Teaching tip of the Week – May 2, 2011
Although it is not often necessary to explain to our students in great detail the scientific function of the voice, (what matters most to the student is to get the proper feelings and to lock into them) I feel that as voice teachers it is good for us (and even essential) to correctly understand the technical mechanics of the voice.
Two weeks ago I received an email from a voice teacher saying that she was confused because a doctor (Dr. McCoy) had told her that there was no such thing as “mixing” the TA and CT muscles when singing. He said that you either sang all with TA (chest voice) or CT (head voice). She was very concerned about this. I decided that since I had access to who I consider the top two vocal scientists in the world today (Dr. Hubert Noe of Vienna, Austria and Dr. Ingo Titze of Germany) I would pose this question to them and ask for their explanation. I thought you teachers would be very interested in their responses. (We are EXTREMELY fortunate as members of IVTOM to have access to these and other brilliant doctors, scientists and professionals.)
Dean, A great question. My answer is short. We should find a time to discuss it in detail. Registers are mainly about adduction at the bottom of the vocal folds. TA contraction pushes the bottom medially. The ideal register is the mixed register, where there is a balance between TA and CT and a moderate adduction at the bottom. It is difficult to maintain the balance. Hence, exercises need to be done frequently. There are vowels that help mixed voice, and some that hinder it. So, the vocal tract plays a role. Best, Ingo
Dean, Mc Coy is not right. He tells the strict idea of Don Miller (and van den Berg and Schutte who only look at the source with respect of only 2 functions: chest and falsetto, nothing else) of the year 2000, which our friend Don has already partly left behind. This does not help for mix or middle or head ………
He forgets the influence of the vowel, the MFDR, the quality of the vocal tract, when the vocal folds are closed very fast with a long closed quotient and so on…
See this study – Hirano et al 1970: “regulation of register, pitch and intensity of voice.”
The two muscles always work together in chest and mix. The CT is the main muscle to make a tone higher by lengthening the vocal folds (comparable to a rubber band rather than to the strings of a piano) even in the lowest chest voice. But the vocal folds cannot only be stretched (by the CT) but also be stiffened (by the vocalis muscle.). This stiffening also contributes to a raising of the tone. Therefore an increase of the freqency is obtained by an activation of both muscles. The vocalis activity is also connected with the registers. When phonation frequency is raised beyond a certain point, the entire system is reset by reducing the mass in vibration very much like a gear shift in a car. This is done by stiffening of parts of the vocalis (= reduction of the mass in vibration). Then the stiffer rubber band is stretched again by the CT. The choice of the vowel helps very much to make this process easier.
Best regards, Hubert