The phrase "to control the intensity" means having the power or ability to adjust or regulate the level or strength of something, such as sound, light, or emotions. Full definition
From the box, your lighting key simply controls the intensity of a flowing effect from left to right. (invisioncommunity.co.uk)
The patients control the intensity of the stimulation, which should be felt distinctly. (sciencedaily.com)
It is tough to control her intensity so that the sheep don't just bolt in panic, and so that we get them through all the challenges on course. (carrollcountytimes.com)