you need one AVR micro controller like ATMega16
one IIC based RTC – real time clock
and two relays – to switch on or off any speaker system
program the RTC as per your requirement. it can give alarm signal similar to normal alarm watch. so you can set alarm as per your convenience like 4 hrs, 5 hrs, 6 hrs etc
to program and control RTC you need AVR micro controller. follow the AVR and RTC tutorials on
EG labs / micro controllers / AVR on this site