Any vocalizes you choose should be descending from above the "gap" to keep from developing more stress than is built up in the singer already. Certainly descending. sliding hoos would be appropriate. Keep everything light over this area. But, mostly, The voice maturaation will take care of the issue IF, IF! there is no forcing.

  Since I taught in a 9-12 high school, my singers were generally 14 yr old boys which make a big difference, as you know. But here is what I discovered with the help of workshops with Dr Cooksey, often referenced on Choralnet, and Bob Zazarra from New York State.

     Whenever I auditioned a new singer I would aske him to count down from 20 during which I would find the tone on which he settled. If the singer "chanted" on G below middle C, he was an unchanged voice.

     If the tone was the E below, the voice was beginning to change--and here is where that gap appeared, invariably. There might have been high notes in the treble, no falsetto. This might last for sometime and is frustrating for all. The trick is to let the young singer know that this is predictable and that "this too will pass" and make no more about it." Sing what you have and hear what you can't."

    When the "chanting" moved even to the D below, the treble notes may disappear and the poor kid may be left wiith, perhaps, five note, bass c,d,e,f,g, and nothing above. He often will force down an octave to low bass notes and here the danger of the boy becoming stuck in the mire and much of "woofing" only these low notes. Again, keep doing descending vocalizes, melding the parts of the range.

   By the time the chanting has move to c or b, the gap may well be filling in. Young tenors may stay here for a while but all men will probably be chanting at low g where the voice will be intact enough for real singing to develop. If I could keep the guy singing and knowing the process, I had a lifelong singer. Sometimes, however, the guys did not settle until grade 11. But when this happened did I have a singer!

 

Simon,

 

This is an extremely common phenomena in boys' changing voices. I've taught middle school boys for 20 years and I almost always have at least one with this hole int heir voice very year.  The area you spoke of is the most common place to find the "gap" or hole. Cooksey's research on boys' voices talks about this extensively. In Cooksey's terminology, he is a Mid Voice II and I've found it very common in both Mid Voice II and Mid Voice II-A voices. Spend a lot of time working on falsetto and stengthening the pitches he can sing. Learning good technique will strengthen all the muscles of the vocal mechanism and help him through this process. Eventually, the gap gets smaller and then disappears - his vocal folds are just not vibrating together cleanly as they grow. It's a frustrating, but common problem with boys at this stage of change. 

 

Mary Jane Phillips