Spc in process control?
Answers:
I'm not sure what your sound out is, but here are some suitable links on statistical process control ...
http://reliability.sandia.gov/manuf_stat...
http://www.isixsigma.com/st/control_char...
http://lorien.ncl.ac.uk/ming/spc/spc0.ht...
What? Could you be a bit more clear?