If we sing the vowel ‘ee’ the way we say it in English it will always be strident.
The problem is the quiet ‘yuh’ at the back end of the way we speak the vowel. And it’s worse than that. The ever vigilant tongue, who knows about this ‘yuh’ spends most of what should be target vowel time preparing to scrunch up for it. It’s so excited about it in fact, that it will begin its scrunch up almost immediately that the ‘ee’ vowel starts.
Tongue tension produces a strident sound. Think of your best imitation of the Wicked Witch of the West. Lots of tongue and jaw tension.
If your first language is Italian, French or Spanish this tongue tension doesn’t apply to you because the ‘ee’ sound (written as ‘i’) has no resolution vowel – and your tongue knows how to relax whether you’re saying or singing it.
So what’s the solution for the rest of us?
I recommend that my singers think really stupid thoughts as they sing ‘ee’. It ends up being more of an ‘eu’ than an ‘ee’, but in the context of the word it’s unnoticeable to the listener – other than the fact that the sound is round and blended.
Also, creating lots of space between the back teeth automatically relaxes the jaw and tongue – which helps with a richer sound.
When it comes to high notes though, I ask my singers to not even pretend that they’re singing ‘ee’ and just go straight for the dumbed down ‘eu’ sound.
When singers complain that they can’t reach a particular high note that has an ‘ee’ as the target vowel, it generally means that their tongues are gradually tightening up for the ‘yuh’. And this increasing tongue tension is choking off the sound. Once they change what they’re thinking to ‘eu’, singing the high note becomes much easier.
Sopranos and Barbershop Tenors are already no stranger to slight vowel modification in the high register, but it will work for all voice parts.