Guitarpima
The pre/post is:
Pre - any effects in the PC (pro channel) and/or effects bin happen before the fader. The fader is the volume slider.
Post - any effects in the PC and/or the effects bin happen after the fader.
I believe, without checking, the effects bin happens after the PC. (clarify anyone?)
The picture poster by the OP shows the
send pre, which determines whether the send is before or after the fader.
The
ProChannel post button determines whether the ProChannel comes before the FX bin (default) or after it.
There is a blog on the Cake site about signal flow in Sonar that is well worth a look. If I get time I'll post a link.