Imagery is usually much more effective than knowledge of anatomy when it comes to singing.
Just as when a child is learning to walk, and the only picture the child has in his or her head is arriving where Mom or Dad is crouched down, encouraging them – so the pictures in our head as we sing will guide us more effectively than constantly checking in on what every muscle, cavity and sinew is up to.
The latest effective image that I’ve discovered and tested with all my groups is the Goldfish Bowl.
Pretty simple. Hold a large, imaginary Goldfish Bowl, about the size of a volleyball, up near your face at about shoulder level – then look slightly downward and sing into it – imagining that you are filling it with sound and warm air as you sing.
Bigger, richer and much more cohesive sound from the chorus
I chose a Goldfish Bowl because it’s transparent. When you lower your hands again, it’s easier to imagine that a glass bowl is still there.
What’s going on in your mind is far more important than specific mouth shapes.
I find that if everyone is very clear about exactly what vowel the group should be thinking, then a completely relaxed, neutral mouth shape will allow the words to be crystal clear, and the sound well blended.
The synchronization will also be better because jaw hinges will not be moving different distances, and different speeds.
This technique works best when the chorus already understands the concept of target vowels, and diphthong/resolution vowels, and the importance of a relaxed tongue during the singing of the longer, initial (target) vowel.
Light = lah________eat
Day = Deh_________ee
Rose = Ro_________ooze
A high soft palate will also allow more resonance – making it unnecessary to open the mouth wide.
Eventually, when the group gets a sense of how little movement is necessary, I do allow them to open up more in the forte sections at the climax of the song.
When we train our minds to focus on the clarity of the vowel, the group’s sound is rich, resonant, blended and synchronized.