Glad to hear you liked the post, and thanks for reading! I think it depends on what you mean by “hitting” a high note. Sometimes when we try to sing a high note, we can’t hit the correct pitch at all — we either sing flat, or no sound comes out. In this case, it would be because we can’t get our vocal cords to vibrate at that high frequency.

Other times, we can hit a high note at the correct pitch, but it sounds weak or tinny. This is because the formants aren’t in the right place to give the note a boost. For example, suppose that the fundamental frequency of the note (the pitch) happens to fall between two formants, where the spectral envelope has a valley. It will be suppressed, resulting in a weak sound.

Trained singers get around this by using a technique called “formant tuning”. They change the shape of their vocal tracts depending on what pitch they are singing, to shift the formants so that one of them lines up with the fundamental frequency, giving it a boost. This is why sopranos are so difficult to understand when they’re singing in their high ranges — the formants have been shifted so drastically that all the vowels are completely distorted!

Singing technique can also make a difference to whether you can hit high pitches. There are two main ways that vocal cords can vibrate — we call them “chest voice” and “head voice”. In chest voice (which we use when talking), the vocal cords are thicker, and close completely at each vibration. In head voice, the vocal cords are more stretched so they’re thinner, and they don’t close completely when vibrating (or only very briefly). People can hit higher notes when singing in head voice than in chest voice, and they also have a purer tone.