hmms.. from what i know the best singers have an octave range of hardly more than 3.5 and thats ALOT! i find it hard to believe that someone has a full 5 octave range with every note to be sung clearly and precisely, let alone a 7 octave range.

The process of learning to sing is best done with either a good instructional book or a good teacher who´s into rock. you can do ALOT of harm to your voice when learning it yourself without having a good plan how to build it up. Be carefull when choosing a teacher - some do have a pretty strange view of things and that can also be very dangerous for your voice. What you need to learn before starting to sing is a propper breathing technique - thats the very basic of singing. The basics of rock and classical singing are the same to a certain point - but if you want to learn to sing metal or rock, you should definitely not get too much into classical-voice training.