How to Deal With Screechy Sopranos

1. Generally "screech" is a result of insufficient
throat space. Have them sing through the inside mouth
shape of a yawn, or the inside mouth position just
before a sneeze.
2. Encourage relaxation of the mouth and throat:
loosen and drop the jaw ("Could you put two fingers'
space between the upper and lower molars?") relax the
corners of the mouth
3. Absolve your sopranos of diction responsibilty
above E on the top of the staff.
Acoustically, the formants which define the vowels are
no longer perceptible to the ear in that pitch range,
so the trouble and tension of diction in that range
are for naught. Instead, strive for well-produced,
well-supported floaty tones, and let the rest of the
choir provide the diction.
4. NEVER allow the sopranos to sing above "forte" in
the upper register. Like the piccolo in the
orchestra, they will be heard.