What speakers? You would be able to continue to use the speakers in the projector if it has them but you would not want to. You would want all your sources going to the AVR directly and speakers connected to that.
I m planning to buy Focal Sib and Cub 5.1 speakers along with AV receiver.
The Projector i have is Acer H6510BD, this has Audio input and output (3.5mm jack ) and 2 HDMI Inputs
but there is no composite Audio Video Output slots. So i Was wondering how would i connect 5.1 speakers and AV reciever. Is it only via HDMI ( coz no composite Audio Video output from my Projector)