Am making this thread for the singer in my band.

He's got a great voice, unexperienced when it comes to bands and somewhat 'professional' singing, but has really good tone and pitching.

One thing that we've noticed is that his voice seems to 'fit' better with acoustic, laid back sounds rather than more upfront, rock sounding vocals. I've been thinking about it and have realised it's probably because most of his singing experience has been with acoustic music and has never really pushed his voice to create a different timbre.

I was going to ask, how do you go about projecting your voice and getting a more aggressive tone?
This is some high level stuff your asking about. He needs good diaphragm support, relaxes throat, good grip onproper breathing and a knknowledge of his hard and soft pallets.

With that said there are more than one way to get the sound your looking for. The safest is to not add any crunch but instead increase presence. Have him attempt to guide his air towards the bony roof of his mouth. This will help resonate and give a more powerful sound. Secondly have him yawn and hold the position that theyawn causes in the back of his mouth. This is raising the soft pallet. The soft pallet absorbs a lot of the sound your wanting to project out. Try that out and see if it helps. Once he has that down have him come back with a recorded clip.
It depends on what you mean by rock vocals really. What do you mean by projecting the voice? Does he sing in a very low volume? Does his tone sound weird, muffled or choked? Do you have any specific singer, for example, in mind whose songs he wants to sing?
This is a very standard type of vocals, not just limited to rock. So what he needs to do is get some general vocal lessons. Don't expect that he can sing like that with low volume, he will have to push his voice at least at 60% (1% being the softest whisper and 100% the loudest yelling). The psychological factor plays a huge role in singing...he must get rid of any fear of exposure and become able to sing loudly but NOT in a forced way.

What merriman also said is right but I'll give you one last tip. If he feels any sort of strain, constriction or weird pulling of muscles it means he's doing something wrong and he should try some other way. It's NOT something that will go away over time because the vocal cords are undertrained or are getting used to it. Period. On the other hand, he shouldn't sing very lightly either cause he will always sound the way he does now. Tbh, singing lessons is all about finding the fine line between tension and relaxation.