The purpose of warm-ups is to help choir members learn certain techniques for more effective voice control such as breathing, vowel tones, and intonation. Each week, I pick a warm up exercise that addresses one of those targets. I choose my warm-up to emphasis something that will be needed in a song that will be taught that night. If the warm-ups don't have a direct connection to the music, choir members will feel it is a waste of time, and will either not fully participate or come in when they think that part of rehearsal is over. I even go back to the warm-up exercise if we hit a trouble spot in the song.
I focus a lot on diction and blend. I explain things like diphthongs and the vowel sounds that use them and why it's important to learn to sing them correctly. Example: the long "a" sound is eh ee. So for our exercise we sustain the "eh" and clip the "ee". I explain that if they pronounce in singing the way we talk often the diction is lost to the audience unless they already know the song. so we my do 13531 (nee Nehee Nahee (the long "I") No (long o) and Noo (long double o). we often start at low register (G below middle C) because in female register this is the lowest classical note for altos and the octave below is the lowest bass note, G below low C. I also tell them that we don't flinch when we are out of range; simply drop out, but when you feel you are at your peak, try one more level up, then drop out. the last section to drop out should be first sopranos and first tenors.
I seat my choirs according to 8 parts (first sop on the top tiers of the soprano section, 2nds down front, bass/baritones next to them tenors (first tenors in the top tiers, 2nds in front) altos (first altos lower tiers, 2nd altos in top tier) This helps me to identify who is being lazy during warm-ups and who is dropping out before they should based on what I know their range to be.
When we are doing a song that requires breath or dynamic control, our warm-up reflects this with hah's, consonants, and breathing exercises.
Feel free to contact me if you have any more questions.
Starkovich