darkesprit

ok so... when i'm watching a dvd on my pc (original or not) when i can't use my speakers (cos ppl are sleeping lol) I try to plug in my headphones instead but, when i do i hear every sound (music etc), but i don't hear the actors voices!!! 0_o i mean not even a whisper, NOTHINg their voices are just 'cut off' when i'm using headphones..!
please help me out cos soemtimes it's really impossible to hear a thing they say in the movies when u have speakers at low volume :S and i need to use my headphones..!