HEY Y’ALL!!! Happy June!!
Along with lip trills and tongue trills, fricatives are very effective sound sounds to vocalize on to warm up the voice. They are all semi-occluded, meaning there are two places within the vocal tract that experience some closure- one being the vocal folds and the other being created by some combination of lips, tongue, or the roof of the mouth. There is a positive energy boost to the folds in this setup that aids in good adduction and an easy, consistent flow of air. They are also useful as cooldowns after a lot of vocal activity. Check out my video for more info and demonstrations.