In the HEAD/trunk function plotorbits2dfloat, line 2009 declares x, y, and z as doubles. Lines 2029-2034 use the sound flags to determine which variable should be used for sound output and initialize the pointer soundvar to one of x, y, or z. None of x, y, or z has been initialized yet. On line 2071, x, y, or z is used through soundvar to output a tone based on the orbit computation and the flags. However, this will always output junk sounds because x, y, and z are never set to anything and are only used as addresses for soundvar. I'm not sure what this should be here, but it looks like bogus code and I'm removing the sound output on the branch. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>