Would you consider this normal for his age? - Page 2

Just lack of socialization. You might try taking him out late in the evening when its light, and then staying out until its dark in the areas where he was frightened.

For me.............. I would think mostly normal. IF, and if it was his first time experiencing that experience he is going to step back and put it all together...........he just experienced it for the first time. Without seeing the action(s) I would not even think of him being afraid.
For the RAP music, one if it was loud, then you have the loudness he is trying to put a finger (paw) on. But if the bass is kicken then you have the vibration. Ever sit at a red light/stop sign and the vehicle next to you or behind you is thumping??? And you're getting a massage? That, I would think plus the loudness is what happened. Another thing.....................Remeber what a pup is seeing at their eye level not yours and maybe it was darker than he's used to be out?? But as a pup they're taking everything in in curiousity and he could have been on one side of your body/legs looking smelling something and then walked around/behind you and BAM right in front of him are two large objects......and he has to take a step back to take it all in. I would not worry one bit. When my latest pup and I would be out at night, (on a farm) and all the noises of the wild were around/about and if she heard an animal she wasn't sure of she would backtrack to Master and stay near him. Not a problem in my eyes whatsoever!  
 

I would be concerned.

This is an interesting topic. I got a male GSD when he was 6 months old. He is now 18 months. An intelligent awesome pup. He loves people. However, there are a few people (Men) that he backs away from and will NOT go near to this day. Sometimes I think he is just a great judge of character, but I wonder why he does this. I didn't see his first 6 months of life and don't know what he experienced. Any thoughts?

Denis, while you're at work, does he get crated when they come over?

No, he is not crated. It could be someone completely new as well. Especially men. But the next guy he meets he is all over them.

There are 2 people in particular, he will not let them touch him. He is not aggressive with them, he just doesn't want them near him. One of the men desperately wants to be his friend, but it just will not happen.

Denis, you need to allow your dog to go up to them, have them ignore your dog and pretend he doesn't even exist. Let your dog get use to them on his terms.  A dog I worked with in KY one time, the owner told me no one other than her had ever pet her dog before.....ever...... Within 5 minutes I was petting her dog. I got down on the dogs level, let it approach me, get comfortable, then I closed a treat in my hand.....it got closer and more comfortable..... I gave the treat, a couple of treats later, I was scratching under the chin as it tried to get the treat out of my hand. And a couple of minutes later I was petting it on the head without using treats.  

That's some dog whisperer shiznit there.

I should clarify. I have helped him like many others that he has backed away from and he will now run out the door to see them. He just will not open up to these two