diff --git a/Source/synth/lfo.c b/Source/synth/lfo.c
index ec456aa..c99ddbd 100644
--- a/Source/synth/lfo.c
+++ b/Source/synth/lfo.c
@@ -14,10 +14,7 @@
 // --------------------------------------------------------------
 void LFO_set_omega(lfo_t *pObj, synth_float_t omega)
 {
-	if (omega < 0.0 || omega > 1.0)
-	{
-		return;
-	}
+	omega = fmin(0.5, fmax(-0.5, omega));
 	pObj->b = 2.0 * sin(omega*pi);
 	pObj->dx = omega;
 }
@@ -77,8 +74,21 @@ synth_float_t Sync_mod(synth_float_t x, synth_float_t y)
 	return result;
 }
 
+synth_float_t phase_det(synth_float_t lo, synth_float_t ref)
+{
+	lo = Sync_mod(lo - 0.5, 1.0);
+	synth_float_t perr = Sync_mod(lo - ref, 1.0) - (synth_float_t)0.5;
+	
+	return perr;
+}
+
 void Sync_init(sync_t *pObj)
 {
+	pObj->pFuncObj = NULL;
+	pObj->funcSyncOnProcess = NULL;
+	pObj->funcSyncOnGetPhase = NULL;
+	pObj->funcSyncOnFreqUpdate = NULL;
+	
 	pObj->phase = 0;
 	pObj->phase_ref = 0;
 	pObj->omega = 0.0;
@@ -88,6 +98,14 @@ void Sync_init(sync_t *pObj)
 	pObj->phase_update = 0;
 }
 
+void Sync_set_callback(sync_t *pObj, void *pFuncObj, SyncOnProcess funcSyncOnProcess, SyncOnGetPhase funcSyncOnGetPhase, SyncOnFreqUpdate funcSyncOnFreqUpdate)
+{
+	pObj->pFuncObj = pFuncObj;
+	pObj->funcSyncOnProcess = funcSyncOnProcess;
+	pObj->funcSyncOnGetPhase = funcSyncOnGetPhase;
+	pObj->funcSyncOnFreqUpdate = funcSyncOnFreqUpdate;
+}
+
 void Sync_phase_update(sync_t *pObj, synth_float_t phase_ref)
 {
 	pObj->phase_ref = phase_ref;
@@ -98,21 +116,52 @@ int Sync_process(sync_t *pObj)
 {
 	int do_lfo_update = 0;
 	synth_float_t perr = 0;
+	if (pObj->funcSyncOnProcess)
+	{
+		(*pObj->funcSyncOnProcess)(pObj->pFuncObj);
+	}
 	if (pObj->phase_update)
 	{
-		do_lfo_update = 1;
 		pObj->phase_update = 0;
-		synth_float_t phase_lo = Sync_mod(pObj->phase - 0.5, 1.0);
-		perr = (synth_float_t)Sync_mod(phase_lo - pObj->phase_ref, 1.0) - (synth_float_t)0.5;
-		SynthDebug("phase_ref=%f, phase_lo=%f, perr=%f\n", pObj->phase_ref, pObj->phase, perr);
+		do_lfo_update = 1;
+		if (pObj->funcSyncOnGetPhase)
+		{
+			synth_float_t phase = (*pObj->funcSyncOnGetPhase)(pObj->pFuncObj);
+			perr = phase_det(phase, pObj->phase_ref);
+			SynthDebug("phase_ref=%f, phase_lo=%f, perr=%f\n", pObj->phase_ref, pObj->phase, perr);
+		}
+		if (pObj->funcSyncOnFreqUpdate)
+		{
+			(*pObj->funcSyncOnFreqUpdate)(pObj->pFuncObj, pObj->omega);
+		}
 	}
-	pObj->phase = Sync_mod(pObj->phase + pObj->omega, 1.0);
-	pObj->omega = -(pObj->klag*pObj->accu + pObj->klead*perr);
 	pObj->accu += perr;
-	
+	pObj->omega = -(pObj->klag*pObj->accu + pObj->klead*perr);
+
 	return do_lfo_update;
 }
 
+void syncOnProcess(void *pFuncObj)
+{
+	lfo_t *pObj = (lfo_t*)pFuncObj;
+	pObj->sync.phase = Sync_mod(pObj->sync.phase + pObj->sync.omega, 1.0);
+}
+
+synth_float_t syncOnGetPhase(void *pFuncObj)
+{
+	lfo_t *pObj = (lfo_t*)pFuncObj;
+	SynthDebug("syncOnGetPhase()\n");
+	
+	return pObj->sync.phase;
+}
+
+void syncOnFreqUpdate(void *pFuncObj, synth_float_t omega)
+{
+	lfo_t *pObj = (lfo_t*)pFuncObj;
+	SynthDebug("syncOnFreqUpdate(): BPM=%f\n", omega*pObj->fs*60);
+}
+
+
 // --------------------------------------------------------------
 // Exported functions
 // --------------------------------------------------------------
@@ -143,6 +192,7 @@ void LFO_Init(lfo_t *pObj, synth_float_t fs)
 	Noise_Init(&pObj->noise, 1+(UINT32)clock() * (UINT32)clock());
 	
 	Sync_init(&pObj->sync);
+	Sync_set_callback(&pObj->sync, pObj, syncOnProcess, syncOnGetPhase, syncOnFreqUpdate);
 }
 
 void LFO_Free(lfo_t *pObj)
@@ -276,10 +326,9 @@ synth_float_t* LFO_ProcessDataV(lfo_t *pObj, UINT32 len)
 			if (Sync_process(&pObj->sync))
 			{
 				LFO_set_omega(pObj, pObj->sync.omega);		
-				SynthDebug("BPM=%f\n", pObj->sync.omega*pObj->fs*60);
 			}
 			pObj->x = pObj->sync.phase;
-
+			
 			in = pObj->x + pObj->offset;
 			pObj->out = pObj->smooth_a*pObj->out + pObj->smooth_b*in;
 			out = pObj->out;
@@ -289,11 +338,7 @@ synth_float_t* LFO_ProcessDataV(lfo_t *pObj, UINT32 len)
 			*(pOut++) = out*pObj->attack_y;
 			pObj->attack_y += pObj->attack_a*(1-pObj->attack_y);
 
-			pObj->x += pObj->dx;
-			if (pObj->x >= 1.f)
-			{
-				pObj->x -= 1.f;
-			}
+			pObj->x = Sync_mod(pObj->x + pObj->dx, 1.0);
 
 			if (pObj->freq_update_req)
 			{
@@ -317,11 +362,7 @@ synth_float_t* LFO_ProcessDataV(lfo_t *pObj, UINT32 len)
 			*(pOut++) = out*pObj->attack_y;
 			pObj->attack_y += pObj->attack_a*(1-pObj->attack_y);
 
-			pObj->x += pObj->dx;
-			if (pObj->x >= 1.f)
-			{
-				pObj->x -= 1.f;
-			}
+			pObj->x = Sync_mod(pObj->x + pObj->dx, 1.0);
 
 			if (pObj->freq_update_req)
 			{
@@ -567,11 +608,7 @@ synth_float_t* LFO_ProcessDataV(lfo_t *pObj, UINT32 len)
 			else
 				pObj->tri = 2*(1-pObj->x);
 
-			pObj->x += pObj->dx;
-			if (pObj->x >= 1.f)
-			{
-				pObj->x -= 1.f;
-			}
+			pObj->x = Sync_mod(pObj->x + pObj->dx, 1.0);
 
 			if (pObj->freq_update_req)
 			{
@@ -600,11 +637,7 @@ synth_float_t* LFO_ProcessDataV(lfo_t *pObj, UINT32 len)
 			else
 				pObj->tri = 2*(1-pObj->x);
 
-			pObj->x += pObj->dx;
-			if (pObj->x >= 1.f)
-			{
-				pObj->x -= 1.f;
-			}
+			pObj->x = Sync_mod(pObj->x + pObj->dx, 1.0);
 
 			if (pObj->freq_update_req)
 			{
diff --git a/Source/synth/lfo.h b/Source/synth/lfo.h
index 9f2f6da..32ab42c 100644
--- a/Source/synth/lfo.h
+++ b/Source/synth/lfo.h
@@ -40,8 +40,16 @@ enum
 	LFO_NUM_PARAMS
 };
 
+typedef void (*SyncOnProcess)(void *pFuncObj); 
+typedef void (*SyncOnFreqUpdate)(void *pFuncObj, synth_float_t omega);
+typedef synth_float_t (*SyncOnGetPhase)(void *pFuncObj);
 typedef struct _ssync_t
 {	
+	void *pFuncObj;
+	SyncOnProcess funcSyncOnProcess;
+	SyncOnGetPhase funcSyncOnGetPhase;
+	SyncOnFreqUpdate funcSyncOnFreqUpdate;
+	
 	synth_float_t phase;
 	synth_float_t phase_ref;
 	synth_float_t omega;
@@ -62,6 +70,8 @@ extern "C" {
 // Exported functions
 // --------------------------------------------------------------
 void Sync_init(sync_t *pObj);
+void Sync_set_callback(sync_t *pObj, void *pFuncObj, SyncOnProcess funcSyncOnProcess, SyncOnGetPhase funcSyncOnGetPhase, SyncOnFreqUpdate funcSyncOnFreqUpdate);
+
 void Sync_phase_update(sync_t *pObj, synth_float_t phase_ref);
 int Sync_process(sync_t *pObj);