diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index a22370da8..86eebfa31 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -3282,6 +3282,10 @@ void DivEngine::quitDispatch() {
   for (int i=0; i<DIV_MAX_CHANS; i++) {
     isMuted[i]=0;
   }
+  if (renderPool!=NULL) {
+    delete renderPool;
+    renderPool=NULL;
+  }
   BUSY_END;
 }
 
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 7582c9efb..6f6414225 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1797,7 +1797,10 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
   std::chrono::steady_clock::time_point ts_processBegin=std::chrono::steady_clock::now();
 
   if (renderPool==NULL) {
-    renderPool=new DivWorkPool(renderPoolThreads);
+    unsigned int howManyThreads=song.systemLen;
+    if (howManyThreads<2) howManyThreads=0;
+    if (howManyThreads>renderPoolThreads) howManyThreads=renderPoolThreads;
+    renderPool=new DivWorkPool(howManyThreads);
   }
 
   // process MIDI events (TODO: everything)