Singing - Correct Posture and exhale? Why higher notes hit vibrato?

Question:

Singing - Correct Posture and exhale? Why higher notes hit vibrato?

Hi I've been learning singing on the net and taking me a while... I know its not the good way of learning but then I havent had a chance to search for a good singing teacher yet. So neways. I've tried to learn for abt a year now. I understand all the basics but putting it into practical action is different.

Just to make sure. when you have correct posture u stand straight with ur chest up right? When I do that I can feel my area below the ripcage front and back expand. When I exhale do I have to hold the air or just let it naturally contract?

The last question I have is that...I realised when I sing high notes I can sometimes hit vibrato. I'm not exactly sure if it is but I realised this and don't understand why.

Thanks in advance , please help me out!

Additional Details

5 months ago
so I contract...but do I have to make it contract slower or does it naturally happen wen u have raised chest?

Also how come wen I use my diaphragm to sing i still have tension in my throaT?

Best Answer - Chosen by Asker: 5 months ago
so I contract...but do I have to make it contract slower or does it naturally happen wen u have raised chest?

Also how come wen I use my diaphragm to sing i still have tension in my throaT?