"Force Is Strong In This One..."

Ok, Ben's voice pops up in Luke's head telling him to use the Force to take out the Death Star. The only indication that Vader noticed this is the above quote. I'm wondering, do you think Vader was able to, or in fact, DID hear Ben's voice also? Or did he just feel another "tremor" in the Force? Maybe he did hear Obi-Wan and that was the seed of his figuring out that Luke was his son and trying to find him by ESB.
Oh well...random thoughts on a Monday; hope everyone's doing well out there!

 

He just felt a tremor. Vader learnt about Luke's true identity sometime between ANH and ESB.

 

He just felt a tremor.

 

I actually think that the tremor he felt could have been Ben, rather than Luke. Vader says this immediately after Ben calls to Luke, and Ben said he'd be "more powerful than [Vader] could possibly imagine."

 

Whether he head Ben's voice or not, I'm pretty sure he was reffering to Luke when he said: The Force is strong in this one...."

 

I didn't say Vader heard Ben, simply that it was Ben that Vader felt. Watch the scene again - Luke isn't doing anything with the Force when Ben "talks" to him, and Vader immediately says "Force Is Strong In This One...". It's after this scene that Luke uses the Force.

Also, keep in mind that Ben is one with the Force at this point. He comes to Luke as the Force, and this is what Vader senses. It's really not a stretch at all.