Depends on the system of course; with power hungry speakers you could go past noon. I've read tho that clipping starts before it's audible, and not near as loud a setting as you'd think.
clipping and max rated watts/max volume
Does clipping and max power/max volume usually occur before the volume knob is turned all the way to it's maximum full rotation? What point is typically full power unclipped / max volume? i.e. -Volume knob around half to 3/4 way to max rotation?