Weekly Teaching Tip – Dec. 2, 2013
Question: What happens at the bridges?
Part 1: Physiology – Some Voice people say that chest is all TA and head is all CT. However, we know that this is not the case. We know that the TA and CT work together. Basically at every bridge the TA stiffens which creates a higher pitch. Between the bridges the CT stretches the vocal folds to get the exact pitches. Then at the next bridge there is another stiffening of the TA. It is much like a piano. There are about 13 different thicknesses of piano strings that cover the full range of the piano. Each thickness of string is stretched to get the exact pitches, but after a few notes you switch to a thinner string. This way you can pretty much keep a similar tension throughout the entire piano. The thinner string helps you get the general, higher pitch in the next area, then the string is stretched to get the exact pitch. If you tried to do the whole piano with the same thickness of string and get all of the pitches simply by stretching the string it wouldn’t work. The string would break. So, if someone tries to sing with all TA (pulled chest) that is like trying to string the whole piano with one thickness of string.
So, the TA generates the basic thickness (or pitch), then the CT stretches the string to get the exact pitch.
Part 2: Acoustics – Singers feel a “shift of resonance” at the bridges. Although much of what the singer feels is really “sympathetic vibrations” from different parts of the body, as they say “perception is reality” so it is something we need to be aware of and help the singer understand. Actually, all of the acoustic resonance actually happens in the vocal tract. “Chest voice” and “Head voice” don’t actually exist, but the singer feels it so to them it is reality. What the singer is actually feeling are known as formants and harmonics. This can get quite complicated, but it is helpful for teachers to understand as much about this as they can.
But as far as the singer is concerned, what is important for them to know is that they will feel a “shift of resonance” as they move through the bridge. Our brain tends not to like this so it fights it. Most singers try and stay in the “lower voice” or “let go” and suddenly jump to the “higher voice” creating a dramatic change in the vocal cord closure and resulting in either a “pull” or a “flip”. However, if the singer will expect and embrace this shift, the resonance shift they feel and the muscle balance we talked about in Part 1 will work together and there will be a smooth transition. The singer will feel these changes, but the audience will hear one, smooth, continual voice. It will sound to the audience that the singer is staying in the “same voice”, or basically sound like they are able to carry chest voice all the way up, although in reality this is not really the case.
(If you want more detailed information about this topic, my book “Teaching Good SInging” deals with this in great detail. The book contains a particularly good appendix by Dr. Hubert Noe. Also, John Henny’s “The Science of the Voice” is very good. And, Kenneth Bozeman’s book, “Practical Vocal Acoustics” is quite good.)