From what I understand, there is a limit to the pitch you can sing strongly at before the 'head voice' kicks in. I don't know if you can increase that limit over time, but at this point, I'm struggling with just the transition. I'm practicing singing Last Goodbye by Jeff Buckley, and it involves large pitch shifts over and over in the chorus. I am finding it very difficult. My voice sometimes squeaks as it tries to shift from the chest voice (I might be using the wrong terminology here) to head voice. Can you give me advice and tips as to how I can better achieve this transition? Are there any particular exercise that might target this skill? Also, is my knowledge on the subject incorrect or incomplete? I've always wondered if you can force yourself to sing at high pitches without shifting to the head voice.