diff --git a/src/engine/dispatchContainer.cpp b/src/engine/dispatchContainer.cpp
index 22c63d67..46320691 100644
--- a/src/engine/dispatchContainer.cpp
+++ b/src/engine/dispatchContainer.cpp
@@ -83,6 +83,7 @@ void DivDispatchContainer::setRates(double gotRate) {
   int outs=dispatch->getOutputCount();
 
   for (int i=0; i<outs; i++) {
+    if (bb[i]==NULL) continue;
     blip_set_rates(bb[i],dispatch->rate,gotRate);
   }
   rateMemory=gotRate;
@@ -92,6 +93,16 @@ void DivDispatchContainer::setQuality(bool lowQual) {
   lowQuality=lowQual;
 }
 
+void DivDispatchContainer::grow(size_t size) {
+  bbInLen=size;
+  for (int i=0; i<DIV_MAX_OUTPUTS; i++) {
+    if (bbIn[i]!=NULL) {
+      delete[] bbIn[i];
+      bbIn[i]=new short[bbInLen];
+    }
+  }
+}
+
 void DivDispatchContainer::acquire(size_t offset, size_t count) {
   int outs=dispatch->getOutputCount();
   for (int i=0; i<DIV_MAX_OUTPUTS; i++) {
@@ -108,20 +119,44 @@ void DivDispatchContainer::flush(size_t count) {
   int outs=dispatch->getOutputCount();
 
   for (int i=0; i<outs; i++) {
+    if (bb[i]==NULL) continue;
     blip_read_samples(bb[i],bbOut[i],count,0);
   }
 }
 
 void DivDispatchContainer::fillBuf(size_t runtotal, size_t offset, size_t size) {
   int outs=dispatch->getOutputCount();
+
+  // create missing buffers if any
+  bool mustClear=false;
+  for (int i=0; i<outs; i++) {
+    if (bb[i]==NULL) {
+      bb[i]=blip_new(bbInLen);
+      if (bb[i]==NULL) {
+        logE("not enough memory!");
+        return;
+      }
+      blip_set_rates(bb[i],dispatch->rate,rateMemory);
+
+      if (bbIn[i]==NULL) bbIn[i]=new short[bbInLen];
+      if (bbOut[i]==NULL) bbOut[i]=new short[bbInLen];
+      memset(bbIn[i],0,bbInLen*sizeof(short));
+      memset(bbOut[i],0,bbInLen*sizeof(short));
+    }
+  }
+  if (mustClear) clear();
+
   if (dcOffCompensation && runtotal>0) {
     dcOffCompensation=false;
     for (int i=0; i<outs; i++) {
+      if (bbIn[i]==NULL) continue;
       prevSample[i]=bbIn[i][0];
     }
   }
   if (lowQuality) {
     for (int i=0; i<outs; i++) {
+      if (bbIn[i]==NULL) continue;
+      if (bb[i]==NULL) continue;
       for (size_t j=0; j<runtotal; j++) {
         temp[i]=bbIn[i][j];
         blip_add_delta_fast(bb[i],j,temp[i]-prevSample[i]);
@@ -130,6 +165,8 @@ void DivDispatchContainer::fillBuf(size_t runtotal, size_t offset, size_t size)
     }
   } else {
     for (int i=0; i<outs; i++) {
+      if (bbIn[i]==NULL) continue;
+      if (bb[i]==NULL) continue;
       for (size_t j=0; j<runtotal; j++) {
         temp[i]=bbIn[i][j];
         blip_add_delta(bb[i],j,temp[i]-prevSample[i]);
@@ -139,6 +176,8 @@ void DivDispatchContainer::fillBuf(size_t runtotal, size_t offset, size_t size)
   }
 
   for (int i=0; i<outs; i++) {
+    if (bbOut[i]==NULL) continue;
+    if (bb[i]==NULL) continue;
     blip_end_frame(bb[i],runtotal);
     blip_read_samples(bb[i],bbOut[i]+offset,size,0);
   }
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 219c468b..2eaf4127 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -181,6 +181,7 @@ struct DivDispatchContainer {
 
   void setRates(double gotRate);
   void setQuality(bool lowQual);
+  void grow(size_t size);
   void acquire(size_t offset, size_t count);
   void flush(size_t count);
   void fillBuf(size_t runtotal, size_t offset, size_t size);
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index c1a52bee..aae80297 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1601,12 +1601,8 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
       disCont[i].runtotal=blip_clocks_needed(disCont[i].bb[0],size-disCont[i].lastAvail);
     }
     if (disCont[i].runtotal>disCont[i].bbInLen) {
-      logV("growing dispatch %d bbIn to %d",i,disCont[i].runtotal+256);
-      delete[] disCont[i].bbIn[0];
-      delete[] disCont[i].bbIn[1];
-      disCont[i].bbIn[0]=new short[disCont[i].runtotal+256];
-      disCont[i].bbIn[1]=new short[disCont[i].runtotal+256];
-      disCont[i].bbInLen=disCont[i].runtotal+256;
+      logD("growing dispatch %d bbIn to %d",i,disCont[i].runtotal+256);
+      disCont[i].grow(disCont[i].runtotal+256);
     }
     disCont[i].runLeft=disCont[i].runtotal;
     disCont[i].runPos=0;