While you found your answer I had $.02 to throw in. Seeing as your new to the stuff an all, and I like to throw helpful info out when I can. When your tracks are going past 0.0db you are clipping. So yeah going into the red is normally bad, I'm on PC, and have never used garage band. But, it's pretty standard for red to mean your clipping (or distorting so to speak).
You will have quite a few people tell you compression, and EQ's are what you need for just about any thing you ask. This is not always the case. While you will need them, and there is no doubt about that. Learn to get as close to the sound you want with out them first. I'm not saying to ignore them, but get a good grasp on sound before trying to sculpt it. You have to learn to draw a circle before you can make a sphere. I wish i had when I started, but alas I had no one to learn from in the beginning.
Metal... it's fun to play, and can be one hell of of a mother to record. Some times it's easy, other times your trying to fish the gold out of the garbage, and you WILL want to pull your hair out (assuming you have it). Personally for learning concepts I suggest creating retarded, crap pop-ish tracks. Metal can some times be a horrible way to learn. There tends to be so much going on it can be difficult to hone your ear, and you need to hone your ear/learn to listen. With metal every thing needs to be loud, but yet occupy its own sonic spot. It can be easy, but often is a just a pain in the rear. Save your self time 'n stress, and learn concepts (like how to properly use compression for example) by creating simple songs then go from there.
Out side of that read any bit of info you come across. No matter what genre it's geared for. Odds are you will learn a little something.
That's my story Samson, and I'm stickin to it.
