diff --git a/sound/sources/sample_reader.hpp b/sound/sources/sample_reader.hpp
index 16b98bee3..1cf9f5f68 100644
--- a/sound/sources/sample_reader.hpp
+++ b/sound/sources/sample_reader.hpp
@@ -11,22 +11,28 @@ namespace Sound {
      insist on reading whole samples rather than bytes. This class
      compensates for that, and allows you to read bytes rather than
      samples.
+
+     There are two ways for subclasses to use this class. EITHER call
+     setup() with the size of frameSize. This will allocate a buffer,
+     which the destructor frees. OR set frameSize manually and
+     manipulate the pullOver pointer yourself. In that case you MUST
+     reset it to NULL if you don't want the destructor to call
+     delete[] on it.
    */
 class SampleReader : public SampleSource
 {
-  // Pullover buffer
-  char* pullOver;
-
   // How much of the above buffer is in use.
   int pullSize;
 
 protected:
+  // Pullover buffer
+  char* pullOver;
+
   // Size of one frame, in bytes. This is also the size of the
   // pullOver buffer.
   int frameSize;
 
-  // MUST be called by base class constructor. The parameter gives the
-  // size of one sample/frame, in bytes.
+  // The parameter gives the size of one sample/frame, in bytes.
   void setup(int);
 
   // Read the given number of samples, in multiples of frameSize. Does
@@ -34,7 +40,7 @@ protected:
   virtual size_t readSamples(void *data, size_t num) = 0;
 
  public:
-  SampleReader() : pullOver(NULL) {}
+  SampleReader() : pullOver(NULL), pullSize(0) {}
   ~SampleReader();
   size_t read(void *data, size_t length);
 };