Why wasn't Luke affected by Obi-Wan's voice?

I've often wondered about that. He's in his X-Wing, and he's about to go into a battle that could easily render him dead. That's enough to stir strong emotions on the spot. Then, Obi-Wan's voice comes out of nowhere, and Luke doesn't even have a reaction. He just goes about his business ignoring it, as if it never happened. I mean, if I was in Luke's spot I'd at least get startled, and then ask "Ben is that you?" I mean, who wouldn't?

 

Maybe 'cause he's heard his voice before? Obi-Wan did tell Luke to run away on the Death Star shortly after his death.

L8r

 

plus you could assume he's BEEN talking to him a lot since they left the deathstar, so nothing new

 

Luke's heard it before. Ben's voice probably even made Luke more relaxed.

 

I thought he tapped his helmet in reaction to it the first time in the X-Wing.

 

I always thought Luke was tapping his helmet and kind of writing Obi-Wan's voice off as some kind of distortion over the ship-to-ship radio. He didn't have time to really think about it, either, he had more immediate things, like the battle, occupying his attention. But he still didn't understand what was happening.

 

Doesn't Obi-Wan tell Luke to let go or something?, like saying you must have Faith. Luke trusted Obi-Wan's voice and didn't question what was going on, because he had faith in the Force.

 

I think the first time Luke hear's in it the X-Wing at first he does not really believe that it's Obi-Wan. He just thinks it's own thought or a radio malfunction(like that one guy said) or whatever.