ventilation question for my next set up

ok heres the deal.i wanna start a new grow next month with a 600w hps + cfl's in a fortunately white room like 3width*3length*3height.of course 600w is fine for just 1,20*1,20.my question is am i gonna need ventilation for the whole room or just some 300somethingcubicm/hour for the space i am growing under the lamp?thanks.(i cant do that with feet and inches just metres)

you have to make a cool tube and you have to have ventilation. if not your room is going to get super super super hot with a 3x3x3 room in the summer time

I have a pic of my setup here. It is a very small room with a cool tube + 400W HPS. without the cooltube and ducting the room is waaaay too hot.

hm youre right guys.so if i have a cool tube then i only need intake fan?

I have a fan sucking hot air away from the cooltube and out of the room, a couple of computer fans bring air into the room + a desk fan inside the room to distribute air. My temps stayed between 24C - 26C

yes exactly.the fan suckin air is just a simple fan?