sound on Blu-ray seems to be very quiet?

[Dan2k9]

hi, first of all im sorry if this has been covered already, but i have done a quick search and nothing came up,

what i was wondering is, in my experience the majority of Blu-rays that i have, seem to be really quiet? ie, i have to almost double the volume on my tv, Usually i have it around 22, but for Blu-ray it needs to be up close to 40 so i can actually hear it, or does this depend on my setup, i am using a sony bravia tv and a sony s350 Blu-ray player, but i do not have a surround system yet, maybe this is the problem? sorry if i seem a little naive.