how can i set read speed?

I can't seem to set the read speed for my burner. Im having trouble with images so i trying to set my burner to read at a slower speed but when i use dvd decrypter i tell it to read slower but still does not. I've even tryed alcahol but it does not let me ajust the read speed. its like my drive is locked when it comes to read speed. Can someone help me out?