Vocal cords are a group of cartilages, musles and ligaments. Inside your larynx from front to back.In inhalation the diaphragm descendsYou need a balance amount of air, for example, in high pitch because when you send too much air to your vocal cords, their instinctively try to holding back. So, with more air you send, the tighter your vocal cords have to get to hold it back. Key Word is balanceResonance is the modify tone send from de vocal cords which travel to the spaces since the vocal cords before leaving your mouthIt is important to keep he larynx in a natural position. In doesnt matter if we need to sing a high or low pitch.Your lowest note it is the pitch you can sing without move your larynxThe first passaggio its complicated because the muscle outside the larynx try to stretch the vocal cord to get necessary tensin (tension is good to close vocal cord). The higher you sing the less air you should use. Your outer muscles will interfere in the vibration process whenever you use more air than your vocal cords and the other muscles inside your larynx are able to handle.They happen automatically when you condition your larynx not to move, by relaxing your outer muscles and by allowing your vocal cords to thin and then shorten for higher notes to insure that your outer muscles stay relaxed