Warming up is essential for any singer. You can be creative with warm-up exercises, but make sure that you start slow and easy and gradually become more active. Depending on the situation, warm-up exercises can be very technical and serious, or fun and playful. However, any singer’s warm-up should place the least amount of stress on the singing apparatus at first, and gradually help loosen it up. Starting with single notes, adding consonants and modulations, and then ever wider jumps is a good sequence to follow, regardless of the specific exercises you are using.
Once you’ve done some breathing exercises and loosened up your body, it is always a good idea to start singing with single notes. These should be sung in the middle register of the voice at a volume that is not too loud nor too soft, mezzo-forte preferably. A good way to start is by humming a single note and gradually modulating and spreading out into wider registers. Gradually you can start singing these single notes using the different vowel sounds and trying to make sure that they are resonating in the appropriate place for each different vowel.
When warming up a choir it is important to get the choir members to listen to one another and to start making the same sound together. Single-note warm-ups are a great way of achieving this. A good exercise is to play a note on the piano, then sing it yourself, and then have the choir sing it back. At first the sound will probably be uneven, with some people off-tune. Repeat this until you feel that the quality of the result is good. After everyone is singing the right tone, have your choir members mark time with a percussion instrument, clapping, or stomping their feet while they sing. Four beats for each note. So: play the note on the piano while the choir marks four beats, sing it yourself or with the soloists for four beats, and then have the whole choir sing it four beats. Repeat and modulate as necessary, changing the vowel you are using. You can also have your choir sing more by having it first sing it open, then humming it or singing it softly for another four beats.
You can start adding consonants to each long note once the choir is sufficiently warmed up.For younger choirs and for a warm-up that is more fun and active, there are many non-sense rhymes and tongue-twisters that use alliteration so that all the words begin with the same vowel. Try to have the warm-up session become gradually more active by increasing the speed at which you ask them to sing, or asking them to gradually do more things, like combining articulations or singing loud and soft notes alternately. You can get creative here and choose different words and activities that you know your choir will enjoy. “Bumblebee” is a fairly common word that is used by choir directors, and you can replace the first letter with other consonants, like “Tumblebee” or “Wumblebee” This is a chance to add variety to your warm-up sessions and make them more fun for everyone involved