = deviceN;
 
   for(unsigned i=0; i<crossN; ++i)
-    if((rc = _create_network(p,i,srate,classCfg,networkCfg,deviceA,deviceN)) != kOkRC )
+    if((rc = _create_network(p,i,srate,classCfg,networkCfg,deviceA,deviceN)) == kOkRC )
+      p->netN += 1;
+    else
     {
       rc = cwLogError(rc,"Sub-network index '%i' create failed.",i);
       goto errLabel;
@@ -339,35 +370,52 @@ cw::rc_t cw::flow_cross::exec_cycle( handle_t h )
 }
 */
 
-cw::rc_t cw::flow_cross::apply_preset( handle_t h, unsigned crossFadeMs, const char* presetLabel )
+
+
+cw::rc_t cw::flow_cross::apply_preset( handle_t h, destId_t destId, const char* presetLabel )
+{
+  rc_t          rc       = kOkRC;
+  flow_cross_t* p        = _handleToPtr(h);
+  unsigned      flow_idx = _get_flow_index(p, destId );
+      
+  if((rc = flow::apply_preset( p->netA[flow_idx].flowH, presetLabel )) != kOkRC )
+    rc = cwLogError(rc,"Preset application '%s' failed.",cwStringNullGuard(presetLabel));
+
+  return rc;  
+}
+
+cw::rc_t cw::flow_cross::set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, bool value )
+{  return _set_variable_value(h,destId,inst_label,var_label,chIdx,value); }
+
+cw::rc_t cw::flow_cross::set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, int value )
+{  return _set_variable_value(h,destId,inst_label,var_label,chIdx,value); }
+
+cw::rc_t cw::flow_cross::set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, unsigned value )
+{  return _set_variable_value(h,destId,inst_label,var_label,chIdx,value); }
+
+cw::rc_t cw::flow_cross::set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, float value )
+{  return _set_variable_value(h,destId,inst_label,var_label,chIdx,value); }
+
+cw::rc_t cw::flow_cross::set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, double value )
+{  return _set_variable_value(h,destId,inst_label,var_label,chIdx,value); }
+
+cw::rc_t cw::flow_cross::begin_cross_fade( handle_t h, unsigned crossFadeMs )
 {
   rc_t          rc = kOkRC;
   flow_cross_t* p = _handleToPtr(h);
-
-  unsigned next_idx = (p->cur_idx + 1) % p->netN;
-
-  // TODO: verify that this network is inactive
-
-  if((rc = flow::apply_preset( p->netA[next_idx].flowH, presetLabel )) != kOkRC )
-  {
-    cwLogError(rc,"Preset application '%s' failed.",cwStringNullGuard(presetLabel));
-    goto errLabel;
-  }
-
+  
   p->netA[ p->cur_idx ].stateId = kFadeOutStateId;
   
-  p->cur_idx                    = next_idx;
+  p->cur_idx                    = _get_flow_index( p, kNextDestId );
+  
   p->netA[ p->cur_idx ].stateId = kFadeInStateId;
   p->netA[ p->cur_idx ].fadeSmpN = (unsigned)(p->srate * crossFadeMs / 1000.0);
 
-  cwLogInfo("Apply preset:%s.",presetLabel);
-  
- errLabel:
-  
   return rc;
 }
 
 
+
 void cw::flow_cross::print( handle_t h )
 {
   flow_cross_t* p = _handleToPtr(h);
diff --git a/cwFlowCross.h b/cwFlowCross.h
index 17b703d..5b5e949 100644
--- a/cwFlowCross.h
+++ b/cwFlowCross.h
@@ -8,6 +8,12 @@ namespace cw
 
     typedef handle<struct flow_cross_str> handle_t;
 
+    typedef enum
+    {
+      kCurDestId,   // Apply value to the current flow network 
+      kNextDestId,  // Apply value to the next flow network (i.e. network which will be current following the next cross-fade)
+    } destId_t;
+
     rc_t create( handle_t&                hRef,                 
                  const object_t&          classCfg,
                  const object_t&          networkCfg,
@@ -21,8 +27,16 @@ namespace cw
     // Run one cycle of the network.
     rc_t exec_cycle( handle_t h );
     
-    rc_t apply_preset( handle_t h, unsigned crossFadeMs, const char* presetLabel );
+    rc_t apply_preset( handle_t h, destId_t destId, const char* presetLabel );
 
+    rc_t set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, bool value );
+    rc_t set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, int value );
+    rc_t set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, unsigned value );
+    rc_t set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, float value );
+    rc_t set_variable_value( handle_t h, destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, double value );
+
+    rc_t begin_cross_fade( handle_t h, unsigned crossFadeMs );
+    
     void print( handle_t h );
     
   }
diff --git a/cwIoFlow.cpp b/cwIoFlow.cpp
index d1790e9..895f126 100644
--- a/cwIoFlow.cpp
+++ b/cwIoFlow.cpp
@@ -406,13 +406,23 @@ cw::rc_t cw::io_flow::exec( handle_t h, const io::msg_t& msg )
 }
 
 
-cw::rc_t cw::io_flow::apply_preset( handle_t h, double crossFadeMs, const char* presetLabel )
-{
-  cw::rc_t rc = kOkRC;
+cw::rc_t cw::io_flow::apply_preset( handle_t h, flow_cross::destId_t destId, const char* presetLabel )
+{ return apply_preset( _handleToPtr(h)->crossFlowH, destId, presetLabel ); }
 
-  io_flow_t* p = _handleToPtr(h);
+cw::rc_t cw::io_flow::set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, bool value )
+{ return flow_cross::set_variable_value( _handleToPtr(h)->crossFlowH, destId, inst_label, var_label, chIdx, value ); }
 
-  rc = apply_preset( p->crossFlowH, crossFadeMs, presetLabel );
-  
-  return rc;
-}
+cw::rc_t cw::io_flow::set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, int value )
+{ return flow_cross::set_variable_value( _handleToPtr(h)->crossFlowH, destId, inst_label, var_label, chIdx, value ); }
+
+cw::rc_t cw::io_flow::set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, unsigned value )
+{ return flow_cross::set_variable_value( _handleToPtr(h)->crossFlowH, destId, inst_label, var_label, chIdx, value ); }
+
+cw::rc_t cw::io_flow::set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, float value )
+{ return flow_cross::set_variable_value( _handleToPtr(h)->crossFlowH, destId, inst_label, var_label, chIdx, value ); }
+
+cw::rc_t cw::io_flow::set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, double value )
+{ return flow_cross::set_variable_value( _handleToPtr(h)->crossFlowH, destId, inst_label, var_label, chIdx, value ); }
+
+cw::rc_t cw::io_flow::begin_cross_fade( handle_t h, unsigned crossFadeMs )
+{ return flow_cross::begin_cross_fade( _handleToPtr(h)->crossFlowH, crossFadeMs ); }
diff --git a/cwIoFlow.h b/cwIoFlow.h
index 54720d7..fe4da0d 100644
--- a/cwIoFlow.h
+++ b/cwIoFlow.h
@@ -12,7 +12,16 @@ namespace cw
 
     rc_t exec( handle_t h, const io::msg_t& msg );
 
-    rc_t apply_preset( handle_t h, double crossFadeMs, const char* presetLabel );
+
+    rc_t apply_preset( handle_t h, flow_cross::destId_t destId, const char* presetLabel );
+
+    rc_t set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, bool value );
+    rc_t set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, int value );
+    rc_t set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, unsigned value );
+    rc_t set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, float value );
+    rc_t set_variable_value( handle_t h, flow_cross::destId_t destId, const char* inst_label, const char* var_label, unsigned chIdx, double value );
+
+    rc_t begin_cross_fade( handle_t h, unsigned crossFadeMs );
     
 
   }