How to use the online timer
Twenty minutes is a sensible length for a practice session, because the voice tires in a way that fingers do not and pushing a tired voice is how damage happens. It is enough for a proper warm-up and one section of a song worked on carefully, which is more than most people manage in an hour of singing through things from beginning to end.
Warm up for the first five minutes without exception: gentle humming, sirens through the range, nothing loud or high straight away. Then work on one passage rather than the whole song. The count runs inside this browser tab, so leave the page open while you sing, since a closed tab ends the session's boundary without you noticing.
Stop if anything feels rough or scratchy rather than singing through it. Air conditioning is drying, and in a climate where most people spend the day in it, drinking water through the day matters more for the voice than anything done in the twenty minutes themselves. Recording a passage on a phone and listening back is uncomfortable and tells you more than another repetition.
Common questions
Why only twenty minutes?
The voice tires in a way fingers do not, and pushing a tired voice is how damage happens. Twenty minutes covers a warm-up and one section worked on properly, which is more than an hour of singing through.
What if my voice feels scratchy?
Stop rather than singing through it. Air conditioning is drying, so water through the day matters more here than anything done in the session itself. Persistent hoarseness is worth asking a doctor about.