DECENT RATES,SECOND OFFICER VOICE COMMANDS

Hi all new to forum I have two questions to ask1. decent rates; when using fs9 atc the decent rates are about 1800fpm, with the 737 I build up to much speed and on final I am either to fast or to high. The flight manule says not to use flaps to slow the aircraft on decent. can you change fs9 decent rates? or is it ok to use some flaps on decent.(I wonder how real pilots handle high decent rates)2.there two voices you here in the cockpit, one is the computer generated alltitude warnings,(like when you land) that one is loud and clear. But there is another voice(second officer i assume) who calls v speeds,flaps and such, I can barley hear it,is there any way to turn that volume up.