yes, 50 samples of pitches for rounding.  It is a magic number I made up -- it's 50 buffers-worth, and I guess we could try to calculate a better number based on how many buffers it takes to get one revolution of the platter, since that's the period over which there's the most variation. 

That would be (1000 * 60) / (latency_ms * RPM) = buffers / revolution.   Hm I wonder if I can get latency from vinylcontrolxwax?